Does masturbation affect IQ?

Intellectual disability and guilty capacity


Anyone who looks up the question of the assessment of culpability in the case of intellectual disability in forensic-psychiatric textbooks will often and in some cases be very clear in a schematic presentation of an assessment criterion that severe and severe intellectual disability abolished the ability to discern, at Moderate intellectual disability partly revokes the ability to see and partly to control and at Slightly reduced intelligence either the ability to understand or the ability to control either reduced or canceled be. However, as a rule, a psychopathological foundation of these principles or an explanation of possible justifications for impaired ability in accordance with §§ 20, 21 StGB is not required. In the following, an attempt will be made to provide further orientation in the assessment of the culpability of offenders with intellectual disabilities with reference to current diagnostic criteria and concepts of intellectual disability, which go beyond the isolated determination of an IQ value.


Whoever looks up the question of criminal responsibility with intellectual disability in forensic psychiatric textbooks, can often find and sometimes very descriptive, an assessment measure in schematic form. These states that in severest and severe intellectual disability the ability to reason is nullified, in moderate intellectual disability partly the ability to reason and partly the accountability is nullified and in slight intellectual disability either the ability to reason or the accountability is either diminished or nullified. A psychopathological foundation of these principles or a presentation of possible reasoning pathways for impairments of abilities according to §§20, 21 German Penal Code (StGB) is, however, as a rule not provided. In the following, an attempt is made to provide further orientation for the assessment of the criminal responsibility of offenders with intellectual disability, with reference to the current diagnostic criteria and conceptions of intellectual disability that go beyond the isolated determination of an IQ value.

Definition and diagnosis of intellectual disability

The positive definition of the term intelligence is the subject of discussion and ongoing differentiated concept formation (for an overview: Deary 2012). The forensic-psychiatric perspective is interested in the identification and communication of ability limits and disorder-related deficits, especially when it comes to assessments on the question of culpability in criminal proceedings. This enables a more pragmatic (and in foro easier to communicate) approach than the positive definition of the concept of intelligence. But intelligence levels that are below average for diagnosis are also conceptually and conceptually inconsistently defined.

The ICD-10 marked with Mental retardation (a term preferred in this work) a manifestation of the development, halted or incomplete development of mental abilities. Skills that contribute to the level of intelligence, such as cognition, language, motor and social skills (ICD-10: F7), are particularly impaired. A classification according to ICD-10 into 4 degrees of severity of intellectual disability (mild, moderate, severe, severe) is based on test psychologically determined intelligence quotient (IQ) values, which are intended as guidelines and whose rigidly borderline application is not recommended.

Results of test psychological intelligence diagnostics have been used for diagnostic categorization since the 1960s, which enabled a conceptual replacement of previous, also pejorative diagnostic terms without giving up an internal differentiation of the spectrum of intellectual impairments. The differentiation between debility, imbecility and idiocy established since Kraepelin - all outdated and also in foro avoidable terms; for a brief history of terms: Häßler (2005) and, in addition, Schalock (2007) - gave way to the distinction between mild (total IQ 50–69), moderate (total IQ 35–49), severe (total IQ 20–34) and most severe intellectual disability (total IQ below 20). These 4 categories form the subdivision of a continuum, the boundaries of which can only be determined pseudo-precisely in individual cases, as well as the demarcation to the learning disability that is less severe and not to be added to the diagnosable intellectual disabilities (total IQ 70–84).

With established test procedures, the classification of the individual total IQ in a Gaussian normal distribution curve, the peak of which, according to the convention, is an IQ value of 100, is valid and reliable. Here, causes for incorrect, v. a. False-low test results are taken into account and, if necessary, also discussed in an expert manner (for example, motivational aspects, sedating medication, comorbid disorders or situational influencing factors before or during the test). Differentiating examinations also enable the assessment of the structure of individual intelligence including talent strengths and weaknesses. This illustrates that numerically comparable total IQ values ​​can result from very different cognitive profiles, which makes the isolated consideration of an IQ value for the assessment of ability in accordance with §§ 20, 21 StGB inadequate. In particular, an argument based solely on time-saving screening examinations is not advisable. This is all the more true if, on this basis, a position is also taken on measures for improvement and security (Leygraf 1988, p. 53: in more than one in four of the patients admitted to psychiatric measures as oligophrenic [MRV] this clinical diagnosis was a test psychological one Check in the course of the placement did not stand).

Knowing the degree of severity of intellectual disabilities, it is important to point out clearly, especially in psychiatric-legal exchanges, that a easy Intellectual disability already one heavy and represents complex impairment. This can be shown by specifying the prevalence of the (sum of all degrees of severity of the) intellectual disabilities, which is approx. 1–3%, from which it follows that approx. 97–99% of the population have a higher IQ than the total number of those that meet the diagnostic criteria of intellectual disability.

In addition to the definition of the ICD-10 cited in the introduction, they can be used for forensic and psychiatric purposes further definitions of intellectual disability at. The most differentiated formulation in a forensic-psychiatric textbook - with conceptual proximity to the ICD-10 - emphasizes developmental aspects in addition to the lack of aetiological specificity and emphasizes disorder-immanent adaptation and coping difficulties with the inability to only compensate for deficits independently: shows itself in childhood as a mental developmental disorder and then in school age as a learning disability, but is also determined in adulthood by the fact that the mental maturation required for an independent life remains incomplete in the long term and the deficits in the course of development are insufficient despite care and support can be compensated ”(Lammel 2010, p. 377).

The domains suggested by Lammel (2010) as meaningful forensic-psychiatric assessment correspond to the recommendations of the American Association on Intellectual and Developmental Disabilities (AAIDD; Luckasson et al. 2002; updated: Schalock et al. 2010): For the clinical assessment of the intelligence level is integrative assessment of skills and abilities in the domains of language, reading / writing / arithmetic, self-determination, activities in daily life, professional skills and interpersonal relationships are recommended. In addition to the cross-sectional investigation, personal and third-party anamnestic information on biography, development, successful or failed schooling as well as the extent of independence and help are essential, which relativizes the isolated consideration of IQ values.

in the DSM-5 is now from a intellectual impairment spoken at an early stage of development, which includes intellectual as well as adaptive functional deficits with impairments in conceptual, social and everyday practical areas. In contrast to ICD-10 and DSM-IV, degrees of severity are differentiated according to DSM-5 according to the individual adjustment performance and no longer on the basis of determined IQ value limits.

For the ICD-11 becomes the wording Intellectual development disorders expected. In addition to a below-average level of intellectual functioning, deficits in cognitive domains and behavioral variables are described, which can be mapped with neuropsychological diagnostics and recording adjustment and behavioral disorders.

The developments of diagnostic criteria and conceptualizations outlined above illustrate that they are moving away from an isolated consideration of IQ values ​​(and also from the concept of intellectual disability). This does justice to the fact that intellectual disabilities are complex and heterogeneous syndromes. In particular, the greater consideration of social adjustment and emotional development deficits brings the general psychiatric-clinical diagnostic criteria back in line with the psychopathologically founded ability assessment in forensic-psychiatric contexts, which is currently not found for any other disorder group.

At the same time, a group subdivision of the intellectual disabilities from an etiological, clinical and expert point of view continues to make sense. One becomes pragmatic for all three claims with the Two-group hypothesis just (Burack 1990), who differentiates between mild and severe intellectual disabilities:

  • Moderate, severe and very severe intellectual disabilities (IQ values ​​below 50) form as severe intellectual disabilities a distinct group. Their share in the totality of intellectual disabilities is approx. 20%. To the left of the normal IQ distribution, they form their own frequency curve, overlapping with the normal distribution curve, with a peak around the IQ value 30. They are much more common than slight reductions in intelligence due to identifiable organic causes, and often show signs of dysmorphism and organic findings. Those affected suffer from a high rate of somatic and psychiatric comorbidities; they are severely restricted in their social and everyday functional level and are therefore often looked after in institutions. This, or the care in their families, in which parents and siblings are mostly of average intelligence, makes neglect and misrepresentation unlikely and has a crime prevention effect (for a historical representation of the care of the mentally handicapped in a rural environment: Moser 1971). The proportion of people with severe intellectual disabilities in forensic-psychiatric assessment collectives is therefore low, so that experts who work exclusively in criminal law sometimes have an incomplete picture of the spectrum of intellectual disabilities, which is detrimental to both the clinical severity assessment and the development of a psychopathological reference system.

    At severe and severe intellectual disabilities Expertise questions from care law dominate (prerequisite for care, need for placement or a custodial measure, sterilization, etc.). In most cases of an appraisal on the question of culpability, corresponding expert reports under care law or curative educational development plans etc. are already available. Sometimes with reference to this, if the outcome is expected, an assessment and criminal proceedings can be dispensed with and instead responded with an adjustment in care and treatment (e.g. admission to a psychiatric clinic with a specialty ward for the treatment of people with intellectual disabilities and behavioral disorders or comorbid mental disorders).

    The moderate intellectual disability is a heterogeneous disorder group and area of ​​overlap of two (clinically and etiologically clearly distinct) entities: it forms the extension of the left leg of the normal distribution curve of intelligence due to the slight reduction in intelligence; in this respect she has a syndromic tendency to be mildly mentally retarded. However, it also forms the right leg of the distribution curve for severe intellectual disabilities with an apex of this curve around an IQ value of 30; In this form, the moderate intellectual disability syndromally approximates the severe and most severe intellectual disabilities. The assessment of criminal liability can therefore - depending on the side of the specific syndrome of moderate intellectual disability - be oriented more towards the mild or the severe and most severe intellectual disabilities.

  • Slight intellectual disabilities (IQ scores 50–69) form as slight intellectual disability the left end of the Gaussian normal distribution curve of the IQ values. They make up about 80% of all intellectual disabilities and their set of conditions is strongly influenced by (family, social, cultural) environmental factors, organic findings and signs of dysmorphism are rare, life expectancy and fertility are usually not impaired. They occur in families and are overrepresented in lower social classes, so that investment and milieu factors overlap. Only a minority of those affected are cared for in institutions. Emotional and social-interactional aspects of people with slight intellectual disabilities cannot be clearly delineated from the population average. This implies that a low level of intelligence, possibly also a low level of intelligence that is worth diagnosing, is only one factor in the set of conditions for delinquent developments, so that for IQ values ​​of 70 ± 15 no different assessment criteria need to be justified.

Reduced intelligence and input characteristics of § 20 StGB

For the assignment to an input characteristic of § 20 StGB, it is not the syndrome of intellectual disability and also not a numerically determined IQ value that is decisive, but knowledge of the etiology of the intellectual disability. Clinically and psychopathologically, this subdivision is artificial, but in accordance with the initial features of Section 20 of the Criminal Code, it is necessary at the first stage of the assessment of culpability. However, this differentiation is irrelevant for the discussion of insight and control that follows on the second level. An inborn intellectual disability without a specific organic causation to be named becomes the initial characteristic Bullshit assigned. Intelligence impairments as a result of a biological-causal disorder to be named, however, are included under the input characteristic pathological mental disorder collected.

Known causes of intellectual disabilities can be divided into:

  • prenatal (genetic syndromes or chromosomal disorders, malformations, metabolic disorders, exogenous-toxic influences from alcohol [fetal alcohol syndrome, FAS], narcotics or medication as well as diseases of the mother),

  • perinatal (various labor and delivery complications) and

  • postnatal (Infections, trauma, seizure disorders, often resulting in hypoxic-ischemic brain damage).

The knowledge of organic and v. a. genetic causes of intellectual disabilities have increased rapidly over the past few decades; further developments are to be expected. For a description of relevant syndromes, the book chapter by Neuhäuser (2013) is recommended.

The proportion of tangible biological factors is greater, the more severely the intellectual disabilities are pronounced, which is why the majority of severe intellectual disabilities (in accordance with the two-group hypothesis) are to be assigned to the first entry criterion of Section 20 of the Criminal Code, but only a minority of the slight intellectual disabilities.

Behavioral disorders and comorbidity

The ICD-10 enables (still and regardless of the severity of the intellectual disability) the specification of the presence of Behavioral disorders with intellectual disabilities. Less severe manifestations (ICD-10: F7x.0) are distinguished from intellectual disabilities with “clear behavioral disorders that require observation or treatment” (ICD-10: F7x.1).

Due to a lack of concrete and operationalization of any behavioral disorders, their clinical (Allen 2008) but also expert assessment is extremely heterogeneous. Behavioral disorders are mostly understood as culturally inappropriate behavior in the context of intellectual disabilities and clearly differentiated from comorbid psychological disorders. In the currently being revised Practical guidelines for intellectual disability (Häßler et al.2014) inwardly pointing, internalizing behavior problems (fearful, retreating, avoidant behaviors, which are mostly without direct forensic relevance) are distinguished from outwardly directed, externalizing behavioral problems (which can potentially become forensically relevant): hitting, kicking, scratching, biting, Screaming, pulling your hair, throwing objects, spitting, acts of destruction, self-harm. Challenging behavior is mostly an expression of interaction and relationship disorders, experienced (physical, social) impairments or unsatisfied needs that cannot be communicated otherwise or whose frustration is responded to in a dysfunctional manner. From a forensic-psychiatric perspective, disorders of drive behavior, impulsiveness, emotional instability, disorders of the ability to bond and relate, deficits in empathy and a tendency to consume addictive substances were counted as behavioral problems (Lammel 2010, p. 395).

The severity and occurrence of these phenomena vary significantly depending on the degree of intellectual disability, the type and intensity of care, the comorbidity, the age as well as situational and environmental factors. Cooper et al. (2007) found a point prevalence of behavioral disorders of approx. 18–22%, Schützwohl et al. (2016) recently in a German cohort over 45%. The severity of the behavioral abnormalities was determined to be inversely proportional to the emotional level of development (Sappok et al. 2014), which again underlines - in addition to the low level of intelligence - also emotional and socio-interactional deficits of the syndrome of intellectual disability in their importance for phenomena to be assessed forensically and psychiatrically .

In addition, people with intellectual disabilities can participate comorbid mental disorders suffer (see Schützwohl and Sappok 2020). The information on their frequency relative to the population average differs greatly (cf. Kerker et al., 2004): Schützwohl et al. (2016) found a lower point prevalence of approx. 11%, probably also because they strictly assigned other symptoms with a disorder value to the area of ​​behavioral disorders (see above, approx. 45%). Cooper et al. (2007) found a significantly higher point prevalence of mental disorders (approx. 15–28%; with a lower rate of behavioral disorders: approx. 18–22%, see above), especially when a clinical diagnosis was made beyond the diagnostic criteria of ICD and DSM. These different diagnostic habits are sometimes the reason for differences between experts or experts and practitioners (for example in MRV clinics). These seem to be differences in the designation, but not in the designation, which underlines the value of exact descriptions of the syndrome, also with a view to changed diagnostic criteria in anticipation of the introduction of the ICD-11. The two studies cited as examples, together with meta-analytical studies (Einfeld et al. 2011), support the finding that around every second person with intellectual disabilities has behavioral disorders and / or comorbid psychological disorders, which in each case provides grounds for diagnosis, treatment and sometimes assessment.

In principle, all other diagnoses in the psychiatric field can appear as comorbidities. People with slight intellectual disabilities are more likely to have comorbid mental disorders in the type and severity of people without intellectual disabilities. Cooper et al. (2007) found affective disorders (6.5%), anxiety disorders (6.0%) and addiction disorders (1.8%) as frequent secondary diagnoses in this cohort. With the high rates of comorbid schizophrenia diagnoses (5.8%), there is a risk of confusion with schizophrenic residual and negative symptoms. In severe intellectual disabilities, autism spectrum disorders were described as comorbid (10.1%), followed by mood disorders (6.7%) and schizophrenia (3.5%); Dependency disorders are less common (0.5%). In a review of the literature, comorbid mental disorders were reported in 31–75% of the cases of offenders with all degrees of intellectual disability, with a clear predominance of schizophrenia and schizophreniform disorders (Hobson and Rose 2008). This finding corresponds to earlier studies on German MRV inmates (Leygraf 1988).

The psychopathological assessment can be significantly more difficult in the case of intellectual disabilities. Those affected can sometimes report impairments and symptoms that they have not experienced, which is referred to as "underreporting". The diagnostic criteria of mental disorders according to the ICD and DSM can often no longer be assessed with the necessary certainty in the case of more than slight intellectual disabilities. In the case of severe and severe intellectual disabilities, the use of diagnostic criteria that are adapted to the specifics and psychopathology of people with intellectual disabilities is therefore recommended (Diagnostic criteria for psychiatric disorders for use with adults with learning disabilities / mental retardation, Dc-lD; 2001). However, these are not available in German translation. If symptoms of a comorbid mental disorder are incorrectly assigned to the syndrome of intellectual disability, one speaks of “diagnostic overshadowing” (Reiss et al. 1982). On the other hand, it should be avoided to assign secondary diagnoses that are actually justified by symptoms of intellectual disability or associated behavioral disorders.

Insight and control ability

With Insight In the sense of §§ 20, 21 StGB, the core is the knowledge or the accessibility of knowledge that a specific action is prohibited. Insight into criminally relevant prohibitions is trained in the application of development progress in socio-moral development and intelligence in social interaction. Regardless of the specifics of developmental, differential or social psychological theories, it is already so well developed in childhood and long before reaching criminal responsibility that it is assumed to be given from the age of 14 onwards. In this context, insight within the meaning of Section 20 of the Criminal Code does not mean a primarily psychological construct, but an individual ability related to the specific allegation of the crime to “see the injustice of the crime”. The specific requirements for insight are therefore also dependent on the complexity and character of the act. Insight can either be present in relation to the act or not. If it is judged by an expert that there is a possibly significant reduction in the ability to understand, the court is obliged to examine whether, in relation to the act and the time of the act, the unlawful insight was actually given or to be denied in the event of a reduced ability to see. The non-reproachable lack of insight into injustice with significantly reduced ability to understand falls under the condition of § 20 StGB. The reproachable lack of insight into injustice with significantly reduced ability to understand qualifies for the application of § 21 StGB and, like the first-mentioned constellation, does not conflict with an order of § 63 StGB. Accusable lack of insight with insignificantly reduced ability to see and action-related existing insight despite possibly significantly reduced ability to see are not prerequisites of § 21 StGB and cannot justify an order of § 63 (Lammel 2010).

With Controllability In terms of §§ 20, 21 StGB, the ability to act in accordance with judgment is described. It is to be assessed on an act-related basis if the ability to see things is affirmed ("if the act is committed ... to act according to this insight"). The practical procedure for the expert assessment of the ability to steer does not differ from the procedure for other disorders in the case of intellectual impairment. Reference is made to conceptual considerations of Janzarik's action control and management in this volume, as well as to more comprehensive earlier presentations (Janzarik 1995). Reconstruction of the psychopathological syndrome, in particular of abilities and ability limits related to the crime, forms the basis for the assessment of criminal offenses by persons with reduced intelligence As with other impairment patterns, the relevance of further factors must also be checked for diagnostic-worthy intellectual impairment in addition to their importance in the conditional structure of the crime: These are primarily growth and socialization conditions, learning and shaping effects, the influence of addictive substances in longitudinal and cross-section, In addition, interactional and situational influencing factors as well as comorbid mental disorders and their weighted differentiation from one another.

Symptoms of significance for the assessment and specific constellations of the assessment of the culpability in the case of intellectual disability

In the first part of this thesis, reference was made to DSM-5 and ICD-11, in addition to that in the narrower sense intellectual-cognitive deficits the impaired adaptive performance velvet conceptual, social and everyday practical ability restrictions constitutes the syndrome of intellectual disability. Besides that, you can Behavior disorders Be part of the syndrome of intellectual disorder, which is additionally caused by comorbid mental disorders (especially due to schizophrenia, paraphilias, personality disorders), acute or chronic consumption of Addictive substances and social factors or misleading learning experiences forensic relevance.

The above-mentioned aspects can, individually and in combination, cause impairment of ability in accordance with §§ 20, 21 StGB. In the following, they are to be discussed with regard to possible effects on the criminal responsibility related to the offense and supplemented by some specific constellations. It should not be about the presentation of psychological theories on intellectual disability (introductory: Sarimski 2013) or on moral development (in the tradition of Kohlberg, for this: Knapheide 2013), but about psychopathological symptoms and syndromes that contribute to the argumentation in the assessment of guilt Determine intellectual disability.

It will not be possible to derive legal consequences for the application of Sections 20, 21 of the Criminal Code, as it were, from individual symptoms and without reference to the crime. The reason and the leitmotif of this article is that instead of apodictic principles, an individual psychopathological foundation is required. However, specific symptoms and relevant disruption constellations should be presented, which can be checked for their relevance in individual expert reports. Ultimately, the ability assessment will focus on psychopathological reference system (Saß 1991, with further references) orientate. Saß (1991, p. 274) formulated that by examining the drive and affect events, the emotional differentiation, the ability to orientate themselves to values ​​as well as the ability to judge and criticize in a comprehensive analysis of the entire life circumstances, the professional performance and the contact area, the judgment of guilty responsibility contributes Reduced intelligence (compared to other input characteristics) is relatively unproblematic. With reference to current classification systems, the following symptoms and domains can be of particular importance in the assessment of ability in accordance with Sections 20, 21 of the Criminal Code:

  • Intellectual-cognitive deficits: Here, cognitive functions denote the totality of the processes with which knowledge about the environment is acquired. Severe cognitive deficits (especially in the domains of perception, directing and dividing attention, mnestic functions, reasoning, processing speed; Bertelli et al. 2014) can prevent the formation of insight: In the case of "failure of intellectual mapping" (Janzarik 1991 and in this issue) Insight training is not possible, nor is it possible in the case of severe deficits in active and passive language skills that make communication impossible.

    Executive deficits in action planning and control, including the evaluation of action alternatives and consequences as well as the inhibition of irrelevant or dysfunctional readiness to react, can affect the control ability within the meaning of §§ 20, 21 StGB.

  • Disturbed adaptive performance: Disorders of the adaptive functional level in the case of intellectual disabilities are of particular forensic relevance. This means disturbances of the appropriate and social expectations corresponding situational behavior in the whole reality of life. Therefore, the family of origin, social environment, including the important aspects of partnership and sexuality, school environment, use of local public transport, workshop work and employment, i.e. the degree of self-determination achieved and the degree of relationship ability or the severity of social interactional conflict.

    People with intellectual disabilities have overwhelming and frustrating relationship experiences that are consequently negative and ultimately less supportive as a result of rejection or avoidance. Skill deficits and a lack of social learning together give rise to deficient adaptation strategies. In addition to withdrawal and avoidance, social misjudgments, disruptive actionism and border violations can result. Strategies for action are not very differentiated and, insufficiently adapted, are applied to changed environmental conditions. The spectrum of interests can be reduced; Sometimes an inflexible orientation towards individual interests or idealized or unattainable goals becomes forensically relevant, v. a. if this is paired with strategy deficits (in the areas of partnership, sexuality, job or driving license). In social situations, a high tension of needs with previous need frustration can intensify an existing weakness in defending needs. Often there are limited opportunities to communicate and satisfy needs in a socially acceptable way. Sthenic affects (anger, anger, etc.) can arise from lack of understanding, failures or insults. Verbal strategies are limited, which increases the likelihood of dysfunctional actions. These can be manifold, including withdrawal, alcohol consumption, use of force, acts of destruction and arson. At the level of §§ 20, 21 StGB, these factors can plausibly cause impairments up to the abolition of the ability to control.

  • Behavior disorders: Acted behavior disorders in the context of the syndrome of intellectual disability must be distinguished from misconduct in social situations due to deficit-inflexible action strategies. These destructive-dysfunctional acts are often primarily self-harming or self-damaging. Externalizing misconduct can, however, also become relevant under criminal law (hitting, kicking, scratching, biting, yelling, pulling your hair, throwing objects, spitting, acts of destruction, etc.). These actions, as well as disturbances in drive and impulse control as well as the consequences of emotional immaturity and instability can be impulses that urge you to act and have a negative or negative effect on the ability to inhibit within the meaning of §§ 20, 21 StGB.

  • Comorbid mental disorders: People with intellectual disabilities can in principle suffer from all other mental disorders. Comorbidities must be assigned to the corresponding input characteristics of Section 20 of the Criminal Code. Comorbidities associated with criminal acts are schizophrenia, but also (above all antisocial) personality disorders, paraphilias and dependency disorders, i.e. those that are risk factors even in an average intelligent group of offenders. Some of the possible comorbid disorders are the subject of articles in this issue. Partial causes in the conditional structure of criminal actions must be psychopathologically founded as such and their ability effects must be assessed integratively in accordance with §§ 20, 21 StGB. It is not about the mere summation of diagnoses or input characteristics, but about the resulting impairment of ability, what that is for psychopathological reference system (Saß 1991) offers.

  • Addictive substances: Information on the point prevalence of substance abuse and addiction disorders as comorbidities with intellectual disability diverge. Cooper et al. (2007) determined about 1% of all degrees of intellectual disability. The addictive substance alcohol is by far the number one. For people with intellectual disabilities in residential facilities and inpatients with intellectual disabilities, higher prevalences were reported (approx. 4% alcohol-dependent, approx. 7% risky or harmful use; Schubert and Theunissen 2004). These figures fit dimensionally with earlier studies of persons placed in the MRV with intellectual disabilities (2.5% alcohol dependence and 11.5% alcohol abuse; Leygraf 1988). If young people with learning disabilities are also included in the studies, the proportion of those affected with alcohol and narcotics (BtM) experience increases significantly and, in terms of conditions and substances consumed, then resembles the age cohort without intellectual disabilities (Didden et al.2009; for Germany: Sarrazin and Fengels 2009). Alcohol and BtM consumption is a criminologically significant factor among others, especially for people with a slight intellectual disability. In the case of the offense-related interaction of ongoing and / or acute addictive substance influence and a reduced intelligence, just like with comorbid mental disorders, the reconstruction of the psychopathologically justified deficit syndrome including the resulting effects on the offense-related insight and control ability is important. For acute impairments, beyond drinking quantities and toxicological-numerical reference points (breath [AAK], blood alcohol concentration [BAK]), deficit reconstruction is carried out with the help of Axial Syndromal Assessment (Kröber 1996) advised. In the case of intellectual disability, possibly underlying organic brain impairment, somatic comorbidities and psychotropic medication, lower amounts of alcohol can be sufficient to increase existing skill deficits quantitatively (§ 21 StGB) or qualitatively (§ 20 StGB). On the other hand, it is important to prevent the privilege of getting used to alcohol by considering the AAK / BAK alone.

  • Social factors and malforming learning experiences: In particular, slight reductions in intelligence are largely determined by the educational and milieu conditions in terms of the structure of conditions, course and behavioral phenotype. Growing up under socially marginalized, dissocial conditions, in addition to insufficient schooling, can shape the emotional and social development deficit far more than a low level of intelligence per se. The overrepresentation of slight intellectual disabilities in lower social classes is an acceptable expression of depression. Lammel summarized that "the forensic relevance of nonsense increases with the impoverishment of the mentally handicapped and decreases with the structuring of their everyday and living environment" (Lammel 2010, p. 435). All risk factors for crime that are also known in (low) normal-intelligent people and for the development of a crime-related constellation (Göppinger 1985) can contribute. These include a lack of performance orientation with neglect of the work and performance area, a relationship to money characterized by high expectations and overestimation of oneself, unstructured leisure behavior with peers who are just as distant from the norm, the lack of perspective-based life planning and an affinity for addictive substances. These aspects can be an indirect expression of an intellectual disability, but as criminogenic risk factors, the less severe the intellectual disorder is, the more important they are. Already Böker and Häfner (1973, p. 267) described that a reduction in intelligence in the conditional structure of (violent) delinquency "is more of a complication factor that becomes effective through reduced self-control or increased sensitivity to stimuli or instincts than a specific causal factor. More specificity for the increase in risk is presumably a dissocial personality disorder that is predisposed to openly aggressive behavior, which is mostly attributable to feeble-minded perpetrators [n = 68] was detectable. "

    In the combination slight mental retardation plus Non-normative dissocial undesirable development it will practically never be possible to reconstruct a disturbed insight into injustice. Usually, behavior control in the dissocial “ingroup” also illustrates a repertoire of adaptation services that can be called up as required. When examining the cumulative effect of intellectual disability and antisocial behavioral styles on the act-related control ability, it comes - as is the case with antisocial personality disorder; Habermeyer's contribution in this issue is to differentiate the ability to control action, which is impaired as a result of a disorder with a psychopathological quality, from the competent but norm-deviating use of antisocial behavioral styles.

Criminological aspects and specific questions

People with intellectual disabilities have an increased risk of becoming victims of crime, but are also overrepresented among perpetrators: In Scandinavian registry studies, an increased rate of criminal offenses and convictions was found for them (Hodgins et al. 1992 and 1996). There are no comparable studies for Germany; smaller studies point to similar relationships here. As offenses committed by persons with a mental disability placed in the psychiatric MRV (n = 121), sexual offenses (50%), property offenses (18.2%), arson (13.2%), homicides (12.4%) and bodily harm (5%) have been reported since Leygraf (1988, p. 226). This list does not do justice to everyday life at German district courts, where property offenses, stealth stealth, threats and insults are negotiated for people with (especially mild) intellectual disabilities, but this does not provide any reason to discuss the introduction to the MRV. As serious offenses of lawbreakers with intellectual disabilities are nevertheless often Offenses against sexual self-determination, arson and Violent crimes listed, which should therefore be discussed separately below.

Sexual issues are often described for people with intellectual disabilities, some of which are Offenses against sexual self-determination favor, including (according to Häßler 2015, p. 344) the lack of empathy and sustainability in the formation of relationships; Directness of sexual activity without regard to others (e.g. masturbation in public); Danger of genital (self-) injury; Object orientation during sexual activity; often bisexual or autoerotic activity; Tabooing of sexual behavior and sexual needs; Lack of adequate education and thus little knowledge of sex; frequently victims of sexual abuse by other people with impaired intelligence or those who are not (Zemp 2002). Sexually deviant behavior can also be caused by a discrepancy between the degree of physical maturity and psychosexual development - with particular forensic relevance in boys and young men with mildly intellectual disabilities.

In addition to these specific sexual factors, cognitive, affective and socio-interactional deficits in the intellectual disability can be significant, v. a. a disturbed ability to postpone needs when there is a high tension of needs as well as insufficient ability to anticipate and plan. A reduced intelligence can result in different degrees of both communication and competition disabilities; Pedosexual acts can also be the result of turning to children if contact with potential adult sexual partners is fearfully avoided or unsuccessful and frustrating. As an alternative, increased rates of “hands-off” offenses are also reported.

In addition, comparable situational factors act in the framework of sexual delinquency in people with and without intellectual disabilities. Even in the case of determining a low, possibly low IQ value for diagnosis, neither a sexual history nor the reconstruction of the impairment picture and the discussion of other factors relevant to the assessment are unnecessary (article by Briken in this issue). Sex offenses are a frequent issue in review collectives. The reason for this could also be the reporting behavior in supervising institutions, as well as the question of continuing danger (Lammel 2010, p. 433), which ultimately also contributes to the high proportion of intellectually impaired sex offenders in the MRV (Leygraf 1988).

The working group around Häßler examined young people Arsonist and found people with reduced intelligence to be clearly overrepresented (Buchmann et al. 2000; Häßler 2015). A retrospective study by the Heidelberg expert opinion archive also identified “overstrained debiles” and (serial) incendiaries with impaired intelligence with a fire-specific learning history as distinct groups of perpetrators (Barnett 2005 and 2008). The diagnosis of pyromania should or may not (at least according to DSM-5: F63.1) be given in people with intellectual disabilities (and is anyway more of a psychiatric-historical relic than forensic-psychiatric use). In the case of arsonists with intellectual disabilities, a fire-specific learning history and / or a situational background can usually be derived, so that the arson is carried out accordingly Instrumentality and delictant decedent emotion can be categorized (Barnett 2005 and 2008). Accident-like acts, arson as helplessly overwhelmed behavioral disorders and motivationally incorrectly shaped (for example sexually connotated) acts are often suitable in the context of intellectual disability to abolish or at least considerably limit the ability to control the act.

Some of the characteristics of the syndrome of intellectual disorder discussed in this post can be linked to Violent crimes be associated. A low level of verbal competence suggests that non-violent conflict resolution strategies will be used up earlier. Affected people have exclusive, frustrating relationship experiences. The ability to express and regulate emerging (sthenic) affects are limited. Irritability, excitability and emotional lability can lead to aggressive behavior disorders. Personal experience of violence, socialization in a milieu affinity for antisocial violence as well as situational excessive demands or intoxication can all contribute to the use of violence. This, as well as an expression of adjustment and behavioral disorders, can result in the cancellation or possibly significant impairment of the crime-related control ability. Böker and Häfner (1973) limited the risk of violent crimes to a subgroup of intellectually impaired perpetrators who are “basically not average or uncomplicated mentally handicapped people”, “but demoralized demons”. In line with later research, they found the following factors associated with violent crimes among mentally impaired perpetrators: “Broken parent family, exposure to crime and alcoholism; dissocial personality disorder, tendency to openly aggressive behavior, inadequate occupational, social and family adaptation; Physical injuries with sexual offenses in the past; chronic alcoholism, alcohol consumption before the act ”(Böker and Häfner 1973, p. 268). In this constellation, delinquent people with a (low) normal level of intelligence do not differ from offenders with a slight intellectual disability.


With reference to the two-group hypothesis, it was stated that the differentiation into severe (IQ value <50) and mild intellectual disabilities (IQ> 50) makes sense from an etiological, clinical and expert point of view. The dichotomy is also justified from a forensic and psychiatric point of view, despite the syndromic heterogeneity of that “extremely variegated group of forms of disease” (Kraepelin 1903). For most severe, severe and also for a large number of moderate intellectual disabilities The prerequisites of Section 20 of the Criminal Code can generally be justified with reference to the symptoms and deficit constellations compiled in this work. However, this cannot usually be determined on a psychopathologically sound basis for the slight intellectual disability. In the event of mild mental retardation In spite of intellectual and cognitive deficits, it will generally not be possible to reconstruct a lack of insight into wrongdoing. A Impairment or cancellation of the crime-related control ability is to be discussed in the case of slight intellectual disabilities, primarily due to a deficit in adapting, accompanying behavioral disorders, comorbid psychological disorders including addictive substance impairments and as a result of (above all antisocial) shaping effects. Therefore, the (diagnosis-worthy) slight intelligence impairment, similar to the (not diagnosis-worthy) below-average intelligence, is often a factor in the conditional structure of criminal offenses among others, the offense-related impairment of ability of which can be discussed with the help of the psychopathological reference system.


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