Patterns of risk-Using machine learning and structural neuroimaging to identify pedophilic offenders.

Background: Child sexual abuse (CSA) has become a focal point for lawmakers, law enforcement, and mental health professionals. With high prevalence rates around the world and far-reaching, often chronic, individual, and societal implications, CSA and its leading risk factor, pedophilia, have been well investigated. This has led to a wide range of clinical tools and actuarial instruments for diagnosis and risk assessment regarding CSA. However, the neurobiological underpinnings of pedosexual behavior, specifically regarding hands-on pedophilic offenders (PO), remain elusive. Such biomarkers for PO individuals could potentially improve the early detection of high-risk PO individuals and enhance efforts to prevent future CSA. Aim: To use machine learning and MRI data to identify PO individuals. Methods: From a single-center male cohort of 14 PO individuals and 15 matched healthy control (HC) individuals, we acquired diffusion tensor imaging data (anisotropy, diffusivity, and fiber tracking) in literature-based regions of interest (prefrontal cortex, anterior cingulate cortex, amygdala, and corpus callosum). We trained a linear support vector machine to discriminate between PO and HC individuals using these WM microstructure data. Post hoc, we investigated the PO model decision scores with respect to sociodemographic (age, education, and IQ) and forensic characteristics (psychopathy, sexual deviance, and future risk of sexual violence) in the PO subpopulation. We assessed model specificity in an external cohort of 53 HC individuals. Results: The classifier discriminated PO from HC individuals with a balanced accuracy of 75.5% (sensitivity = 64.3%, specificity = 86.7%, P 5000 = 0.018) and an out-of-sample specificity to correctly identify HC individuals of 94.3%. The predictive brain pattern contained bilateral fractional anisotropy in the anterior cingulate cortex, diffusivity in the left amygdala, and structural prefrontal cortex-amygdala connectivity in both hemispheres. This brain pattern was associated with the number of previous child victims, the current stance on sexuality, and the professionally assessed risk of future sexual violent reoffending. Conclusion: Aberrant white matter microstructure in the prefronto-temporo-limbic circuit could be a potential neurobiological correlate for PO individuals at high-risk of reoffending with CSA. Although preliminary and exploratory at this point, our findings highlight the general potential of MRI-based biomarkers and particularly WM microstructure patterns for future CSA risk assessment and preventive efforts.

MEG reveals preference specific increases of sexual-image-evoked responses in paedophilic sexual offenders and healthy controls.

OBJECTIVES: Paedophilic disorder is characterised by sexual attraction towards children. Classification of a counterpart as sexually attractive likely occurs rapidly, and involves both conscious and unconscious attentional and cognitive processes. Magnetoencephalography (MEG) is an imaging method especially well-suited to examine visual and attentional processes triggered by sexual images within the range of milliseconds. METHODS: We investigated brain responses to sexual images depicting adults (frequent) and children (infrequent stimulus) in seventeen paedophilic patients with a history of child sexual offending (P + CSO) and twenty healthy controls (HC) during a passive visual oddball paradigm. Event-related fields (ERF) were measured to extract the magnetic visual mismatch negativity (vMMNm), and how it relates to the processing of different classes of sexual stimuli. RESULTS: P + CSO exhibited significantly longer vMMNm latencies (100-180 ms post-stimulus) than HC. Moreover, P + CSO showed widespread increased amplitudes in response to child images starting from P3a and P3b components and lasting up to 400 ms post-stimulus presentation localised in frontal and temporal brain regions. CONCLUSIONS: This study uncovers the first MEG differences in automatic change detection between P + CSO and HC during the presentation of subliminal sexual images of adults and children, contributing towards a better understanding of the neurobiological processes of P + CSO.

Expectation of sexual images of adults and children elicits differential dorsal anterior cingulate cortex activation in pedophilic sexual offenders and healthy controls.

BACKGROUND: Pedophilic disorder is characterized by increased sexual interest towards children, with comparatively lesser interest towards adults. In real life, the behavior of subjects with pedophilic disorder is shaped by evaluative processes in response to sexually relevant cues. Therefore, brain activation during anticipation of sexually relevant cues is of potential interest. Whereas previous research demonstrated reduced activation when viewing adult (non-preferred) sexual stimuli in pedophilic sex offenders (PSOs), it is not known if anticipation of preferred versus unpreferred stimuli will elicit differential brain activation. METHODS: Two fMRI studies (1.5 and 7 Tesla) were conducted in separate samples, each with 26 subjects (13/13 PSOs/controls) to assess brain activity during expectancy of subsequent adult (non-preferred) sexual stimuli. In the second study (7 Tesla) additionally child (preferred) cues were presented. RESULTS: As predicted, expectancy of adult sexual stimuli generated smaller dorsal anterior cingulate cortex (dACC) activation in PSOs in both studies, driven by stronger activation during expectancy of adult erotic stimuli in non-pedophilic controls (HCs). In the second study, PSOs showed significantly increased activations in dACC during expectancy of child stimuli compared with expectancy of adult stimuli. This difference was significantly greater compared to the same contrast in HCs, thus demonstrating preference specificity of dACC activation. CONCLUSION: Our findings support the notion of decreased brain activation to adult cues in PSOs and preference specificity in neural response during expectancy of erotic stimuli. The localization of these cue reactivity differences in the salience network supports the interpretation that PSOs show abnormally increased preparatory activation even before relevant sexual stimuli are actually presented.

Pedophilic sex offenders are characterised by reduced GABA concentration in dorsal anterior cingulate cortex.

A pedophilic disorder is characterised by abnormal sexual urges towards prepubescent children. Child abusive behavior is frequently a result of lack of behavioral inhibition and current treatment options entail, next to suppressing unchangeable sexual orientation, measures to increase cognitive and attentional control. We tested, if in brain regions subserving attentional control of behavior and perception of salient stimuli, such inhibition deficit can be observed also on the level of inhibitory neurotransmitters. We measured GABA concentration in the dorsal anterior cingulate cortex (dACC) and in a control region, the pregenual anterior cingulate cortex (pgACC) in pedophilic sex offenders (N = 13) and matched controls (N = 13) using a 7 Tesla STEAM magnetic resonance spectroscopy (MRS). In dACC but not in the control region pedophilic sex offenders showed reduced GABA/Cr concentrations compared to healthy controls. The reduction was robust after controlling for potential influence of age and gray matter proportion within the MRS voxel (p < 0.04). Importantly, reduced GABA/Cr in patients was correlated with lower self-control measured with the Barratt Impulsiveness Scale (p = 0.028, r = -0.689). In a region related to cognitive control and salience mapping, pedophilic sex offenders showed reduction of the inhibitory neurotransmitter GABA which may be seen as a neuronal correlate of inhibition and behavioral control.

Impaired Attentional Control in Pedophiles in a Sexual Distractor Task.

Pedophilic disorder, a subtype of paraphilia, is defined as a recurrent sexual interest in prepubescent children, which is characterized by persistent thoughts, fantasies, urges, sexual arousal, or behavior. Besides a deviant sexual preference, sexual preoccupation was found to be a dynamic risk factor for reoffending. Thus, it is conceivable that sex offenders and especially sex offenders against children have difficulties to control their responses to sexual stimuli. In the current study pedophiles, forensic and non-forensic control subjects had to solve a cognitive task, while sexual distractors were presented simultaneously. This kind of task also requires control functions. Therefore, data were analyzed with respect to attentional control while comparing eye movements toward sexual distractors and toward the cognitive task. We were mainly interested in how early (fixation latency) and late (relative fixation time) attentional processes were allocated to both, the cognitive target stimuli and the sexual distractors. Pedophiles demonstrated significantly lower attentional control in the sexual distractor task than both control groups (non-pedophiles). They showed a shorter fixation latency and longer fixation time for sexual distractors than non-pedophiles. Furthermore, pedophiles demonstrated a longer fixation latency and shorter fixation time for cognitive target stimuli. For classification analyses, an attentional control index (ACI) was built, i.e., the difference between eye movements on cognitive target stimuli and sexual distractors. For the ACI of early attentional processes, i.e., fixation latency, a good classification between pedophiles and non-pedophiles was found. We assumed that the measured attentional control represents inhibitory executive functions, specifically interference control. Further studies should examine if low attentional control in pedophiles is due to low motivation to solve the task or rather to a lack of ability to control attention with respect to sexual and/or neutral distractors. Prospectively, this design could be useful to generate hypotheses about clinical important aspects of controllability, the capacity of self-control, and the severity of a paraphilic disorder.

Increased frequency of brain pathology in inmates of a high-security forensic institution: a qualitative CT and MRI scan study.

This study aimed to assess whether brain pathology might be more abundant in forensic inpatients in a high-security setting than in non-criminal individuals. By using a previously used reliable approach, we explored the frequency and extent of brain pathology in a large group of institutionalized offenders who had not previously been considered to be suffering from structural brain damage and compare it to healthy, non-offending subjects. MRI and CT brain scans from 148 male inpatients of a high-security mental health institution (offense type: 51 sex, 80 violent, 9 arson, and 8 nonviolent) that were obtained due to headache, vertigo, or psychological complaints during imprisonment were assessed and compared to 52 non-criminal healthy controls. Brain scans were assessed qualitatively with respect to evidence of structural brain damage. Each case received a semiquantitative rating of "normal" (=0), "questionably abnormal" (=1), or "definitely abnormal" (=2) for the lateral ventricles, frontal/parietal cortex, and medial temporal structures bilaterally as well as third ventricle. Forensic inpatients displayed signs of brain damage to a significantly higher degree than healthy controls (p < 0.001). Even after adjustment for age, in the patients, being younger than the controls (p < 0.05), every offender type group displayed a higher proportion of subjects with brain regions categorized as definitely abnormal than the non-criminal controls. Within the forensic inpatients, offense type groups did not significantly differ in brain pathology. The astonishingly high prevalence of brain pathology in institutionalized inmates of a high-security mental health institution who previously had not been considered to be suffering from an organic brain syndrome raises questions on whether such neuroradiological assessment might be considered as a routine procedure in newly admitted patients. Furthermore, it highlights that organic changes, detectable under clinical routine conditions, may play a role in the development of legally relevant behavioral disturbances which might be underestimated.

High prevalence of brain pathology in violent prisoners: a qualitative CT and MRI scan study.

The aim of this study was to determine the frequency and extent of brain anomalies in a large sample of incarcerated violent offenders not previously considered neuropsychiatrically ill, in comparison with non-violent offenders and non-offending controls. MRI and CT brain scans from 287 male prison inmates (162 violent and 125 non-violent) not diagnosed as mentally ill before that were obtained due to headache, vertigo or psychological complaints during imprisonment were assessed and compared to 52 non-criminal controls. Brain scans were rated qualitatively with respect to evidence of structural brain damage. Each case received a semiquantitative rating of "normal" (=0), "questionably abnormal" (=1) or "definitely abnormal" (=2) for the lateral ventricles, frontal/parietal cortex and medial temporal structures bilaterally as well as third ventricle. Overall, offenders displayed a significantly higher rate of morphological abnormality, with the violent offenders scoring significantly higher than non-violent offenders and controls. This difference was statistically detectable for frontal/parietal cortex, medial temporal structures, third ventricle and the left but not the right lateral ventricle. The remarkable prevalence of brain pathology in convicted violent prisoners detectable by neuroradiological routine assessment not only highlights the importance of frontal and temporal structures in the control of social, and specifically of violent behaviour, but also raises questions on the legal culpability of violent offenders with brain abnormalities. The high proportion of undetected presence of structural brain damage emphasizes the need that in violent criminals, the comprehensive routine neuropsychiatric assessment usually performed in routine forensic psychiatric expertises should be complemented with brain imaging.

Diagnostic accuracy of eye movements in assessing pedophilia.

INTRODUCTION: Given that recurrent sexual interest in prepubescent children is one of the strongest single predictors for pedosexual offense recidivism, valid and reliable diagnosis of pedophilia is of particular importance. Nevertheless, current assessment methods still fail to fulfill psychometric quality criteria. AIMS: The aim of the study was to evaluate the diagnostic accuracy of eye-movement parameters in regard to pedophilic sexual preferences. METHOD: Eye movements were measured while 22 pedophiles (according to ICD-10 F65.4 diagnosis), 8 non-pedophilic forensic controls, and 52 healthy controls simultaneously viewed the picture of a child and the picture of an adult. Fixation latency was assessed as a parameter for automatic attentional processes and relative fixation time to account for controlled attentional processes. MAIN OUTCOME MEASURES: Receiver operating characteristic (ROC) analyses, which are based on calculated age-preference indices, were carried out to determine the classifier performance. Cross-validation using the leave-one-out method was used to test the validity of classifiers. RESULTS: Pedophiles showed significantly shorter fixation latencies and significantly longer relative fixation times for child stimuli than either of the control groups. Classifier performance analysis revealed an area under the curve (AUC) = 0.902 for fixation latency and an AUC = 0.828 for relative fixation time. The eye-tracking method based on fixation latency discriminated between pedophiles and non-pedophiles with a sensitivity of 86.4% and a specificity of 90.0%. Cross-validation demonstrated good validity of eye-movement parameters. CONCLUSIONS: Despite some methodological limitations, measuring eye movements seems to be a promising approach to assess deviant pedophilic interests. Eye movements, which represent automatic attentional processes, demonstrated high diagnostic accuracy.

How is informed consent related to emotions and empathy? An exploratory neuroethical investigation.

CONTEXT: Informed consent is crucial in daily clinical practice and research in medicine and psychiatry. A recent neuroethical investigation explored the psychological factors that are crucial in determining whether or not subjects give consent. While cognitive functions have been shown to play a central role, the impact of empathy and emotions on subjects' decisions in informed consent remains unclear. OBJECTIVE: To evaluate the impact of empathy and emotions on subjects' decision in informed consent in an exploratory study. DESIGN: Decisional capacity and informed consent to a subsequent imaging study were evaluated with the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR). Empathy and emotion recognition were measured with the Multifaceted Empathy Test (MET) and the Florida Affect Battery (FAB). SETTING: Psychiatric subjects were recruited from a general psychiatric hospital and a forensic state hospital. PATIENTS: A mixed group of 98 healthy men and forensic and non-forensic psychiatric subjects were investigated. RESULTS: Both empathy (MET) and emotion recognition (FAB) correlated with MacCAT-CR scores. Higher cognitive empathy and good emotion recognition (compared with low empathy and emotion recognition) were associated with increased decisional capacity and higher rates of refusal to give informed consent. CONCLUSIONS: This study shows an empirical relationship between decision-making and informed consent, on the one hand, and emotions and empathy on the other. While this study is exploratory and preliminary, the findings of a relationship between informed consent, emotions and empathy raise important neuroethical questions with regard to an emotional-social concept of informed consent and potential clinical implications for testing informed consent.

Electroconvulsive therapy in forensic psychiatry--ethical problems in daily practice.

There is a widespread similarity between diagnoses in general psychiatry compared with those found in forensic psychiatry. Consequently, forensic psychiatrists face serious cases that need to undergo treatment by electroconvulsive therapy (ECT). Although it is a well known and valid treatment, ECT is rarely applied to forensic-psychiatric patients or prisoners as well. This might be due to the general assumption that detained individuals, either in forensic psychiatry or in prisons, will not be chosen for a therapy, which is merely looked on as an emergency treatment. Besides, informed consent might be estimated not valid in such persons. However, the use of ECT in forensic psychiatry or prisons cannot be denied anymore because diagnoses and indications for ECT parallel the situation in general psychiatry. With the numbers of schizophrenic and depressive patients considerably increasing in the past years in our forensic unit, we estimate the indication for ECT in forensic psychiatry of approximately 3% and 12.5%, respectively.

Antipsychotic polypharmacy in the emergency treatment of highly aggressive schizophrenic prisoners - a retrospective study.

In past years, Zuclopenthixolacetate as well as Flupentixoldecanoate have each proven to be reliable and efficient in the treatment of schizophrenic psychoses. In a specially implemented psychiatric treatment unit (PTU) we administered a high-dose depot neuroleptic combination therapy initially consisting of both substances to seriously ill schizophrenic prisoners who exhibited highly aggressive behaviour (N=20). We initially used both antipsychotics at the same time as a simple regimen in order to restore the prisoners' health to enable them to return to their home prisons. A single coercive intervention was performed in 14 out of 20 prisoners which was followed by a second one in two cases according to Article 101 of the German Code of Criminal Procedure. On average, prisoners needed a treatment course of 30.4 days. Within this time PANSS global scores were reduced by approximately 40%. Side effects occurring as a consequence of neuroleptic treatment were negligible and could be dealt with.

Neurophilosophical perspectives of neuroimaging in forensic psychiatry-giving way to a paradigm shift?

Forensic psychiatry is concerned with the relationship between psychiatric abnormalities and legal violations and crimes. Due to the lack of available biological criteria, evaluation and therapy in forensic psychiatry have so far been restricted to psychosocial and mental criteria of offenders' personalities. Recent advances in neurosciences allow a closer approach to the neural correlates of personality, moral judgments and decision-making. We propose to discuss the introduction of biological criteria in the field of forensic psychiatry and to establish rules as to what extent such biological criteria will be a better and more reliable choice in judging mentally ill criminals by using all available information that can be obtained by biological means. Psychosocial and subjective criteria in forensic evaluation will be more and more accomplished by biopsychosocial and objective criteria. The responsibility of having committed a criminal act will no longer be exclusively defined by judging free and voluntary decision-making, but rather by brain-behavior relationships. What is often referred to as psychosocially determined mental processes thus could be complemented by estimating the degree of biopsychosocially determined neural processes. We conclude that such a process could contribute to a paradigm shift in forensic psychiatry, which will have profound implications for offenders, forensic psychologists and psychiatrists, the law and society in general.

Brain pathology in pedophilic offenders: evidence of volume reduction in the right amygdala and related diencephalic structures.

CONTEXT: Pedophilic crime causes considerable public concern, but no causative factor of pedophilia has yet been pinpointed. In the past, etiological theories postulated a major impact of the environment, but recent studies increasingly emphasize the role of neurobiological factors, as well. However, the role of alterations in brain structures that are crucial in the development of sexual behavior has not yet been systematically studied in pedophilic subjects. OBJECTIVE: To examine whether pedophilic perpetrators show structural neuronal deficits in brain regions that are critical for sexual behavior and how these deficits relate to criminological characteristics. DESIGN: Amygdalar volume and gray matter of related structures that are critical for sexual development were compared in 15 nonviolent male pedophilic perpetrators (forensic inpatients) and 15 controls using complementary morphometric analyses (voxel-based morphometry and volumetry). Psychosocial adjustment and sexual offenses were also assessed. RESULTS: Pedophilic perpetrators showed a significant decrease of right amygdalar volume, compared with healthy controls (P = .001). We observed reduced gray matter in the right amygdala, hypothalamus (bilaterally), septal regions, substantia innominata, and bed nucleus of the striae terminalis. In 8 of the 15 perpetrators, enlargement of the anterior temporal horn of the right lateral ventricle that adjoins the amygdala could be recognized by routine qualitative clinical assessment. Smaller right amygdalar volumes were correlated with the propensity to commit uniform pedophilic sexual offenses exclusively (P = .006) but not with age (P = .89). CONCLUSIONS: Pedophilic perpetrators show structural impairments of brain regions critical for sexual development. These impairments are not related to age, and their extent predicts how focused the scope of sexual offenses is on uniform pedophilic activity. Subtle defects of the right amygdala and closely related structures might be implicated in the pathogenesis of pedophilia and might possibly reflect developmental disturbances or environmental insults at critical periods.

Pedophilia is linked to reduced activation in hypothalamus and lateral prefrontal cortex during visual erotic stimulation.

BACKGROUND: Although pedophilia is of high public concern, little is known about underlying neural mechanisms. Although pedophilic patients are sexually attracted to prepubescent children, they show no sexual interest toward adults. This study aimed to investigate the neural correlates of deficits of sexual and emotional arousal in pedophiles. METHODS: Thirteen pedophilic patients and 14 healthy control subjects were tested for differential neural activity during visual stimulation with emotional and erotic pictures with functional magnetic resonance imaging. RESULTS: Regions showing differential activations during the erotic condition comprised the hypothalamus, the periaqueductal gray, and dorsolateral prefrontal cortex, the latter correlating with a clinical measure. Alterations of emotional processing concerned the amygdala-hippocampus and dorsomedial prefrontal cortex. CONCLUSIONS: Hypothesized regions relevant for processing of erotic stimuli in healthy individuals showed reduced activations during visual erotic stimulation in pedophilic patients. This suggests an impaired recruitment of key structures that might contribute to an altered sexual interest of these patients toward adults.