Frequency and Importance of Intelligence Diagnostics for Assessment and Treatment in Forensic Psychiatry According to Sec. 64 StGB (German Criminal Code)

Background: The psychiatric treatment of patients with intellectual disability generally takes more time and involves more obstacles than the treatment of patients with normal intelligence. To date, this has received little consideration in the forensic psychiatric treatment of criminals with substance use disorders. Therefore, in the present study, the data from n = 145 offenders with substance use disorder in accommodation in accordance with Section 64 of the Criminal Code were evaluated. Methods: The intelligence quotient was determined using the Wechsler Adult Intelligence Scale (R) - Fourth Edition (WAIS-IV). In addition to socioeconomic data, the total scores of the Psychopathy Checklist - Revised (PCL-R) and the Level of Service Inventory - Revised (LSI-R) were collected. Results: More than two thirds of those examined had intelligence below the normal range. Patients with intellectual disability were older, had a higher criminal history and had a poorer legal prognosis. Among the patients without a school diploma, only 3 % achieved an intelligence quotient within the normal range. Conclusions: Forensic- psychiatric experts should therefore regularly carry out an intelligence diagnosis in the initial assessment if there is no school leaving certificate. Although further research on patients with intellectual disability appears to be necessary, the implications regarding poorer prognosis and longer time requirements for therapy in the treatment of this group should be given greater importance.