Addiction, depression, anxiety and antisocial personality disorder may share common biological mechanisms and changes in impulsivity may contribute to the characterization of different clinical phenotypes.

Our aim was to identify diagnostic profiles in a sample of inmates in a Portuguese prison.

We examined a sample recruited at Paços de Ferreira Penitentiary Centre (n=89). Diagnosis was performed using the International Neuropsychiatric Interview (MINI). Six Version of Addiction Severity Index – European version (EuropASI) and the Psychopathy Checklist –Revised (PCL-R) were used to assess the severity of drug addiction and the presence of psychopathy.

Drug misuse was found in 61.8% of the studied subjects according to MINI. A high prevalence of psychiatric comorbidity was detected, with antisocial personality disorder (70.9%), depression (30.9%), and anxiety (32.7%) being the most common disorders. The total PCL-R score was 24. 1 (SD 8.8), 36 prisoners presented a diagnosis of psychopathy (PCL-R>30). The presence of depression in addicted individuals is associated with a lower severity of dependence (p <0.05) and lower PCL-R scores (p <0.05). The presence of addiction and depression reduces the risk of violent crime, whereas the presence of psychopathy (PCL-R> 30) increases (OR = 3.87, p <0.05).

Psychiatric disorders and addiction were successfully evaluated. Depression is associated with a lower addiction severity. The different types of psychiatric diagnoses produce a modulation in the frequency of violent crimes. The prevalence of psychiatric comorbidity underscores the advantages of a structured psychiatric assessment in prison inmates in order to provide the best treatment.