Axis I psychiatric disorders (PD) and substance use disorders (SUD) are common in prison, but only few studies have focused on their association in this setting. Dual diagnosis (DD) (the co-occurrence of a SUD and any axis I disorder) is known to have a poorer prognosis and to require more intense supportive care.Objectives
The objectives of this study were (1) to describe prisoners with DD (prevalence and characteristics); (2) to compare DD prisoners with 3 other groups of prisoners: no diagnosis (ND), SUD alone, or other isolated PD; and (3) to evaluate the impact of DD on suicide risk in prison.Method
A random stratified strategy was used to select 23 various types of prisons and 998 prisoners. Diagnoses were assessed using a unique procedure, each prisoner being evaluated by 2 psychiatrists, 1 junior, using a structured interview (MINI 5 plus), and 1 senior, using an open clinical interview. Following interviews, clinicians met to establish a list of diagnoses. Cloninger's temperament and character inventory was also used.Results
Of the prisoners, 26.3% had a DD. DD prevalence was almost 80% in prisoners with SUD, while only one-third of the prisoners with an axis I PD had co-morbid SUD. No significant differences were observed in drug use patterns between DD and SUD without co-morbid PDs. DD showed the strongest association with suicide risk [OR = 5.7 (1.7–4.6)].Conclusion
DD is very frequent in prison and is a major risk factor for suicide. Systematic psychiatric/SUD screening of prisoners with either a SUD or an axis I PD should be encouraged.