Imprisonment, alcohol dependence and risk of delusional disorder: a cross-sectional study

Background: Compared to the general population, an excess of psychotic illnesses, major depression and dependence disorders among prisoners has been reported. However, the impact of prison on detainees' psychopathology has rarely been studied.

Objective: To determine the mental disorders liable to develop or regress on entry into prison and over time.

Method: Two samples of French prisoners detained in local prisons were interviewed using the same methodology. The first sample consisted of 267 new arrivals. The second was a random sample of 450 prisoners. Diagnoses were assessed using a thorough methodology: each prisoner was interviewed for approximately 2 hours by two clinicians. One of the clinicians used a structured clinical interview, which generates DSM IV diagnoses (MINI plus v 5.0); the second completed the procedure with an open clinical interview. The final DSM IV diagnoses were obtained as a consensus between the two approaches. Multilevel logistic regressions were used to take into account potential confounders.

Results: Prevalence rates of mental disorders were substantially higher in prison even for the sample of newcomers (major depression disorder: 24.7%, substance dependence: 17.6% and schizophrenia: 4.1%). Alcohol dependence disorder was significantly more frequent in the sample of newcomers (OR 1.84 [1.01-3.51]). No significant difference was evidenced between samples for substance dependence disorder. Psychotic disorders were significantly less frequent at entry into prison, particularly delusional disorder (OR 0.29 [0.08-0.98]).

Conclusion: This study shows the contrasted potential effects of prison on psychopathology: alcohol dependence disorders were significantly more frequent for the newcomers, while the frequency of delusional disorders was lower. This evidence is arguing in favour of the validity of the old concept: prison psychosis. Moreover, prisoners should receive relevant help from clinicians to cope with these disorders.