Admission to a psychiatric hospital is a strong predictor for future adverse outcome such as imprisonment and death. There exists a large gender gap for this relationship for men and women.

To study sex difference in the time from admission to psychiatric hospital and time to imprisonment or death.

All patients over 18 years of age admitted for the first time to psychiatric in-patient care in a nationwide population were found through administrative registers in Iceland. A Cox proportional hazard ratio was calculated for a composite outcome variable of either imprisonment or death for 10 years following admission.

During a 27-year period, a total of 4,459 individuals were admitted to psychiatric services in Iceland out of which 2,303 were men (51.6%). The average age at first admission was 25.9 ± 5.7 for men and 25.8 ± 5.8 for women (p=0.64). Substance use disorder was the most common discharge diagnosis in 46% of admissions, mood disorder in 35.6%, personality disorder in 12.8% and schizophrenia and related disorders in 7.9%. A Cox proportional hazard model showed a hazard ratio (HR) of adverse outcome for men 2.52 (95%-confidence interval (95%-CI): 1.87–3.39, p>0.001). HR for substance use disorder was 3.08 (95%-CI: 2.31-4.11), personality disorders HR = 1.85 (95%-CI: 1.34-2.55), whereas older age at admission was protective HR 0.96 (95%-CI: 0.93-0.98, p=0.003) as was admission later in the period HR 0.96 (95%-CI: 0.93-0.98).

Men have a statistically worse prognosis when looking at hard endpoints such as imprisonment and death.