Mental and Physical Health Problems Before and After Detention: A Matched Cohort Study

Background: Individuals with poor health are largely overrepresented in prison populations. However, it remains unclear whether their poor health status already exists prior to their detention or reflects an effect of detention. We examined the health of detainees in the year before and after their detention and compared this with the health of matched non-detainees.

Methods: In this matched cohort study, we linked national data on all persons detained in the Netherlands in 2014/2015 to electronic health records (EHR's) of a representative sample of general practitioners in the Netherlands. Participants include 952 detained persons and 4760 matched non-detained persons (matched on age, sex and general practice). Prevalence rates of health problems in the year before and after detention and odds ratios with 95% confidence intervals were calculated. Rates for a variety of physical and mental health problems are presented.

Findings: Detainees and matched controls differed statistically significant in their pre-detention health status. Compared with controls, male detainees were more likely to report psychological (odds ratio [OR] 3·64 [95% CI 3·11-4·26]), social (1·96 [1·46-2·64]), neurological (1·34 [1·02-1·76]), digestive (1·23 [1·02-1·49]), genital system-related (1·36 [1·07-1·72]), and unspecified health problems (1·32 [1·10-1·59]) in the year before their detention. For example, 43·7% of detainees and 17·6% of controls reported psychological problems in this pre-detention year. To some extent these pre-detention health differences were related to socioeconomic differences. Nevertheless, after taking these characteristics into account, a number of pre-detention health differences between detainees and controls remained statistically significant. No statistically significant changes in prevalence rates from pre- to post-detention and no differences in the levels of change across detainees and controls were observed. For female detainees a similar pattern was found.

Interpretation: People who experience detention have high and complex health needs both pre- and post-detention. While this study did not show a health deteriorating effect of detention, it also did not show a health improving effect. This latter finding may indicate a missed opportunity for health care services to address detainees' health, especially since persons entering detention have elevated health problems. Knowledge on detainees' specific health problems may help health care providers in prisons and in the community to adequately address the health care needs of this vulnerable group.

Funding: None.