BackgroundMore treatment for substance misuse should be provided within prisons.AimsTo examine differences between prisoners on remand with substance misuse problems and other prisoners on remand.MethodRandom selection and interview of unconvicted male prisoners (n=750, a 9.4% sample), plus examination of the prison medical record.ResultsOf the sample of 750, 253 subjects (33.7%) reported either drug- or alcohol-related health problems or dependency. Compared with other prisoners on remand, they reported more childhood adversity, conduct disorder, self-harm, past psychiatric treatment and current mood disorder, and had fewer qualifications, were more likely to be unemployed and have more housing difficulties.ConclusionsOne-third of unconvicted men in prison report substance-related problems, and these are a marker for vulnerability within a disadvantaged population. Health care providers should involve this group in treatment and rehabilitation, both inside prison and following release.