Substance use and post-traumatic stress disorder are the two most prevalent Axis 1 disorders in the international prison population, but the boundary between being a victim or a perpetrator is often blurred because of exposure to violence, trauma, and substance use. Symptoms associated with trauma and substance use make these individuals one of the most challenging in the criminal justice system. Substance use and mental health issues have been estimated to be roughly 2–4 times greater among those with histories of childhood trauma. Women offenders report greater use of the most harmful drugs, and have higher rates of PTSD than male offenders. Racially minoritised individuals are less likely to use substances than their white counterparts and this is despite being at greater risk of drug use because they often live in disadvantaged and deprived areas.

Treatment perspectives on trauma and substance use are discussed. This concludes by arguing that an integrated approach to treatment, consisting of formulating and targeting the interplay between trauma, substance use, and offending is indicated as being the most effective way forward.

Finally, three personal narratives are included to illustrate the stories of individuals who have lived experience of the interconnection between trauma, substance use, and offending.