For antisocial personality disorder (ASPD), there has long been no treatment whose benefit could be cleanly demonstrated. A large study from England and Wales now closes that gap from an unfamiliar angle: it does the arithmetic.
The condition is marked by persistent aggression, irritability, recklessness, unreliability and a lack of remorse. In the general population it affects roughly two to three percent of adults — applied to Germany, some 1.4 to 2.1 million people. Among men convicted of violent offences, however, the share reaches up to 50 percent, and is associated with particularly serious and repeated offending. The burden on health services and the justice system is correspondingly high — as is the harm to those affected by the offences.
The MOAM trial (Mentalization for Offending Adult Males), led by King's College London, randomly assigned more than 300 men aged 21 and over with ASPD to two groups across 13 sites. One received standard probation supervision; the other received mentalization-based treatment (MBT) in addition — a structured talking therapy that trains the ability to recognise and interpret one's own thoughts and feelings as well as those of other people. The work was funded by the UK's National Institute for Health and Care Research.
Less aggression, less time in custody, lower costs
After 24 months, the team led by health economist Barbara Barrett compared the two groups — not only clinically, but across every cost falling on society: health care, criminal justice and the consequences of the offences themselves. The researchers also recorded which services for accommodation, education, employment and training the participants had used. The research questions and questionnaire were developed together with practitioners and with people who had themselves experienced prison and probation.
The result: the therapy group was less aggressive, as measured by the Overt Aggression Scale–Modified, and at the same time generated lower costs — a combination health economists call dominance. On average, total costs to society per person over two years were around £2,000 lower, though that difference was not statistically significant. The gap in custody was clearer: an average of 4.54 months in the therapy group against 6.96 months in the comparison group. For every one-point drop in the aggression score, about £93 was saved.
The treatment itself is not expensive. It cost an average of £826 per participant, comparable to other community-based psychological programmes — an outlay offset by shorter periods in custody and offences that did not happen.
The health-economic analysis was published in the journal PLOS One. It complements the clinical findings of the same trial, which showed that the treated men were less aggressive and less likely to reoffend. For probation services and the courts, that is a rare configuration: a programme that helps the people treated, protects those who would otherwise be harmed, and places no extra burden on the public purse.