Reductions in criminal convictions after addiction treatment: 5-year follow-up.

Changes in criminal convictions were investigated among 1075 clients admitted to 54 drug misuse treatment services across England as part of the National Treatment Outcome Research Study (NTORS). Convictions data during the year prior to treatment, and at 1 year, 2 years, and 5 years after treatment intake were collected from the Home Office Offenders' Index, a national database of all convictions in adult and youth courts. Clinical data were collected by face-to-face interviews at intake to treatment, and at follow-up 1 year, 2 years, and 4-5 years after admission to treatment. During the year prior to treatment, 34% of the sample had been convicted of at least one offence. Conviction rates at all follow-up points were significantly lower than at intake. During the year prior to the 5-year follow-up, 18% of the sample had been convicted of at least one offence. Statistically significant reductions in the mean number of convicted offences were also found between treatment intake and 5-year follow-up. Reductions in convictions were found for acquisitive, drug selling, and violent crimes. Reductions in crime were associated with reductions in regular heroin use, age, and with stable housing. The results replicate previously reported findings of crime reductions among the NTORS cohort as indicated by self-reported measures of offending behaviour. The observed reductions in crime among drug misusers after treatment represent substantial changes in behaviour and have considerable personal, social and clinical significance. Reduced criminality also provides substantial economic benefits to society.