Assessing the effect of multidimensional family therapy in adolescents on police arrests against a background of falling crime rates. A randomised controlled trial with 7-year follow-up

Background: Earlier, we reported that multidimensional family therapy (MDFT) and cognitive behavioural therapy (CBT) decreased criminal offending in adolescents as measured with self-report in a randomised controlled trial with 1-year follow-up. The present study tested if this effect could be confirmed using police arrest data. Methods: Study participants were 109 adolescents who were recruited for the Dutch part of a transnational treatment trial. National police arrest records were analysed for 3 years before the adolescents entered treatment with MDFT or CBT and for 7 years after treatment entry. Results: Police arrest rates rose in the 3 years preceding treatment and then dropped in both treatment groups to almost zero level during the follow-up period. Conclusions: The results suggest that MDFT and CBT both strongly and durably decreased police arrest rates. However, this conclusion remains uncertain as crime rates concurrently decreased in the general population. Trial registration: ISRCTN51014277