AbstractAimHeroin‐dependent adolescents demonstrate high rates of comorbid psychological problems. Among heroin‐dependent adults, opiate substitution treatment (OST) programmes appear to reduce mental health problems. We sought to examine the impact of OST on psychological well‐being in adolescents, as this is unknown.MethodsWe conducted a prospective study examining psychological well‐being in heroin dependent adolescents, aged 18 years or younger, engaged in outpatient psychologically supported OST. Patients were treated with either methadone or buprenorphine. This was complimented with individual key working, counselling (motivational interviewing and cognitive behavioral therapy) and group work focusing on life skills. The Beck Youth Inventory was used to measure psychological well‐being at treatment entry and repeated after 4 months of treatment.ResultsAmong 55 consecutive treatment episodes, we examined the 32 episodes where the patient persisted with the OST programme. Polysubstance use was the norm at treatment entry. At follow‐up, the median doses of methadone and buprenorphine were 50 mgs and 8 mgs, respectively. Only three patients were treated with antidepressant medication. There was significant improvement in the mean depression (65.0 to 57.9, P = 0.001), anxiety (61.7 to 57.0, P = 0.006) and anger (57.8 to 54.6, P = 0.009) subscale scores. The self‐concept and disruptive behaviour subscale scores did not improve significantly.ConclusionIn this relatively short‐term follow‐up, psychosocially assisted OST appears to be associated with improved psychological well‐being in heroin‐dependent adolescents, especially in the area of depressive and anxiety symptoms.