Scene-Based Psychodramatic Family Therapy (SB-PFT) is a multiple-family intervention for adolescents with behavioural problems implemented by Child Welfare Services in Spain. This intervention is aimed at promoting adolescent well-being. The aim of this study was to evaluate the effectiveness of SB-PFT in 17 trials, measuring its impact on the emotional intelligence, parental attachment, peer attachment and antisocial behaviour of 216 adolescents (109 participating in the intervention and 107 in the control group). Repeated measures ANOVAs for pretest/posttest differences and long-term growth models were estimated. In the short term, the intervention had a positive impact on emotional intelligence and had a stabilising effect on parental attachment, whereas the long-term results showed significant logarithmic growth in emotional intelligence and exponential growth in parental attachment and a decrease in antisocial behaviour. However, no changes in peer attachment were shown. This study demonstrates SB-PFT to be a potentially effective intervention for adolescents with behavioural problems and emphasises the importance of fostering emotional intelligence.