A feasibility randomised controlled trial of a brief early intervention for adolescent depression that targets emotional mental images and memory specificity (IMAGINE).

Brief, evidence-based interventions for adolescent depression are urgently required, particularly for school-settings. Cognitive mechanisms research suggests dysfunctional mental imagery and overgeneral memory could be promising targets to improve mood. This feasibility randomised controlled trial with parallel symptomatic groups (n = 56) compared a novel imagery-based cognitive behavioural intervention (ICBI) to non-directive supportive therapy (NDST) in school settings. Blind assessments (of clinical symptoms and cognitive mechanisms) took place pre-intervention, post-intervention and follow-up three months later. The trial aimed to evaluate the feasibility and acceptability of the methodology and interventions, and estimate the likely range of effects of the intervention on self-reported depression. The pre-defined criteria for proceeding to a definitive RCT were met: full recruitment occurred within eleven months; retention was 89%; ICBI acceptability was above satisfactory; and no harm was indicated. Intention-to-treat analysis found large effects in favour of ICBI (relative to NDST) at post-intervention in reducing depressive symptoms (d = -1.34, 95% CI [-1.87, -0.80]) and improving memory specificity (d = 0.79 [0.35, 1.23]), a key cognitive target. The findings suggest that ICBI may not only improve mood but also strengthen abilities associated with imagining and planning the future, critical skills at this life stage. A fully powered evaluation of ICBI is warranted. Trial Registration: https://www.isrctn.com/; ISRCTN85369879.