Evaluating a brief imagery-based intervention for adolescent depression: study protocol for a Phase IIB randomised...

There is an urgent need for psychological interventions that can target depression in late adolescence and prevent it from having lifelong implications. Schools have been identified as a promising setting to enhance access to interventions and offer support earlier. We have co-developed a novel intervention, IMAGINE, that targets key cognitive mechanisms implicated in depression across the lifespan. Depression has been associated with distressing negative mental images, a deficit in positive future images and overgeneral autobiographical memories. Interventions targeting these factors have shown clinical promise in adults. Here, we combine techniques targeting these cognitive processes into a novel, brief psychological intervention for adolescent depression. This Phase IIb randomised controlled trial will evaluate IMAGINE compared to an active psychological intervention.

One hundred sixty adolescents (aged 16-18) with high levels of depressive symptoms will be recruited from schools. Participants will be randomly allocated to IMAGINE or the active psychological control intervention, non-directive support (NDS). Assessment will take place at baseline, 8-, 16- and 24-week post randomisation. The primary objective is to establish whether IMAGINE reduces symptoms of depression, relative to NDS, at 8 weeks following randomisation. Secondary objectives include whether changes in depression are maintained at 16- and 24-week follow-up, the efficacy of IMAGINE on secondary clinical outcomes and key cognitive mechanisms and, finally, to assess outcomes around acceptability, safety and adherence.

If IMAGINE is shown to be safe and clinically effective, an effectiveness-implementation hybrid RCT will be indicated. If rolled out as an intervention, IMAGINE would significantly extend the range of effective therapies available for adolescent depression.

ISRCTN, ISRCTN14015295. Registered 11 September 2023, https://doi.org/10.1186/ISRCTN14015295 .