Background: Behavioural activation (BA) is effective in adults with depression but the evidence for young people (YP) is less clear. We therefore developed and tested a new coproduced BA programme. Method: In phase one (2014 to 2015 inclusive), we codeveloped with young people attending specialist child and adolescent mental health service (CAMHS) an 8-session BA workbook. In Phase two (2019 to 2020 inclusive), we ran an uncontrolled feasibility study in two specialist CAMHS, with BA being offered to YP by less specialised staff.Results: In phase one, we tested the workbook with 15 YP with depression and other comorbidities. Satisfaction was good from both YP and staff, and 9 YP reported improvement in mood. In phase two, 51 YP were offered BA; 15 declined to take part. 36 consented with three dropping out after consent. 33 YP (mean age 14.6, 12 males, 24 females) continued treatment attending a mean of 6.6 sessions. At the end of treatment, youth-rated Mood and Feeling Questionnaire (MFQ) mean score decreased from 43.2 to 27.6, difference 14.6 (95% CI 8.7 to 20.2; n = 28), and Clinician Global Assessment Score (CGAS) mean score increased from 52.3 to 69.8, difference 18.0 (95% CI 11.9 to 24.2; n = 29). Of the 33 YP who participated in therapy, 12 (36%) recovered and were discharged. Conclusions: This programme demonstrated preliminary evidence for effectiveness and utility. Less specialised staff were able to use BA, and this may reduce secondary waits for more specialist therapy. More research is needed about the role of BA in specialist CAMHS.

Objective To identify genes underlying childhood onset psychosis. Methods Patients with onset of psychosis at age 13 or younger were identified from clinics across England, and they and their parents were exome sequenced and analysed for possible highly penetrant genetic contributors. Results We report two male childhood onset psychosis patients of different ancestries carrying hemizygous very rare possibly damaging missense variants (p.Arg846His and p.Pro145Ser) in the L1CAM gene. L1CAM is an X-linked Mendelian disease gene in which both missense and loss of function variants are associated with syndromic forms of intellectual disability and developmental disorder. Conclusions This is the first study reporting a possible extension of the phenotype of L1CAM variant carriers to childhood onset psychosis. The family history and presence of other significant rare genetic variants in the patients suggest that there may be genetic interactions modulating the presentation.