The dark side of universal prevention: Limited effectiveness and harmful effects of classroom-based CBT in preventing adolescent depression

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Depression is a common problem in adolescence, with statistics showing that around 20% of young people will go through at least one clinically depressive episode by the age of 18 years. Given the significant impairment and deleterious consequences of depression, sustained efforts have been dedicated to preventive and early intervention.

In a recent large trial in Health Technology  Assessment, Stallard and collaborators (2013) aimed to investigate the clinical effectiveness and cost-effectiveness of a classroom-based cognitive behavioral therapy (CBT) curriculum, for depressive symptoms in high risk adolescents, as compared to the schools’ usual curriculum  of Personal, Social and Health Education (PSHE) and an attention control condition. The classroom-based CBT programme was the Resourceful Adolescent Programme (RAP-UK), which had demonstrated efficiency in reducing depressive symptoms in three previous studies and was adapted for the UK context and tested in a pilot trial. The trial was registered as ISRCTN19083628.

Methods

Cluster randomised trials are frequently used in school-based research, where classrooms or even whole schools are randomised, rather than individuals

Cluster randomised trials are frequently used in school-based research, where classrooms or even whole schools are randomised, rather than individuals

The study was a pragmatic cluster randomised controlled trial (meaning that groups of individuals, not individuals themselves get randomised) conducted in schools in the UK. Classroom-based CBT was delivered during PSHE lessons in schools by trained facilitators and was compared over a 12-month period with the regular PSHE curriculum and an attention control PSHE conditions. Assessments were completed by participants themselves and as such were not blind.

Participants were adolescents with ages between 12 and 16 years in year groups 8 to 11 in secondary schools in the UK. A pilot phase was carried out in one school for 4 year groups and 833 students. The main trial was realized in eight schools for 28 year groups and 5,671 students. Randomization was done by year group, balanced for number of classes, students, PSHE lesson frequency and scheduling.

The study looked at the following outcomes:

  • Primary outcome: symptoms of depression at 12 months assessed with the Short Mood and Feelings Questionnaire (SMFQ). Young people identified as “at risk” on the basis of the SMFQ prior to the intervention were the focus of the primary analysis
  • Secondary outcomes: anxiety, self-esteem, thoughts of personal failure, sense of connectedness to the school, bullying, substance misuse and self-harm
  • An economic analysis was also carried out considering the cost per child of delivering the intervention, quality of life and health service usage

Results

  • Of the 5,030 participants, 1064 (21.2%) were classified as high risk.

Primary outcome:

This research highlighted the potential harmful effects of classroom-based CBT, compared with conventional PHSE

This research highlighted the potential harmful effects of classroom-based CBT, compared with conventional PHSE

  • In the high risk group, SMFQ scores decreased overall at 12 months,  but there was no difference between trial arms. Adjustment for variables that were imbalanced at baseline revealed that classroom-based CBT had a small, but potentially harmful effect compared with usual PSHE (1.21, 95% CI 0.11 to 2.30; p = 0.031). Moreover, there was no evidence that classroom-based CBT was effective for adherent participants, defined as those who attended at least 60% of the sessions
  • For all participants (high- and low-risk group taken together), there was no evidence of an effect of classroom-based CBT of SMFQ scores at 12 months or over time
  • There was some evidence of an advantage of the CBT programme as compared to both control groups in participants who used drugs, but a negative effect compared to the usual PSHE in participants who reported self-harm behavior

Secondary outcomes:

  • For the high risk group, there was some evidence of potentially beneficial effects of classroom-based CBT on depression measured with another instrument as compared to the usual PSHE, and on self-harm thoughts at 6 months as compared to the attention control group. However, there was also evidence of deleterious effects of the CBT program on personal failure scores at 12 months
  • For all participants, there was evidence of an advantage of classroom-based CBT in bullying status at 12 months as compared to the attention control group and on cannabis use at 6 months as compared to the usual PSHE. Nonetheless, the CBT program was less helpful than the usual PSHE for panic symptoms, personal failure scores and general anxiety and less useful than the attention control condition for panic symptoms at 6 months

Economic analysis:

  • Analysis of cost-effectiveness using two methods (incremental cost-effectiveness ratios and cost-effectiveness acceptability curves) confirmed that classroom-based CBT was not cost-effective relative to the control groups. For most cost-effectiveness analyses, CBT ranged as more expensive and less efficient in the cost-effectiveness planes.

Conclusions

  • Despite the use of a program previously shown as efficacious, adapted for the UK context and refined in an extensive pilot study, this large trial found limited effects for classroom-based CBT on outcomes both in the high risk group and in all participants
  • Moreover, along with some beneficial effects of the CBT programme, results also indicated consistent harmful effects for some outcomes
This trial found that classroom CBT was not a cost-effective way to prevent depression in young people

This trial found that classroom CBT was not a cost-effective way to reduce depression in young people

  • Cost-effectiveness analysis did in no way support the case for recommending classroom-based CBT as a cost-effective way of reducing depression in adolescents
  • While universal prevention programmes delivered in classrooms represent alluring alternatives in terms of convenience and reach, the authors concluded, based on  the results of the present trial, that:

Classroom-based CBT programmes aiming to prevent depression delivered in schools may not be clinically effective and indeed may increase reporting of symptoms.

Link

Stallard, P., Phillips, R., Montgomery, A.A., Spears, M., Anderson, R., Taylor, J., Araya, R., Lewis, G., Ukoumunne, O.C., Millings, A., Georgiou, L., Cook, E., Sayal, K., 2013. A cluster randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of classroom-based cognitive-behavioural therapy (CBT) in reducing symptoms of depression in high-risk adolescents (PDF). Health Technol Assess 17, vii–xvii, 1–109.