Cognitive behavioral therapy prevents depression in at-risk adolescents

Garber J, Clarke G, Weersing V, Beardslee W, Brent D, Gladstone T, et al. Prevention of depression in at-risk adolescents: a randomized controlled trial. JAMA 2009;301:2215-24.

Question 

Among children at risk for development of depression (on the basis of family history), does a group cognitive behavioral (CB) prevention program prevent the onset of depression compared with usual care?

Design 

Multicenter randomized controlled trial.

Setting 

Four centers in the United States

Participants 

A total of 316 years children (aged 13-17) of parents with current or prior depressive disorders. Adolescents had a history of depression, current elevated but subdiagnostic depressive symptoms, or both.

Intervention 

CB prevention program (8 weekly, 90-minute group sessions followed by 6-monthly continuation sessions) versus usual care alone.

Outcomes 

Rate and hazard ratio (HR) of a probable or definite depressive episode (ie, depressive symptom rating score of ≥4) for at least 2 weeks, as diagnosed by clinical interviewers.

Main Results 

The rate and HR of incident depressive episodes were lower for those in the CB prevention program than for those in usual care through the post-continuation period (21.4% vs 32.7%; HR, 0.63; 95% confidence interval [CI], 0.40- 0.98, number needed to treat = 9). Adolescents in the CB prevention program also showed significantly greater improvement in self-reported depressive symptoms than those in usual care (coefficient, −1.1; z = −2.2; P = .03). Current parental depression at baseline moderated intervention effects (HR, 5.98; 95% CI, 2.29-15.58; P = .001). Among adolescents whose parents were not depressed at baseline, the CB prevention program was more effective in preventing onset of depression than usual care (11.7% vs 40.5%; HR, 0.24; 95% CI, 0.11-0.50, number needed to treat = 4), whereas for adolescents with a currently depressed parent, the CB prevention program was not more effective than usual care in preventing incident depression (31.2% vs 24.3%; HR, 1.43; 95% CI, 0.76-2.67).

Conclusions 

The CB prevention program had a significant prevention effect on the basis of both clinical diagnoses and self-reported depressive symptoms, but this effect was not evident for adolescents with a currently depressed parent.

Commentary 

This is one of the few studies to show a convincing and substantial long-term reduction in depression after a preventive intervention, although most studies previously have been of primary prevention. This study combines selective and indicated prevention with relapse prevention, but with 87% to 88% participants having had a previous depressive episode, it is predominantly a study of relapse prevention. The placebo response rate in depressive disorder can be as high at 70%, and previous research has shown that a pill placebo can be as effective as cognitive behavioral therapy. In this study, the placebo effect has not been addressed. The control group did not receive a control intervention, so that it is unclear whether the effect shown was due to the cognitive behavioral intervention or whether a simpler intervention that generated a similar expectation of effect would suffice. This is an important distinction because training (for the cognitive behavioral intervention) is potentially more expensive and more difficult to implement than a simpler intervention. Despite these concerns, Garber et al have shown that episodes of depression can be reduced in young people who have suffered from depression with a relatively straightforward intervention. This is a significant advance on previous work. The challenge now is to take these findings, identify the critical active components, and work out how these may best be delivered to maximize benefit. Given the cost of depression to individuals and to society, as well as the relatively low number needed to treat in this study, this is a worthy quest.