Latest research on the value of cognitive behavioral therapy includes a systematic review by an Oxford University team that explores the distinction between the closely associated effects of relieving depression and improving self-esteem.

The central aim of cognitive behavioral therapy (CBT) is to modify a person’s broad perception of him or herself and the world. It teaches individuals suffering from depression to analyze their negative thoughts, assumptions, evaluations and beliefs in order to bring into focus a more accurate and positive set of judgments.

There’s plenty of research to suggest CBT is a powerful treatment. And it seems logical that somehow brightening the perceptual filter through which one sees one's life might relieve depression. Tatiana L. Taylor and Paul Montgomery at the Centre for Evidence-Based Intervention, looked for existing research that tested the idea that the root of depression is a dark image of oneself – and that CBT has the power to brighten it.

They were particularly interested in studies that examined the relationships between depression, CBT treatment, and self-esteem in adolescents. Unfortunately, they found only two that had the right kind of data to address their question. Combining the evidence from the two studies yielded information on 82 people who applied to participate in CBT interventions. Both studies compared individuals who actually received the therapy to similar individuals on a waiting list for a CBT program.

This rather slight evidence base suggested that CBT is quite effective in reducing depressive symptoms and in boosting participants’ confidence in their academic ability (but not necessarily their global self worth). Although these are somewhat promising results, the authors did not look at whether participants’ self-esteem increased as their depression decreased. The data simply showed that CBT helps both to relieve depression and to boost academic self-esteem. It is not clear that such a boost caused the reduction in depression.

Certainly more research is needed to determine the key ingredients in CBT. If it works by improving self image, then prevention programs that help teenagers to see themselves more clearly might be particularly helpful.

• See also: Judging the dose to ward off the blues

Summary of “Can cognitive-behavioral therapy increase self-esteem among depressed adolescents? A systematic review “ by Tatiana L. Taylor and Paul Montgomery in Children and Youth Services Review, Volume 29, Issue 7, July 2007, pp823-839