Antidepressants do work in depression while evidence for cognitive behavioural yherapy is poorer say experts

May 7 2008

A new revision of clinical guidelines to help doctors manage patients with depression has challenged the rationale behind the UK government's policy of rolling out of cognitive behavioural therapy (CBT) for milder depression.

According to a comprehensive review of treatments for depression, there is a lack of evidence for CBT being more helpful than other forms of psychological support in mild depression or for its efficacy in severe depression. There is also good evidence for antidepressants being effective in depression, with benefit increasing the more severe the depression. This is contrary to recent reports that antidepressants don't work except in the most severe depression.

Dr Ian Anderson, Senior Lecturer and Honorary Consultant Psychiatrist, Neuroscience and Psychiatry Unit, University of Manchester, UK, says the cost effectiveness of CBT should be thoroughly investigated before it is adopted more widely because it is likely to be offered to people with milder depression where the evidence is poorest.

"There is often not a level playing field in considering evidence for drugs versus psychological treatment, especially in milder depression," Dr Anderson explains, adding that specific psychological treatments are relatively expensive compared to drug treatments because treatment involves training of the therapists as well as the costs of administering the intervention.

To measure the effectiveness of these treatments requires "comparison against appropriate control treatment like non-specific supportive treatment in the same way drugs are compared against placebo," says Dr Anderson. "This is important given the rolling out of CBT for milder depression - probably less expensive means of support are more cost-effective."

This conclusion is just one of the issues to emerge from a comprehensive review of the evidence for various forms of management of depression, conducted as part of a revision of the 2000 British Association for Psychopharmacology evidence-based guidelines, and published this week by SAGE in the Journal of Psychopharmacology. The aim of the review was to incorporate new evidence and to update the recommendations where appropriate.

Revisions to the guidelines were agreed after a consensus meeting involving experts in depressive disorders and their management, user representatives, and medical and scientific staff from pharmaceutical companies in May 2006 and a subsequent literature review.

The new guidelines also question whether CBT should routinely be combined with antidepressant medication for depression in adolescents-as the UK's National Institute for Health and Clinical Excellence suggests-citing a lack of evidence. Dr Anderson says some recommendations run contrary to NICE guidance:

• First, the choice between antidepressants and CBT needs to be individually decided rather than routinely recommending CBT first.
• Second, combining CBT with antidepressants should not be routine.

He suggests that doctors should try to adopt a more dimensional approach to depression rather than over-emphasising categories of disease severity such as "not depressed", "clinical depression", etc, or relying too heavily on cut-off points such as simply counting symptoms. It is important to consider an individual patient's situation in a more rounded fashion such as past history, degree of impairment, duration of symptoms and risk of relapse.

"Overall, the guidelines clear up some issues and alter the emphasis on certain treatments for example suggesting that for subthreshold depression, which is not of clinical severity, antidepressants should be considered if it lasts more than 2-3 months," Dr Anderson says. "We have also challenged the idea that antidepressants need to be given more than once a day or that for most antidepressants you need to follow a long tailing off before starting a new antidepressant."

"We hope [the guidelines] will set a standard. We have tried to be practical in our advice and addressed issues that other guidelines tend not to be specific about such as managing side-effects of antidepressants. We want to help doctors and patients choose treatments and strategies that have the best chance of helping," Dr Anderson concludes.