Results for behavioural activation are overstated

The study by Moradveisi et al,¹ which is applicable to both secondary mental health and primary care, looks at the prospect of using minimally trained staff in delivering behavioural activation against pharmacological intervention in the treatment of severe depression. We would like to highlight the following points for further clarification.

First, an obvious problem of the study was the lack of a placebo arm, which would have lent credibility. As the cultural avoidance of antidepressants in Iran has been highlighted, adding a placebo group would have removed some bias such as paying for medication in the treatment as usual (TAU) group after 3 months and also in the analysis.

Second, sertraline was used at a suboptimal dose and was slowly titrated, against prevailing practice. A meta-analysis shows an optimum dose for sertraline between 100 and 150 mg/day - doses below the therapeutic range were significantly less effective, i.e. by 7%.² Sertraline reached its lowest therapeutic dose of 100 mg at 6 weeks. All drop-outs occurred before the mid-point assessment and only three were as a result of medication side-effects.

Third, there was a significant difference in the amount of attention that participants received in each group. Participants in the behavioural activation group received 50% more face-to-face sessions than the TAU group. The study did not adjust for this in the analysis.

Fourth, last observation carried forward (LOCF) was used in the study. However, 5% of drop-outs occurred in the behavioural activation group as opposed to a significant 30% from the TAU group. Last observation carried forward is used frequently in intention-to-treat studies but standard errors and confidence intervals from LOCF underestimate uncertainty.³ As there are no strategies for universal use, reasons for the choice of a certain method have to be provided when designing and analysing clinical trials.⁴ Last observation carried forward analysis seems to have favoured the behavioural activation group.

Many other limitations of the study are cited in the paper itself. Significant numbers of participants were recruited via advertisement or word of mouth, which seemed to have attracted more women and perhaps more psychologically minded individuals. It would have been helpful to include these advertisements as a supplement to the paper in order to identify any bias.

Finally, we wondered whether an ethics committee would allow this type of study to go ahead in the UK as it included individuals with severe depression. In England and Wales, before recruitment to a trial, potential participants must be assessed under the Mental Capacity Act 2005; in Scotland, the Adults with Incapacity (Scotland) Act 2000 (para. 72) must be used.⁵ Since the authors of the study state that ‘the study's aim was to investigate whether a simple psychological treatment […] would be a viable alternative to antidepressant medication […] in a non-Western country’, we are unsure of an equivalent law in Iran and whether this criterion was met.