Author: Neil Stewart
Position: Consultant Psychiatrist
Institution: Hertfordshire Partnership NHS Trust
E-mail: neilstewa@gmail.com
Submitted Date: February 26, 2008
Published Date: February 26, 2008
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

I wonder whether the effect size of antidepressants may have been underestimated in this metaanalysis by the sole inclusion of relatively short trials . Thirty three of the trials were six weeks in duration , six were of four weeks duration , two of five weeks duration and six of eight weeks duration .
The recent STAR*D( ref 1) trail showed that a response ( a 50 % reduction in QIDS-SR16 scores ) to citalopram in MDD took on average 6 weeks and remission ( a score of 7 or less on the HAMD or 5 or less on the QIDS-SR16 ) took on average 7 weeks to achieve .

It is quite possible , therefore , that the trials lasting six weeks and less would miss those patients who would , had they remained on antidepressants for longer , have responded or remitted .

I suspect that trials that compare antidepressants against placebo for longer periods , of say three months , are required to address with confidence the difference between placebo and antidepressants in major depressive disorder .

Ref Trivedi MH . Evaluation of outcomes with citalopram using measurement based care in STAR*D : implications for clinical practice . Am Journal of Psychiatry 2006:163:28-40