Parker (Reference Parker2001) expertly reviews the evidence for efficacy and effectiveness of different classes of antidepressants. In particular, he addresses the issue of whether selective serotonin reuptake inhibitors (SSRIs) are less efficacious in melancholia; reviews effectiveness studies; examines why there is a discordance between efficacy studies and clinical observation; and reviews the implications of differential effectiveness.

An additional important area that should be considered is that of gender differences in treatment response to antidepressants. Recent evidence has arisen to suggest that women may have a better response to SSRIs and men a better response to tricyclic antidepressants (Reference Kornstein, Schatzberg and ThaseKornstein et al, 2000). As depression is approximately twice as common in women than in men, gender differences of this nature are important and should be considered when reviewing this area. The reasons for this difference may be related to the effects of female sex hormones on serotonergic neurotransmission and in particular on the function of the 5-HT_1A receptor (Reference Young, Dow and GoodwinYoung et al, 1993). The evidence for gender differences in treatment response to antidepressant is not definitive (Reference Kornstein, Schatzberg and ThaseKornstein et al, 2001; Reference Quitkin, Stewart and McGrathQuitkin et al, 2001) and further studies are needed to fully establish the validity of this notion. However, there are potentially important implications, and in the future clinical management strategies may take account of gender differences in treatment response.