A systematic review published in this week's BMJ concludes that the many psychosocial or psychological interventions tested so far in trials do not effectively prevent postnatal depression.1 Because this is an important disorder arising from around one in eight births, the authors call for more research on intensive support at home in the postnatal period.1 As little as 20 years ago, however, there was debate about whether postnatal depression was an important problem at all. It was too often dismissed as only a minor, transient problem with coping. So what happened in the meantime to warrant these trials of possible prevention?

In 1989 the prevalence of depression among women eight months after birth in population based surveys in Victoria, Australia, was 15.4% (95% confidence interval 12.8% to 18.0%)2 and two subsequent studies found very similar prevalences and confidence intervals.3 4^w1 Depression was defined in these studies as a score of3 13 on the Edinburgh postnatal depression scale: a score of 10-12 out of a possible total score of 30 is sometimes used …