To the Editor: There has been considerable debate about whether selective serotonin reuptake inhibitors (SSRIs) can induce suicidal thoughts and behaviour. Using data from the 2007 National Survey of Mental Health and Wellbeing (NSMHWB),1,2 we examined the relationship between SSRI use and suicidality.

The NSMHWB was a nationally representative household survey of 8841 individuals aged 16–85 years. Respondents were interviewed face-to-face and they provided information to assess whether they met International Classification of Diseases (10th revision) criteria for a lifetime affective disorder, and had symptoms in the previous year; had experienced suicidality in the previous year; and had used SSRIs (and/or other psychotropic medications) in the previous fortnight (and, if so, whether they had been taking them for < 1, 1–2, 3–5 or > 5 months).

We restricted our analyses to the 555 individuals with symptoms of an affective disorder in the previous year, and examined their suicidality over that year. In our first analysis, we compared those who had used SSRIs in the previous 2 weeks and had been taking them for any duration (n = 109) with those who had not used SSRIs in the previous 2 weeks (n = 446 [respondents in this group were not asked whether they had taken SSRIs at any other time]). Secondly, we compared the subgroup who had been taking SSRIs for more than 5 months (n = 80) with the same non-user group we used in the first analysis. In both analyses, SSRI users were no more likely than non-users to have seriously thought about suicide, made a suicide plan or made a suicide attempt (Box).

These findings are consistent with two recent systematic reviews of studies of SSRI use and attempted or completed suicide.3,4 Our study results add to their findings because we considered a fuller range of suicidal thoughts and behaviour. Although the reviews concurred with our findings with respect to adults, they found some evidence for SSRI use increasing the risk of suicidality among children and adolescents.

The NSMHWB had limitations, including a potential for recall and misclassification bias, and its inability to account for all possible confounders. Importantly, its cross-sectional nature precluded determining whether an individual’s SSRI use preceded or followed his or her suicidality. By restricting our second analysis to SSRI users who had used SSRIs for more than 5 months, we increased the likelihood that SSRI use occurred first, but we could not determine this conclusively. This would have been a problem had we found an association, because we could not infer the direction of causality. However, with no association demonstrated causality becomes a moot point.

Our findings support the contention that SSRI use in adults with affective disorders is not associated with suicide risk. Nonetheless, clinical judgement is required in prescribing SSRIs.