St. John’s Wort or Celexa for Minor Depression?
Minor depression is defined in various ways. DSM-IV lists it as a disorder for further study, and defines it as a depressive episode of at least two weeks’ duration that includes two or more criteria of major depressive disorder. Whether minor depression responds to antidepressant medication is up for debate, with few studies yielding mixed results. For this reason, any new study of minor depression is worth reviewing.
In this latest U.S. placebo-controlled double blind study, 81 patients with “minor depression” were randomized to either 810 mg/day of St. John’s Wort (29 DEPRESSION participants), 20 mg/day of citalopram (Celexa) (27 participants), or placebo (25 participants) for 12 weeks. Minor depression was defined differently from the DSM-IV version, namely, by the presence of two to four symptoms of major depression for at least six months, but no more than two years. Thus, these are patients who fit diagnostically somewhere between DSM-IV “minor depression” and “dysthymia.”
After early drop-outs, 73 patients were evaluated. On the primary outcome measure, which was reduction in the score on the Inventory of Depression Symptomology—Clinician rated (IDSC), there were no significant differences among the treatment groups. Treatment response rates were: St. John’s Wort, 38.5%, Celexa, 41.7%, and placebo, 52.2% (not statistically different) (Rapaport MH et al, J Psychiatric Res 2011;45:931–941).
TCPR’s Take: While the study was too small to detect all but very large treatment differences, the fact that the placebo response was so high in this group is intriguing. It implies that mildly depressed patients with few depressive criteria are unlikely to respond better to medications than to unspecified factors such as the passage of time or the expectation of improvement. More research is needed, since depressed patients who fall between the diagnostic cracks seem to be quite common in clinical practice.