Study designs of evaluations included in the review
Only RCTs that were double-blind were included in the review.
Specific interventions included in the review
Hypericum extract alone: 900 mg 0.3% hypericin per day (in three divided doses), 500 mg 0.5% hypericin per day (in two divided doses), and 1800 mg 0.3% hypericin per day (in three divided doses). The comparators were placebo, imipramine, maprotiline or amitriptyline.
Participants included in the review
Patients with a depressive disorder. Patients were aged 19 to 75 years (mean 47 years). They were recruited from a range of settings, including psychiatry, neurology, general practice and internal medicine clinics.
Outcomes assessed in the review
The main outcome was the number of responders to treatment, where responder is defined as a patient whose total score according to the Hamilton Rating Scale for Depression (HAMD) has fallen either to an absolute value of less than 10, or to a value that is less than 50% of their baseline score. One study did not use this definition of responder, but did utilise the HAMD scores. Mean HAMD scores were also assessed. Side effects and severe adverse events were also assessed.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.