Efficacy and tolerability of St. John's wort extract LI 160 versus imipramine in patients with severe depressive episodes according to ICD-10

Abstract

The special extract of St. John's wort, LI 160, exhibited a superior antidepressant efficacy compared to placebo in several controlled trials. Two further trials demonstrated a similar reduction of depressive symptomatology under LI 160 compared to tricyclics. All these trials were performed in mildly to moderately depressed patients. The present investigation was a randomized, controlled, multicentre, 6-week trial comparing 1800 mg LI 160/die to 150 mg imipramine/die in severely depressed patients according to ICD-10. The main efficacy parameter, a reduction of the total score of the Hamilton Depression Scale, proved both treatment regimens very effective at the end of the 6 week treatment period (mean values 25.3 to 14.5 in the LI 160 group and 26.1 to 13.6 in the imipramine group), but not statistically equivalent within a a-priori defined 25% interval of deviation. The analysis of subgroups with more than a 33% and 50% reduction of the HAMD total score justified the assumption of equivalence within a 25% deviation interval. This view was also supported by the global efficacy ratings from patients and investigators. Regarding adverse events, the nonrejection of the nonequivalence hypothesis denotes a superiority of the herbal antidepressant. These main result indicate that LI 160 might be a treatment alternative to the synthetic tricyclic antidepressant imipramine in the majority of severe forms of depressions. However, more studies of this type must be performed before a stronger recommendation can be made.