St John's wort (Hypericum perforatum) fresh plant tincture for patients with mild to moderate depression - a prospective observational study.

Background: High-dosed dry extract preparations of St John's wort (Hypericum perforatum) (hd-SJW) are equally effective as synthetic antidepressants for mild to moderate depression as shown by various randomised controlled trials (RCTs). Other available preparations of SJW such as fresh plant tinctures are dosed lower and no clinical study about their effect has been published so far.

Objectives: To evaluate the effect of a SJW fresh plant tincture (C-SJW-ft) on depressive symptoms and its tolerability in patients comparable to patients reported in hd-SJW RCTs applying the same outcome, the Hamilton Depression Scale 17 (HAM-D17).

Methods: Prospective observational study of outpatients with mild to moderate depressive episodes (ICD-10/DSM-IV) treated with C-SJW-ft. Outcomes were HAM-D17 decline between inclusion and 6 weeks (42 days ±7 days), percentage of responders, (>50% decline), and frequency and type of adverse events. Descriptive analysis was performed. From a systematic literature review of RCTs of hd-SJW applying HAM-D17 as efficacy outcome at 6 weeks, the characteristics of the included patient population and the outcomes were extracted for comparison (rRCTs ["reference RCTs"]).

Results: 52 evaluable patients were included, 1 patient dropped out (switch to synthetic antidepressants), of the 51 (per protocol [PP] "expanded") patients, 42 completed the second HAM-D 17 within 42 ± 7 days (PP "strict"). The included patient population was comparable to the 10 identified rRCTs with hd-SJW for age (51/50.6 years [mean, pp strict/pp expanded], 40.2-51.4 years [mean, rRCTs] and gender (76%/75% female [pp strict/pp expanded], 54-86% [rRCTs]). The baseline HAM-D17 was slightly lower (PP strict: 16.4 [mean, range 9-28]; PP expanded 16.9 [9-28) compared to rRCTs (19.7-22.8). The decline of HAM-D17 in patients treated with C-SJW-ft (baseline/end of observation period) was 49% (PP strict) and 52% (PP expanded) comparable to the decline of 45-59% in the rRCTs of hd-SJW; likewise, responders were 50% and 57% compared to 42-70%. Adverse events were lower (4%) compared to 20-39% in the rRCTs.

Conclusion: In an observational prospective patient cohort with mild to moderate depressive episodes corresponding to patients included in RCTs of hd-SJW, applying the same efficacy outcome and timeframe, C-SJW-ft showed comparable effects and good tolerability. Further clinical trials seem justified.