Passiflora for anxiety disorder.

BACKGROUND: Anxiety is a very common mental health problem in the general population and in the primary care setting. Herbal medicines are popularly used worldwide and could be an option for treating anxiety if shown to be effective and safe. Passiflora (passionflower extract) is one of these compounds.

OBJECTIVES: To investigate the effectiveness and safety of passiflora for treating any anxiety disorder.

SEARCH STRATEGY: The following sources were used: electronic databases: Cochrane Collaboration Depression, Anxiety and Neurosis Cochrane Controlled Trials Register (CCDANCTR-Studies), Medline and Lilacs; Cross-checking references; contact with authors of included studies and manufacturers of passiflora.

SELECTION CRITERIA: Relevant randomised and quasi-randomised controlled trials of passiflora using any dose, regime, or method of administration for people with any primary diagnosis of general anxiety disorder, anxiety neurosis, chronic anxiety status or any other mental health disorder in which anxiety is a core symptom (panic disorder, obsessive compulsive disorder, social phobia, agoraphobia, other types of phobia, postraumatic stress disorder). Effectiveness was measured using clinical outcome measures such as Hamilton Anxiety Scale (HAM-A) and other scales for anxiety symptoms.

DATA COLLECTION AND ANALYSIS: Two reviewers independently selected the trials found through the search strategy, extracted data, performed the trial quality analyses and entered data. Where any disagreements occured, the third reviewer was consulted. Methodological quality of the trials included in this review was assessed using the criteria described in the Cochrane Handbook. For dichotomous outcomes, relative risk with 95% confidence intervals (CI) were calculated, and for continuous outcomes, weighted mean difference with 95%CI was used.

MAIN RESULTS: Two studies, with a total of 198 participants, were eligible for inclusion in this review. Based on one study, a lack of difference in the efficacy of benzodiazepines and passiflora was indicated. Dropout rates were similar between the two interventions. Although the findings from one study suggested an improvement in job performance in favour of passiflora (post-hoc outcome) and one study showed a lower rate of drowsiness as a side effect with passiflora as compared with mexazolam, neither of these findings reached statistical significance.

AUTHORS' CONCLUSIONS: RCTs examining the effectiveness of passiflora for anxiety are too few in number to permit any conclusions to be drawn. RCTs with larger samples that compare the effectiveness of passiflora with placebo and other types of medication, including antidepressants, are needed.