The aim of this systematic review was to assess the efficacy of homeopathic remedies (HRs) in the treatment of mental disorders.
Italian psychiatrists performed a Medline/Embase search for studies written in English and published from any date to October 23, 2018. All randomized controlled trials enrolling patients with any psychiatric disorder and comparing HR with placebo, no treatment, or other psychotropic drugs were included.
A total of 212 studies were screened, 9 met all selection criteria and reported data on major depressive disorder (MDD) (n = 4), generalized anxiety disorder (n = 1), attention-deficit/hyperactivity disorder (n = 2), and premenstrual syndrome/dysphoric disorder (n = 2). Eight of 9 randomized controlled trials showed high risk of bias. Homeopathy showed greater efficacy in MDD compared with fluoxetine, and in premenstrual syndrome/dysphoric disorder compared with placebo, whereas no difference emerged between homeopathy and placebo in MDD and attention deficit/hyperactivity disorder.
The authors concluded that the available data on homeopathy in psychiatric disorders are insufficient to support their use in clinical practice.
In their discussion section, they also add an interesting note of caution: Ethical considerations should therefore prevent clinicians from recommending HRs, which have a cost either for patients or for health care systems, until when a sufficient amount of solid evidence becomes available. In addition, systematic reviews of randomized trials, if unavailable, are advisable for all medical conditions for which homeopathy is currently prescribed.
This is a rigorous, transparent and clear review which generates no surprises. Few critical thinkers would have expected a positive result. It also teaches us, I think, a valuable lesson about the difference between a rigorous and a flimsy review, between independent and biased research. In 2011, evidently pro-homeopathy authors published a paper of the latter kind. Here is its abstract:
Objective: To systematically review placebo-controlled randomized trials of homeopathy for psychiatric conditions.
Data sources: Eligible studies were identified using the following databases from database inception to April 2010: PubMed, CINAHL, PsycINFO, Hom-Inform, Cochrane CENTRAL, National Center for Complementary and Alternative Medicine grantee publications database, and ClinicalTrials.gov. Gray literature was also searched using Google, Google Scholar, the European Committee for Homeopathy, inquiries with homeopathic experts and manufacturers, and the bibliographic lists of included published studies and reviews. Search terms were as follows: (homeopath* or homoeopath*) and (placebo or sham) and (anxiety or panic or phobia or post-traumatic stress or PTSD or obsessive-compulsive disorder or fear or depress* or dysthym* or attention deficit hyperactivity or premenstrual syndrome or premenstrual disorder or premenstrual dysphoric disorder or traumatic brain injury or fibromyalgia or chronic fatigue syndrome or myalgic encephalitis or insomnia or sleep disturbance). Searches included only English-language literature that reported randomized controlled trials in humans.
Study selection: Trials were included if they met 7 criteria and were assessed for possible bias using the Scottish Intercollegiate Guidelines Network (SIGN) 50 guidelines. Overall assessments were made using the Grading of Recommendations Assessment, Development and Evaluation procedure. Identified studies were grouped into anxiety or stress, sleep or circadian rhythm complaints, premenstrual problems, attention-deficit/hyperactivity disorder, mild traumatic brain injury, and functional somatic syndromes.
Results: Twenty-five eligible studies were identified from an initial pool of 1,431. Study quality according to SIGN 50 criteria varied, with 6 assessed as good, 9 as fair, and 10 as poor. Outcome was unrelated to SIGN quality. Effect size could be calculated in 16 studies, and number needed to treat, in 10 studies. Efficacy was found for the functional somatic syndromes group (fibromyalgia and chronic fatigue syndrome), but not for anxiety or stress. For other disorders, homeopathy produced mixed effects. No placebo-controlled studies of depression were identified. Meaningful safety data were lacking in the reports, but the superficial findings suggested good tolerability of homeopathy. A funnel plot in 13 studies did not support publication bias (χ(2)(1) = 1.923, P = .166).
Conclusions: The database on studies of homeopathy and placebo in psychiatry is very limited, but results do not preclude the possibility of some benefit.
The two conclusions speak for themselves, I think. They should remind us that, although systematic reviews are in principle the most reliable source of evidence, it is still necessary to check the quality of the work and the independence of the worker.