Psilocybin, an Effective Treatment for Major Depressive Disorder in Adults – A Systematic Review
Summary & key facts
Researchers reviewed six clinical studies that tested psilocybin as a treatment for adults with major depressive disorder. Altogether about 320 people took part. In every study, psilocybin was given along with psychological support and was linked to clear reductions in depressive symptoms and few reported side effects. The studies were small and used different methods, and the authors say more, larger studies and a standard way to give the drug and therapy are needed before we can know how well it really works.
- The review combined six clinical studies that looked at psilocybin for major depressive disorder.
- About 320 people took part across all the studies.
- Half of the studies were randomized controlled trials and half were open-label, meaning some were more tightly controlled than others.
- Every study included psychological support as part of the treatment when psilocybin was given.
- All six studies found that psilocybin reduced depressive symptoms compared with before treatment or with control groups in those trials.
- The studies reported few side effects from psilocybin in their samples.
- The authors note that psilocybin acts on serotonin receptors involved in mood, which is one possible reason it can affect depression.
- Because the total number of people studied was still small and the methods varied, the authors call for more, larger studies and for standard rules about session timing and the type of psychological support.
- The review also warns that there may be publication bias, meaning studies with positive results may be more likely to be published than negative ones, so the current picture could be incomplete.
Abstract
Psilocybin is a classical psychedelic which has been utilised for healing purposes for millenia. However, with its classification as a Schedule I substance, research into this compound is scarce with few FDA-approved clinical studies. Despite this, profound findings into its antidepressant effects (largely through its action on 5-HT1a receptors) in mental illnesses such as major depressive disorder have rapidly increased interest back into their potential therapeutic benefits. This systematic review provides an analysis of the studies examining the clinical use of psilocybin for major depressive disorder. In total 6 studies were selected, including 319 participants, with half being randomised controlled trials and half open label trials. In every study psychological support was included as an integral part of the treatment. It was found that every study significantly favoured the use of psilocybin in reducing depressive symptoms, with few side effects. This gives psilocybin an advantage over commonly prescribed selective serotonin reuptake inhibitors (SSRIs), which carry more risk and cause more adverse effects. This drug therefore shows promise for being used as a clinical treatment for major depressive disorder, however future research should develop a paradigm for its use, with the timing of sessions and type of psychological support specified to allow for more precise analysis of the clinical effects of the drug. Additionally, more studies into its clinical efficacy are needed for appropriate detection of any publication bias. With this, psilocybin could prove to be revolutionary in treating depression and become an alternative medication to SSRIs.
