Table 1.
Summary of clinical studies evaluating the antidepressant effect of psilocybin (n = 6). The abbreviations are explained in the footer.
| Authors | Year | Type of Study | Sample Size | Characteristic of Participants | Intervention | Results | Conclusions | QATQS Global Rating |
|---|---|---|---|---|---|---|---|---|
| Grob et al. [24] | 2011 | RCT | 12 | Subjects with depression and anxiety and advanced-stage cancer | Psylocybin in two sessions in several weeks interval (0.2 mg/kg) with 250 mg of niacin as a placebo As an efficacy measure BDI, STAI-S, STAI-T, Profile of Mood States (POMS) were used | BDI score were reduced at 6 months after treatment, STAI-T score reduction was observed at 1 and 3 months after treatment | Use of psilocybin combined with psychotherapy may provide an alternative treatment especially in the conditions with minimal response to conventional therapies, which needs to be investigated further in RCTs | 1 |
| Griffiths et al. [25] | 2016 | RCT | 51 | Subjects with depression or/and anxiety associated with life-threatening cancer | Psilocybin 22 or 30 mg/70 kg (high-dose) or placebo 1 or 3 mg/70 kg (low-dose) administered in controlled conditions in two sessions in 5 weeks interval. The effects were measured in GRID-HAM-D-17 scale and HAM-A assessed with the SIGH-A | Participants who get the high dose of psilocybin showed more significantly clinical response and symptom remission in GRID-HAM-D-17 and in HAM-A scale comparing to those patients who got low-dose therapy, those effects were sustained 6 months after treatment | Psilocybin decreases depressed mood as well as anxiety and also increase the quality of life in patients with a life-threatening cancer, the more various population of patients should be examined to evaluate the generality of psilocybin treatment | 1 |
| Carhart-Harris et al. [26] | 2016 | Non-RCT (open-label trial) | 12 | Subjects with treatment-resistant major depressive disorder (MDD) | Psylocybin 10 mg and 25 mg in two sessions with 7 days interval. Effects were assessed with QIDS-SR, Beck Depression Inventory (BDI), STAI, Snaith Hamilton Pleasure Scale (SHAPS), HAM-D, Montgomery-Asberg Depression Rating Scale and Global Assessment of Functioning (GAF) | BDI scores were reduced at 1 week, 3 and 6 months after treatment, STAI and SHAPS scores were reduced 1 week and 3 months after treatment, HAM-D and MADRS scores were reduced 1 week after treatment | Psilocybin is in need for further investigations in double-blind RCT as it seems to be effective in fighting drug-resistant MDD | 3 |
| Carhart-Harris et al. [27] | 2018 | Follow-up, Non-RCT (open-label trial) | 20 | Subjects with treatment-resistant major depressive disorder (MDD) | Psylocybin 10 mg and 25 mg in two sessions with 7 days interval. Effects were assessed with QIDS-SR (mainly) Beck Depression Inventory (BDI), STAI, Snaith Hamilton Pleasure Scale (SHAPS), HAM-D and Global Assessment of Functioning (GAF) | In 19 patients who completed all assesment time points, QIDS-SR16 scores were significantly reduced, BDI and STAI scores were reduced at 1 week, 3 and 6 months after treatment (p < 0.001), SHAPS scores were reduced at 1 week and 3 months after treatment (p < 0.001) and HAM-D and GAF scores were reduced 1 week after treatment (p < 0.001). No serious side-effects were observed during the treatment | Psilocybin is a promising tool in fighting unresponsive MDD and needs further investigations in double-blind RCT | 3 |
| Ross et al. [28] | 2016 | RCT | 29 | Subjects with depression and anxiety in life-threatening cancer | Psylocybin in two sessions (0.3 mg/kg) with a 7 days interval combined with psychotherapy and niacin (250 mg) as placebo. Efficacy was measured via STAI-T and STAI-S, HADS-A, HADS-D, HADS-T, BDI | Significant differences between study and control group, reductions on STAI-T, STAI-S, HADS-A( 58% vs. 14%), HADS-T, HADS-D and BDI (83% vs. 14%) in 1 day, 2, 6, and 7 weeks after first psylocybine session | In combination with psychotherapy in life-threatening illness psilocybin contributes to quick and sustained anti-depressant and anxiolytic effects | 2 |
| Davis et al. [29] | 2020 | RCT | 24 | Subjects with major depressive disorder (MDD) | Psilocybin 1 session 20 mg/70 kg, 2 session 30 mg/70 kg with supportive psychotherapy. Effects were evaluated in Hamilton Rating Scale for Depression (HAM-D) and in the Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR) | After the session with psilocybin 71% of patients in 1 week and in 4 weeks showed more than 50% reduction in GRID-HAM score, 58% of participants in 1 week and 54% of participants in 4 weeks met the criteria of remission of depression; in QIDS-SR scale after psilocybin session the rapid, large decrease in mean depression score were observed which was remained 4 weeks after the treatment | Sessions with psilocybin-assisted therapy demonstrated large and sustained antidepressant effects among patients with MDD, however still further placebo-controlled studies are needed | 1 |
QATQS—Quality Assessment Tool for Quantitative Studies, RCT—randomized controlled trial, Non-RCT—non- randomized controlled trial, MDD—major depressive disorder, MADRS—Montgomery-Åsberg Depression Rating Scale, HAM-D—Hamilton Rating Scale for Depression, HAM-D—Hamilton Rating Scale for Anxiety, QIDS-SR Quick Inventory of Depressive Symptomatology-Self-Report, BDI—Beck’s Depression Inventory, STAI-S—State-Trait Anxiety Inventory State, STAI-T—State-Trait Anxiety Inventory Trait, SHAPS—Snaith Hamilton Pleasure Scale, GAF—Global Assessment of Functioning, POMS—Profile of Mood States, HADS-A—Hospital Depression and Anxiety Scale-Anxiety, HADS-D—Hospital Depression and Anxiety Scale-Depression, HADS-T—Hospital Anxiety and Depression Scale-Total, SIGH-A—Structured Interview Guide for the Hamilton Anxiety Scale.