Two intravenous infusions of ketamine (0.5 mg/kg) given 24 hours apart, added to usual treatment, led to full remission of suicidal ideas by day 3 in 63.0% of hospitalized patients with suicidal ideation, compared to 31.6% with placebo. The benefit was strongest in patients with bipolar disorder (odds ratio 14.1), not significant in those with depressive disorder (odds ratio 1.3), and intermediate for other disorders (odds ratio 3.7). At six weeks, remission remained high in the ketamine group (69.5% vs 56.3%) but was no longer statistically significant. Side effects were limited, with no manic or psychotic symptoms observed. An analgesic effect on mental pain may explain the anti-suicidal action.
The Australian Therapeutic Goods Administration (TGA) imposed specific conditions on the use of MDMA and psilocybin for therapeutic purposes: only psychiatrists who are trained and authorized to prescribe these substances may do so, each patient case must be approved by a human research ethics committee, and the treatments must be combined with psychotherapy. Additionally, a TGA officer and the ethics committee must confirm that a suitably robust treatment protocol has been developed.
A single 25 mg dose of psilocybin, given with psychological support, reduced depression scores more than a 1 mg control dose over 12 weeks in 233 patients with treatment-resistant depression. The 10 mg dose showed intermediate effects. Participants received the drug in calming, non-clinical rooms with a therapist present during the eight-hour psychedelic session and then returned home. The results suggest that psilocybin can be a useful treatment for this difficult-to-treat condition.