Psychedelics for treating psychiatric disorders: Are they safe?

A meta-analysis of 5 RCTs of MDMA-assisted therapy for PTSD in adults demonstrated that MDMA was well-tolerated, and few serious adverse events were reported.²⁸ Two trials from 2018 that were included in this meta-analysis—Mithoefer et al²⁹ and Ot’alora et al³⁰—illustrate the incidence of specific adverse effects. In a randomized, double-blind trial of 26 veterans and first responders with chronic PTSD, Mithoefer et al²⁹ found the most commonly reported reactions during experimental sessions with MDMA were anxiety (81%), headache (69%), fatigue (62%), muscle tension (62%), and jaw clenching or tight jaw (50%). The most commonly reported reactions during 7 days of contact were fatigue (88%), anxiety (73%), insomnia (69%), headache (46%), muscle tension (46%), and increased irritability (46%). One instance of suicidal ideation was severe enough to require psychiatric hospitalization (this was the only instance of suicidal ideation among the 106 patients in the meta-analysis by Bahji et al²⁸); the patient subsequently completed the trial. Transient elevation in pulse, blood pressure, and body temperature were noted during sessions that did not require medical intervention.²⁹ Ot’alora et al³⁰ found similar common adverse reactions: anxiety, dizziness, fatigue, headache, jaw clenching, muscle tension, and irritability. There were no serious adverse effects.

While the use of MDMA in controlled interventional settings has resulted in relatively few adverse events, robust literature describes the risks associated with the nonclinical/recreational use of MDMA. In cases of MDMA toxicity, death has been reported.³¹ Acutely, MDMA may lead to sympathomimetic effects, including serotonin syndrome.³¹ Longer-term studies of MDMA users have found chronic recreational use to be associated with worse sleep, poor mood, anxiety disturbances, memory deficits, and attention problems.³² MDMA has also been found to have moderate potential for abuse.³³

Ketamine/esketamine

Ketamine is a dissociative anesthetic with some hallucinogenic effects. It is an N-methyl-d-aspartate (NMDA) antagonist frequently used in anesthesia, and it can induce a state of sedation, immobility, pain relief, and amnesia. In low doses, ketamine is used off-label to treat major depressive disorder and treatment-resistant depression. Most clinical trials of ketamine for depression have dosed IV ketamine from 0.5 to 1 mg/kg 1 to 3 times a week. It can also be administered as an IM, intranasal, oral, subcutaneous, or sublingual formulation.³⁴

Esketamine, the S(+)-enantiomer of ketamine, is also an NDMA antagonist. It has been developed as an intranasal formulation, typically dosed between 56 and 84 mg 2 times a week for 1 month, once a week for the following month, and once every 1 to 2 weeks thereafter.³⁵ In most ketamine and esketamine trials, these compounds have been used without psychotherapy, although some interventions have integrated psychotherapy with ketamine treatment.³⁶

Bennett et al³⁷ elaborated on 3 paradigms for ketamine treatment: biochemical, psychotherapeutic, and psychedelic. The biochemical model examines the neuro­biological effects of the medication. The psychotherapeutic model views ketamine as a way of assisting the psychotherapy process. The psychedelic model utilizes ketamine’s dissociative and psychedelic properties to induce an altered state of consciousness for therapeutic purposes and psychospiritual exploration.

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