Ketamine, an NMDA antagonist used for depression, produces rapid but transient antidepressant effects primarily through acute modulation of reward circuits and a sub-acute increase in neuroplasticity. Its dissociative and psychedelic properties arise from dose- and context-dependent disruption of large-scale functional networks: disruption of the salience network accounts for dissociation, while disruption of the default-mode network accounts for the psychedelic state. In psychedelic-assisted psychotherapy, relaxing high-level beliefs with support may allow revision of pathological self-representation models, with neuroplasticity playing a permissive role. This multi-level account suggests leveraging ketamine's psychedelic properties to enhance long-term benefits.
In a double-blind randomized controlled trial, 59 patients with depression received either a high (25 mg) or placebo (1 mg) dose of psilocybin. Those given the high dose reported stronger perceived 'inner healing' effects, and within that group, higher inner healer scores predicted greater improvement in depressive symptoms two weeks later. The findings suggest that the concept of an intrinsic healing mechanism activated by psychedelics merits further scientific investigation, though the idea remains scientifically nascent.
A case series of 12 patients with treatment-resistant depression treated with a novel protocol combining ketamine injections (0.5-1.5 mg/kg intramuscularly, 5-8 sessions) and brief psychodynamic psychotherapy found that 67% responded and 58% achieved remission. Half of the patients maintained remission at 3-month and 1-year follow-ups. Ego dissolution during the third ketamine session correlated with symptom improvement and psychological insight. The results suggest that combining ketamine with psychotherapy may enhance and prolong antidepressant effects beyond ketamine alone.