How Ketamine Dose and Treatment Length Relate to Internalizing Mental Health Disorders

Intramuscular doses of racemic ketamine at 0.5 and 1.0 mg/kg produced robust effects on outcome scales for internalizing disorders.

• Patients with treatment-resistant depression, post-traumatic stress disorder, generalized and/or social anxiety, or obsessive-compulsive disorder were assessed.
• Effects were most pronounced 24 hours after dosing and decreased significantly by 168 hours.
• No significant difference in the magnitude of change was observed between the doses of 0.5 mg/kg and 1.0 mg/kg at either time point.
• The response to ketamine did not differ significantly among the various internalizing disorders at 24 hours.
• Combining these findings with existing data suggests ketamine may have a narrow inverted-U dose-response profile, peaking between 0.5 and 1.0 mg/kg.

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