Ketamine for Bipolar Depression: A Systematic Review

Summary & key facts

Researchers looked at six experimental studies testing intravenous ketamine given along with mood stabilizers for bipolar depression. Across the studies, 135 people took part, about half were female and the average age was about 45. About 60% of the people who got ketamine had a big drop in depressive symptoms, compared with about 5% who got a placebo. Some people had short-lived dissociation after the infusion, and two people developed manic symptoms (one on ketamine and one on placebo). The authors say the results are promising but still preliminary, and more studies are needed to know about longer-term effects and other ways of giving ketamine.

Key facts:

• The review included six experimental studies with a total of 135 people. About half were women and the average age was about 45 years.
• All studies used a standard dose of 0.5 mg per kg of body weight of intravenous racemic ketamine given in addition to a mood-stabilizing medicine.
• People in the ketamine groups received between 1 and 6 doses, depending on the study.
• A treatment response was defined as at least a 50% drop in depression scores. About 61% of people who got ketamine met that definition, compared with about 5% who got placebo.
• Response rates in individual studies ranged from roughly 52% to 80% for people who got ketamine.
• Ketamine was generally reasonably well tolerated, but some participants had strong dissociative symptoms about 40 minutes after the infusion in two trials.
• Two participants developed manic symptoms during the studies: one who received ketamine and one who received placebo.
• The authors describe the evidence as preliminary and say more research is needed to check long-term safety and to test other ketamine formulations or ways of giving it.

Abstract

BACKGROUND: Ketamine appears to have a therapeutic role in certain mental disorders, most notably unipolar major depressive disorder. However, its efficacy in bipolar depression is less clear. This study aimed to assess the efficacy and tolerability of ketamine for bipolar depression. METHODS: We conducted a systematic review of experimental studies using ketamine for the treatment of bipolar depression. We searched PubMed, MEDLINE, Embase, PsycINFO, and the Cochrane Central Register for relevant studies published since each database's inception. We synthesized evidence regarding efficacy (improvement in depression rating scores) and tolerability (adverse events, dissociation, dropouts) across studies. RESULTS: We identified 6 studies, with 135 participants (53% female; 44.7 years; standard deviation, 11.7 years). All studies used 0.5 mg/kg of add-on intravenous racemic ketamine, with the number of doses ranging from 1 to 6; all participants continued a mood-stabilizing agent. The overall proportion achieving a response (defined as those having a reduction in their baseline depression severity of at least 50%) was 61% for those receiving ketamine and 5% for those receiving a placebo. The overall response rates varied from 52% to 80% across studies. Ketamine was reasonably well tolerated; however, 2 participants (1 receiving ketamine and 1 receiving placebo) developed manic symptoms. Some participants developed significant dissociative symptoms at the 40-minute mark following ketamine infusion in 2 trials. CONCLUSIONS: There is some preliminary evidence supporting use of intravenous racemic ketamine to treat adults with bipolar depression. There is a need for additional studies exploring longer-term outcomes and alterative formulations of ketamine.

Topics

Bipolar Disorder and Treatment Treatment of Major Depression Tryptophan and brain disorders

Categories

Health Sciences Medicine Pharmacology

Tags

Bipolar disorder Clinical psychology Cognition Depression (economics) Economics Ketamine Macroeconomics Medicine Psychiatry Psychology

Substances

Ketamine

Conditions & symptoms

Depression Sadness or low mood