Introduction:
Catatonia, documented since the 19th century, remains a significant challenge in terms of recognition and treatment. Over the last two decades, ketamine has brought new perspectives to psychiatry, sparking widespread interest. Concurrently, catatonia has attracted heightened scientific attention. Preliminary evidence suggests the therapeutic potential of ketamine for catatonia.

Methods:
We systematically searched Medline/PubMed, Embase, PsycINFO, Lilacs, and Cochrane Library databases, as well as Google Scholar, for studies with ketamine or its enantiomers as intervention for catatonia, with no restrictions to underlying diagnosis, date, language, or study design.

Results:
Twenty articles were included, encompassing a total of 25 catatonic patients receiving ketamine or esketamine. Predominantly female (61.9 %), with a mean age of 44.4 years, patients mostly exhibited manifestations compatible with the retarded subtype of catatonia. Mood disorders were the most prevalent underlying diagnoses. Ketamine was primarily administered intravenously over a 40-minute period and in multiple-dosing schemes. Mean response and remission rates of catatonic manifestations for the whole sample were 80 % and 44 %, respectively, with no reports of worsening catatonic features or psychotic symptoms. Only one patient discontinued treatment due to intolerable dissociative effects.

Conclusion:
Challenging the conventional contraindication of ketamine in psychotic disorders, current evidence highlights its potential efficacy, particularly in treating catatonia. Pending further research, we advocate reevaluating this contraindication, as it may offer a promising therapeutic option, especially for challenging cases. Preliminary evidence suggests potentially greater benefits for catatonic patients with underlying mood disorders compared to primary psychotic disorders.