EFFECTS OF KETAMINE AND ESKETAMINE ON SUICIDAL IDEATION WITHIN THE FIRST 24 HOURS IN ADULTS WITH DEPRESSIVE DISORDERS: VARIABILITY IN CLINICAL FINDINGS AND INTERPRETATIVE CHALLENGES - A NARRATIVE REVIEW

Background: Ketamine and esketamine have been studied as rapid-acting interventions in adults with depressive disorders and suicidal ideation, but findings vary across populations, settings, comparators, routes, and outcome measures.

Aim: To examine their effects on suicidal ideation within the first 24 hours and to identify factors contributing to variability across studies.

Methods: This narrative review used a structured PubMed and Scopus search for English-language studies published from January 2000 through April 30, 2026. Clinical trials and relevant secondary studies were considered. No formal risk-of-bias assessment or quantitative synthesis was performed.

Results: Intravenous ketamine studies reported rapid reductions in suicidal ideation, although findings were inconsistent. One midazolam-controlled trial showed a 4.96-point greater reduction in the Scale for Suicide Ideation score at 24 hours, whereas another found no significant difference in the primary Beck Scale for Suicide Ideation outcome. Intranasal esketamine added to intensive standard-of-care treatment improved depressive symptoms at 24 hours, but clinician-rated suicidality did not differ significantly between groups in either ASPIRE trial.

Conclusions: Intravenous ketamine may rapidly reduce suicidal ideation in selected adults. Intranasal esketamine has shown clearer early effects on depressive symptoms than on suicidality-specific outcomes. Standardized measures and longer follow-up are needed.