Ketamine Use for Suicidal Ideation in the General Hospital: Case Report and Short Review

Suicidal behaviour among inpatients in general hospitals carries a higher risk than in the general population, and the medical environment is often harder to make physically safe than psychiatric wards. Earlier research has suggested that low-dose, subanaesthetic ketamine infusion (commonly 0.5 mg/kg) has rapid antisuicide and antidepressant effects and a safety profile that permits use even in medically ill patients. This combination of potentially fast efficacy and acceptable short-term safety motivates consideration of ketamine by consultation–liaison psychiatrists when persistent suicidal ideation cannot be managed by environmental restriction alone. Vulser and colleagues present a single-case report of intravenous low-dose ketamine used to treat persistent suicidal ideation in a patient who remained in a general medical ward after a severe suicide attempt. The report aims to document the clinical course, tolerability, and temporal relationship between ketamine infusions and standardised measures of depression, hopelessness, and suicidal ideation in this setting, and to briefly situate the case within available literature about ketamine use for acute suicidality in medically ill inpatients.

This paper is an individual case report describing clinical management and repeated assessment rather than a controlled trial. The patient was a 47-year-old woman admitted to a general hospital after a self-poisoning event with bromazepam (reported dose 1,200 mg). On arrival she had medical complications including a sacral decubitus ulcer, rhabdomyolysis and delirium; bacteremia with suspected endocarditis later prevented transfer to a psychiatric ward. Her psychiatric history included anorexia nervosa, a prior suicide attempt by poisoning at age 17, remitted alcohol dependence and recurrent depressive disorder; she had been prescribed duloxetine, olanzapine and bromazepam but was non-adherent on admission. Conservative measures in the medical ward—physical restraints and sedation with diazepam and cyamemazine—were initially required because the environment could not be made sufficiently safe while bacteremia was managed. Venlafaxine 75 mg/day was started on day 11 of admission. After multidisciplinary discussion and informed consent from the patient and her husband, the team administered intravenous ketamine at 0.5 mg/kg (noted in the record as 20 mg) infused over 40 minutes on day 12, with a second identical infusion on day 14 when only modest early changes were observed. Clinical assessments used were the Montgomery–Åsberg Depression Rating Scale (MADRS), the Beck Hopelessness Scale (BHS) and the Beck Scale for Suicidal Ideation (BSSI). Two BSSI items related to past suicide attempts were excluded because they could not change over time. An anaesthesiologist and a psychiatrist were present for infusions; vital signs (heart rate, blood pressure, oxygen saturation) were monitored before, immediately after and 4 hours after each infusion. This report therefore documents temporal changes on standardised scales and clinical course, but does not employ a control condition, blinding or inferential statistics.

Before ketamine, suicidal ideation had persisted at a high level for approximately six months and remained severe during two weeks of hospitalisation, necessitating continuous restraint and sedation that produced complications including urinary retention and worsening sacral ulcer. The first ketamine infusion (0.5 mg/kg over 40 minutes) on day 12 was well tolerated: no dissociative symptoms or blood pressure increases were observed and routine vital-sign monitoring was unremarkable. No reductions on MADRS, BHS or BSSI were detected in the first 24 hours after that infusion. By 48 hours after the first infusion there was a small decrease in MADRS scores while BHS and BSSI scores remained nearly unchanged. Because this was the first clinical improvement in two weeks, a second identical infusion was administered on day 14. Over the week following the second infusion, scores on all three scales declined markedly, reaching MADRS 3/60, BHS 3/20 and BSSI 0/38 by day 20. At that point the patient’s medical status permitted transfer to a psychiatric ward, where venlafaxine was replaced with mirtazapine 30 mg/day because of hyponatraemia. The patient was later admitted to a specialised unit for anorexia nervosa treatment. At five-month follow-up she reported no suicidal thoughts. The authors note that venlafaxine had been started only one day before the first ketamine infusion, a duration unlikely to explain the rapid clinical change, and that the patient’s low body mass index (reported as 14 kg/m2) may have contributed to the initially slower response compared with some prior reports.

The authors interpret the clinical course as consistent with a meaningful antisuicidal and antidepressant effect of low-dose ketamine in this medically ill inpatient, while acknowledging the evidence here is limited by the single-case, uncontrolled design. They argue the likelihood that improvement was treatment-related on three grounds: suicidal ideation had been persistently severe for months and through two weeks of hospitalisation until ketamine was given; a placebo effect would be more likely to appear immediately after the first infusion rather than after a second; and venlafaxine had been prescribed only one day before the first infusion, an interval too short to account for the observed improvement. In discussing the practicality of ketamine in a general hospital, the authors note that low-dose ketamine is already used for refractory pain and has an acceptable short-term safety profile when vital-sign monitoring and anaesthetic support are available. They contrast this with electroconvulsive therapy, which was unavailable at their hospital and would have entailed transport risks and delays in initiation related to medical instability and pretreatment requirements. The report also highlights potential acceptability advantages of ketamine compared with electroconvulsive therapy given public stigma. The authors situate their findings among earlier studies reporting rapid decreases in depressive symptoms and hopelessness after ketamine, and suggest that the patient’s low BMI may explain the relatively slower onset after the first infusion given prior correlations between body mass index and early antidepressant response. Key limitations acknowledged by the authors include the lack of a control condition, single-patient design and inability to draw causal conclusions. They also recognise that sustained improvement may have been influenced by subsequent specialised psychiatric care and the introduction of mirtazapine after the ketamine infusions. The authors conclude that, on balance, current safety data and this clinical example indicate a favourable benefit–risk ratio for ketamine to treat severe suicidal ideation in general hospital inpatients when multidisciplinary monitoring is feasible, but they call for further studies in consultation–liaison psychiatry to confirm this appraisal.

Given the reported tolerability and the need for rapid reduction of suicidal intent in settings where environmental safety cannot be assured, the authors conclude that low-dose ketamine may offer an excellent benefit–risk profile for inpatients in general hospitals. They recommend additional research in consultation–liaison settings to substantiate this conclusion but note that available safety data suggest nonresponse rather than serious adverse events is the principal hazard when ketamine is used under appropriate monitoring and multidisciplinary collaboration.