A machine-learning model using structural brain scans predicted which adults with treatment-resistant depression would respond to a single ketamine infusion. The model, trained on 99 participants, achieved 72% balanced accuracy in the discovery sample and 60% in two independent groups, with performance dropping to chance in a saline-treated control group. Greater gray matter volume in frontal regions predicted response, while greater cerebellar volume predicted non-response. The findings suggest that pre-treatment brain structure may help guide personalized treatment decisions for ketamine therapy.
A 28-year-old woman receiving ketamine for depression developed ulcerative cystitis, a complication previously seen only in recreational users. Ketamine-induced cystitis (KIC) causes lower urinary tract symptoms—dysuria, urgency, nocturia, frequency—and can progress to incontinence, hematuria, bladder fibrosis, and kidney damage. The exact cause is unknown, but theories include direct toxicity from ketamine metabolites, an IgE-mediated allergic response, and other inflammatory pathways. Early diagnosis and stopping ketamine can reverse symptoms and prevent further harm. This is the first reported case of KIC from therapeutic-dose ketamine for depression.