Insomnia and anxiety exhibit distinct short-term associations following ketamine in treatment-resistant depression

Insomnia and anxiety frequently co-occur with treatment-resistant depression (TRD). This study examined short-term changes in depression, anxiety, and insomnia symptoms post-ketamine in TRD and their inter-relationships. Seventy-one patients with TRD were assessed at baseline and 24 h after intravenous ketamine (0.5 mg/kg).

Depression, anxiety, and insomnia were measured using the Montgomery–Åsberg Depression Rating Scale (MADRS), the Hamilton Anxiety Rating Scale (HAM-A), and insomnia items from the Hamilton Depression Rating Scale (HAM-D), respectively. Linear mixed-effects models tested pre–post changes, while Spearman, Pearson, and simple linear regression examined associations between symptom domains. As an exploratory analysis, linear discriminant analysis (LDA) and logistic regression were used to classify insomnia improvement.

All symptom domains decreased significantly post-ketamine treatment, including depression (MADRS; β = –11.72, P