Anxiolytic effects of acute and maintenance ketamine, as assessed by the Fear Questionnaire subscales and the Spielberger State Anxiety Rating Scale.

Abstract

Ketamine has rapid anxiolytic effects in treatment-resistant obsessive compulsive, post-traumatic stress, generalised anxiety and social anxiety disorders. This study aimed to assess changes following acute and maintenance ketamine therapy on the Fear Questionnaire (FQ) subscales and the Spielberger State Anxiety Inventory (SSAI). This secondary analysis used data from a mixed open-label and double-blinded placebo-controlled study. A total of 24 patients received short-term ascending subcutaneous doses of ketamine and were then eligible to enter a 3-month maintenance phase of 1 mg/kg ketamine dosed once or twice weekly. FQ and SSAI data were analysed using mixed models to identify between-dose differences and to describe trends during maintenance. Acute ketamine dosing showed a rapid dose-related reduction in all three FQ subscales (agoraphobia, social phobia and blood-injury phobia) and in the SSAI. A progressive decrease in pre-dose rating-scale scores was evident during the 3 months of maintenance therapy. Ketamine demonstrated dose-related improvements in all FQ subscales and in the SSAI. Both scales appear to be suitable tools to assess the anxiolytic effects of ketamine in patients with treatment-resistant anxiety. Furthermore, ketamine appears to have broad, dose-related anti-phobic effects. These findings raise the possibility that ketamine may have therapeutic potential in the treatment of other phobic states, such as specific phobia.