Behavioural Activation Therapy and Ketamine for Treatment-Resistant Depression

This phase III study is a single-site, prospective, parallel-arm, randomized proof-of-concept clinical trial designed to estimate the preliminary effects of augmenting repeated IV ketamine treatment with concurrent BA therapy, in individuals experiencing moderate to severe treatment resistant depressive episode.

The overall goal of this work is to maximize and sustain the beneficial effects of ketamine through combined treatment with BA therapy. The central hypothesis is that patients treated concurrently with ketamine and BA will demonstrate preliminary evidence of benefit, reflected by greater improvement in depressive symptoms and participant-reported functional outcomes compared to those treated with ketamine alone.

Participants will be randomized to one of two groups: Arm 1) concurrent ketamine and BA therapy started from treatment initiation, or Arm 2) ketamine treatment alone. Both arms will undergo IV ketamine infusions administered twice weekly for three weeks (Induction Phase). Participants in Arm 1 will also undergo BA therapy sessions twice weekly for three weeks during the Induction Phase. Responders to Induction Phase treatment (defined as ≥50% reduction in MADRS total scores from Baseline to end of Induction Phase) will proceed to undergo an additional 12 weeks of ketamine infusions in the Maintenance and Discharge Preparation Phases (weekly for 8 weeks, then every other week for 4 weeks, respectively). Nonresponders to the Induction Phase (\<50% reduction in MADRS total scores) will cease receiving ketamine infusions. Those in Arm 2 (ketamine alone) will complete their study participation at this point. Those in Arm 1 (BA+ketamine) will proceed to undergo an additional 12 weeks of BA therapy in the Maintenance and Discharge Preparation Phases (weekly for 8 weeks, then every other week for 4 weeks).

Participants receive IV ketamine infusions and concurrent BA therapy, both administered twice weekly for three weeks (Induction Phase). Responders to Induction Phase treatment will proceed to undergo an additional 12 weeks of ketamine infusions and BA therapy in the Maintenance and Discharge Preparation Phases (weekly for 8 weeks, then every other week for 4 weeks, respectively). Nonresponders to the Induction Phase will cease receiving ketamine infusions and will undergo an additional 12 weeks of BA therapy in the Maintenance and Discharge Preparation Phases (weekly for 8 weeks, then every other week for 4 weeks).

Drug: Ketamine (0.5 mg/kg) · Behavioral: Behavioural Activation Therapy

Participants will undergo IV ketamine infusions administered twice weekly for three weeks (Induction Phase). Responders to Induction Phase treatment will proceed to undergo an additional 12 weeks of ketamine infusions in the Maintenance and Discharge Preparation Phases (weekly for 8 weeks, then every other week for 4 weeks, respectively). Nonresponders to the Induction Phase will complete their study participation at this point.

Drug: Ketamine (0.5 mg/kg)

IV ketamine will be administered under medical supervision at a fixed dose of 0.5 mg/kg infused over 40 minutes. Treatments will be administered twice weekly for three weeks during the Induction Phase (6 treatments). Participants' response to ketamine will be assessed after the Induction Phase. Those who do not meet response criteria (\<50% reduction in MADRS score) will be deemed Nonresponders and will conclude receiving ketamine at that time. Those who meet the response criteria (≥50% reduction in MADRS score) will be deemed Responders and will proceed to the Maintenance Phase. During the Maintenance Phase, ketamine treatments will be administered once weekly for 8 weeks (8 treatments), followed by once biweekly for four weeks during the Discharge Preparation Phase (2 treatments). Responders will receive a total of 16 ketamine infusions over 15 weeks.

BA therapy is a structured, primarily talk therapy that focuses on helping people with depression increase engagement in positive, meaningful activities and reduce avoidance behaviors that reinforce low mood. The BA therapy protocol will be based on the approach described by Martell et al. (2022). Therapy sessions will be delivered virtually or in person according to participant preference. Participants in Arm 1 will receive a total of 16 BA sessions at a frequency of twice weekly for 3 weeks during the Induction Phase (6 sessions), once weekly for 8 weeks during the Maintenance Phase (8 sessions), and once biweekly for 4 weeks during the Discharge Preparation Phase (2 sessions). BA therapy sessions can occur on the same day as ketamine infusions, but not during or after the infusion.

Time frame: Week 0 to end of Week 3 and end of Week 15

Estimated between-group difference in change in MADRS total score from baseline (Pre-Treatment/Week 0) to the end of the Induction Phase (Post-Induction/Week 3). Additional efficacy assessment time point will include end of study (Post-Treatment/Week 15).

Time frame: Week 0 to end of Week 3 and end of Week 15

Estimated between-group differences in clinically meaningful antidepressant outcomes, including response rate (≥50% decrease in MADRS score) and remission rate (MADRS score ≤10), assessed from baseline (Pre-Treatment/Week 0) to end of Induction Phase (Post-Induction/Week 3), with additional assessment time point at the end of study (Post-Treatment/Week 15).

Time frame: Week 0 to end of Week 3 and end of Week 15

Estimated between-group differences in changes in participant-reported functional outcomes, including self-reported depression, anxiety, quality of life, anhedonia, physical activity, and functional disability, assessed from baseline (Pre-Treatment/Week 0) to end of Induction Phase (Post-Induction/Week 3), with additional assessment time point at the end of study (Post-Treatment/Week 15).

Optimizing the Synergy Between Behavioural Activation Therapy and Intravenous Ketamine for Treatment-Resistant Depression