The high prevalence of cannabis and other substance use disorders are a major barrier to recovery in people with schizophrenia. Moreover, schizophrenia patients have significant deficits in cognitive function, which may be exacerbated by cannabis use. Complicating these problems is the lack of evidence-based treatments for co-morbid cannabis use disorders (CUDs) in schizophrenia; there are no established pharmacotherapies. Therefore, this study is investigating the effects of high-frequency (20Hz) repetitive transcranial magnetic stimulation (rTMS) on cannabis use disorder and cognitive function in patients with co-morbid schizophrenia/schizoaffective disorder. The proposed study would be the first randomized, double-blind, sham controlled trial of rTMS in patients with schizophrenia and co-morbid CUD. A total of N=40 schizophrenia smokers with co-morbid cannabis use disorder will be assigned to either active rTMS (N=20) or sham rTMS (N=20) as a treatment regimen of 5X/week treatment for four consecutive weeks. All participants will receive weekly behavioral therapy for 4 weeks. The investigators predict that active rTMS will be well-tolerated and superior to sham rTMS for the treatment of CUD in schizophrenia.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
24
On Day 1, the resting motor threshold (RMT) will be determined according to previous published methods \[Cardenas-Morales et al. 2013\] and the rTMS will be delivered at an intensity of 90% of the participant's RMT. rTMS will be administered at 20 Hz (25 trains, 30 pulses per train, 30 second intertrain interval).
On Day 1, the resting motor threshold (RMT) will be determined according to previous published methods \[Cardenas-Morales et al. 2013\] and the Sham rTMS will be delivered at an intensity of 90% of the participant's RMT. rTMS will be administered at 20 Hz with the B65 placebo coil (25 trains, 30 pulses per train, 30 second intertrain interval).
In order to support participants in their abstinence plan, individual weekly sessions of supportive counselling will be administered over the course of the study on 1 time per week over 4 weeks (28 days of abstinence).
Centre for Addiction and Mental Health
Toronto, Ontario, Canada
The effects of active versus sham rTMS directed to DLPFC on cannabis abstinence in cannabis-dependent patients with schizophrenia as assessed by urine screens for changes in Tetrahydrocannabinol (THC) content.
Urine samples will be collected weekly during the abstinence period and tested by study personnel using the Semi-Quantitative THC Pre-Dosage Test (NarcoCheck®, Villejuif, France).
Time frame: Weekly (Day 0, Day 7, Day 14, Day 21, Day 28) and at 8 weeks (Follow-up Day 56)
The effects of active versus sham rTMS directed to DLPFC on cannabis abstinence in cannabis-dependent patients with schizophrenia as assessed by urine screens for changes in Tetrahydrocannabinol (THC) content.
Urine samples at Day 28 and Follow-Up (Day 56) will be sent to CAMH's clinical laboratory for gas chromatography/mass spectrometry (GC/MS) analysis to obtain quantitative THC-COOH and creatinine concentrations. Thus abstinence will also be assessed with combined quantitative urinalysis (\<50 ng/ml) and TLFB assessment.
Time frame: Up to 4 weeks (Day 28) and 8 weeks (Follow-Up Day 56)
The effects of active (20 Hz) versus sham rTMS on change in cognitive function in cannabis dependent patients with schizophrenia as assessed by a cognitive battery administered at Baseline and at Day 28.
The cognitive battery (Day 28) will include the primary outcome of verbal memory (assessed by HVLT) and will be compared to baseline (Day 1) performance. Cortical inhibition will also be assessed and compared between Day 1 and Day 28 performance.
Time frame: Up to 4 weeks (Day 28) and 8 weeks (Follow-Up Day 56)
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