Actively Recruiting
"Extended" (Alternate Day) Antipsychotic Dosing
Led by Centre for Addiction and Mental Health · Updated on 2026-04-13
120
Participants Needed
1
Research Sites
329 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
The study wishes to examine whether "extended" antipsychotic treatment, in this case, antipsychotic treatment every other day, is as effective as daily treatment. It is also evaluating whether there may be differences in terms of side effects. Participants will be randomly assigned to either the treatment as usual group (i.e., taking antipsychotic daily) or the extended dosing group (i.e., taking antipsychotic one day on, one day off). That means, like flipping a coin, there is a 50/50 chance that participants will continue on daily dosing of your antipsychotic or have it switched to every other day dosing. This study will last for 1 year. Participants will be evaluated at the beginning and every two weeks during the first 6 months, with visits once every 4 weeks for the final 6 months. In total, participants will make 22 visits over 52 weeks to the investigator's office. The investigators hypothesize that with ED, there will be no change in symptom severity but improvement in the frequency and severity of side effects, wellbeing, and functioning.
CONDITIONS
Official Title
"Extended" (Alternate Day) Antipsychotic Dosing
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Diagnosis of a schizophrenia spectrum or other psychotic disorder confirmed by DSM-5 and MINI
- Age 18 years or older
- Female participants of childbearing potential must use reliable contraception and have a negative pregnancy test at enrollment
- Male participants must agree not to father a child during the study
- Ability to communicate in English
- Capacity to provide written informed consent as assessed by MacCAT-CR
- Stabilized as outpatients on a single oral antipsychotic (risperidone, olanzapine, or paliperidone) at the same dose for at least 3 months
- Prescribed doses: risperidone 1-6 mg, olanzapine 5-20 mg, paliperidone 3-12 mg
- Evidence of adherence to current antipsychotic treatment
You will not qualify if you...
- Received depot antipsychotic injection within the last year
- Current substance use disorder diagnosis or positive drug screen for unprescribed drugs
- Electroconvulsive therapy (ECT) within the last 3 months
- Pregnancy or breastfeeding
- Neurological conditions such as dementia, multiple sclerosis, epilepsy, stroke, or traumatic brain injury
- Allergy to study drugs or their ingredients
- Allergy or severe intolerance to lactose
- Negative urine drug screen for olanzapine, risperidone, or paliperidone if applicable
AI-Screening
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Trial Site Locations
Total: 1 location
1
Centre for Addiction and Mental Health
Toronto, Ontario, Canada, M5T 1R8
Actively Recruiting
Research Team
C
Carol Borlido
CONTACT
G
Gary Remington, MD, PhD
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
QUADRUPLE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
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