Actively Recruiting
Re-examining Maintenance Antipsychotic Treatment in Schizophrenia: Extended Antipsychotic Dosing
Led by Centre for Addiction and Mental Health · Updated on 2026-04-13
120
Participants Needed
1
Research Sites
52 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
This research aims to evaluate whether taking antipsychotic medication every other day is as effective as the usual daily dosing for people with schizophrenia or related disorders. The study also explores if the alternate day dosing reduces side effects compared to daily treatment. It is a randomized, double-blind trial designed to compare these two dosing schedules over one year. Participants will be randomly assigned to either continue their current daily antipsychotic medication (risperidone, olanzapine, or paliperidone) or switch to an alternate day dosing schedule. To maintain blinding, active medication and placebo capsules are provided in matching blister packs so participants and staff cannot tell which regimen is assigned. Doses range from 1 mg to 16 mg for risperidone, 5 mg to 20 mg for olanzapine, and 3 mg to 12 mg for paliperidone. Treatment is individualized, and other psychotropic medications can continue if stable. Participants will attend 22 visits over 52 weeks, with visits every two weeks for the first six months and monthly visits for the final six months. Researchers will assess symptom severity and side effects using several scales, including the Brief Psychiatric Rating Scale and multiple symptom and wellbeing questionnaires. The main outcome focuses on clinical deterioration at the start and end of the study. Safety and medication adherence will be closely monitored throughout the trial.
CONDITIONS
Brief Title
"Extended" (Alternate Day) Antipsychotic Dosing
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Adults aged 18 years or older
- Diagnosed with schizophrenia spectrum or other psychotic disorder confirmed by DSM-5 and MINI
- Female participants of childbearing potential must use reliable contraception and have a negative pregnancy test at enrollment
- Ability to communicate in English
- Capacity to provide written informed consent
- Stabilized as outpatients on a single oral antipsychotic (risperidone 1-6 mg, olanzapine 5-20 mg, or paliperidone 3-12 mg) at the same dose for at least 3 months
- Evidence of adherence with current antipsychotic treatment
You will not qualify if you...
- Received depot antipsychotic injection within the last year
- Current diagnosis of substance use disorder confirmed by DSM-5 and positive drug screen
- Electroconvulsive therapy 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 components
- Allergy or severe intolerance to lactose
- Negative urine drug screen for olanzapine, risperidone, or paliperidone if applicable
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - 1 year
Participants receive either alternate day dosing or daily dosing of antipsychotic medication while maintaining their current dose level. Treatment is double-blinded and individualized using matching capsules.
Biweekly visits for 6 months, then monthly visits for 6 months
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
G
Gary Remington, MD, PhD
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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