What is this study studying for schizophrenia?

This study is evaluating whether taking antipsychotic medication every other day works as well as daily dosing for people with schizophrenia. It also looks at whether reduced dosing might lead to fewer side effects. The research is sponsored by the Centre for Addiction and Mental Health and aims to improve treatment options.

Who may be eligible for this schizophrenia clinical trial?

Adults aged 18 or older with a confirmed diagnosis of schizophrenia spectrum or other psychotic disorder may be eligible. Participants must be stabilized on a single oral antipsychotic medication like risperidone, olanzapine, or paliperidone at a stable dose for at least three months. Both males and females can join, but females must use reliable contraception. Please review eligibility criteria for more details.

Is there any cost to participate in this schizophrenia clinical trial?

Study-related care, including the study drug or procedure and all trial visits, is provided at no cost. However, personal travel expenses and other costs may vary and are not guaranteed to be covered. Participants can plan accordingly based on their situation.

Actively Recruiting

Phase 4

Age: 18Years +

All Genders

ID04478838

Comparing Daily and Alternate Day Dosing of Antipsychotic Medications for Schizophrenia Treatment A One-Year Randomized, Double-Blind Study

Led by Centre for Addiction and Mental Health · Updated on 2026-04-13

120

Participants Needed

Research Sites

52 weeks

Total Duration

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

Age: 18Years +

All Genders

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

Research Team

Carol Borlido

Gary Remington, MD, PhD

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