Could skipping a day of antipsychotics reduce side effects without worsening symptoms?
NCT ID NCT04478838
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study looks at whether taking antipsychotic medication every other day is as effective as taking it daily for people with schizophrenia. 120 participants will be randomly assigned to either daily dosing or every-other-day dosing for one year. The goal is to see if extended dosing can reduce side effects while keeping symptoms under control.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
-
About 120 people
The number the study aims to enrol. It can still change while the study runs.
- Started
-
Jun 2022
- Expected to finish
-
Sep 2028
An estimate. End dates often move.
- Lead sponsor
-
Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
18 years and older
- Sex
-
Anyone
- Healthy volunteers
-
Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: (i) A primary diagnosis of a Schizophrenia Spectrum or Other Psychotic Disorder as defined by the DSM-5 diagnosis and confirmed by the MINI (Version 7.0.2) (ii) age 18 or older (iii) female participants of childbearing potential must be using a reliable method of contraception and have a negative pregnancy test at the time of enrolment and must, in the investigator's opinion, practice a clinically accepted, reliable method of contraception during this study. Male participants must not father a baby during their time in the study (iv) ability to communicate in English (v) capacity to provide written, informed consent, as assessed using the MacCAT-CR at time of consent (vi) stabilized as outpatients with a single oral AP (risperidone or olanzapine or paliperidone\*) at the same dose for ≥3 months i. On a prescribed risperidone dose of between 1-6mg, or a prescribed olanzapine dose of between 5-20mg, or a prescribed paliperidone 3-12mg (vii) evidence of adherence with current AP treatment Exclusion Criteria: (i) exposure to a depot AP within 1 year (i.e., no depot AP injection within the last year) (ii) Current diagnosis of substance use disorder according to DSM-5 criteria (verified through the MINI for Psychotic Disorders (Version 7.0.2) and a positive drug screen for street and /or prescription drugs not prescribed to the participant by treating physicians (iii) ECT within the last 3 months (iv) pregnancy or lactation (v) neurological condition (dementia including Alzheimer's disease, multiple sclerosis, epilepsy, stroke, or traumatic brain injury) (vi) allergy to the study drugs and their excipients (vii) allergy (e.g., galactosaemia) or severe intolerance to lactose (viii) negative urine drug screen result for Olanzapine or Risperidone or Paliperidone (if applicable)
Get updates
Get notified about this study
Sign up to get updates when this study changes or when new studies for Antipsychotic agents are added.
Genom att skicka in godkänner du våra Användarvillkor
Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
-
The places running it
1 site. The list below names each one and where it is.
-
The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
-
A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
-
Centre for Addiction and Mental Health
RECRUITINGToronto, Ontario, M5T 1R8, Canada
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Scientists probe brain's reward system in mental illness
- New schizophrenia drug targets brain glutamate, not dopamine
- New drug candidate takes aim at schizophrenia symptoms
- New schizophrenia drug goes Head-to-Head with standard antipsychotics in Long-Term trial
- Five-Year safety check for experimental schizophrenia drug
- A shot every few weeks? new drug tested for schizophrenia