Recruiting

MetforminMetformin for Antipsychotic-induced Weight Gain in Adults With Intellectual Disability

Sponsor:

Centre for Addiction and Mental Health

Code:

NCT05744479

Conditions

Intellectual Disability

Developmental Disability

Obesity

Eligibility Criteria

Sex: All

Age: 16 - 65

Healthy Volunteers: Not accepted

Interventions

Metformin

Placebo

Lifestyle Intervention

Study Details

Brief summary:

People with IDD (intellectual and developmental disability) have very high rates of obesity and die prematurely from cardiometabolic disease. While antipsychotics contribute to this problem, their use is necessary and appropriate in a significant subgroup of individuals with IDD. Exercise and diet interventions have limitations and may not be sufficient, requiring effective adjunctive pharmacological approaches to target obesity and related comorbidities in IDD. However, persons with IDD treated with antipsychotics are systematically excluded from clinical trials hindering development of evidence to help guide safe and effective treatment of these comorbidities. Moreover, evidence from other disorders cannot be extrapolated to IDD given inherent biological differences between disorders. This trial will address the identified gaps, which extend beyond cardiovascular morbidity and negatively impact psychosocial outcomes, in a hugely underserviced population.This is the the first RCT (randomized control trial) to examine the efficacy of metformin in overweight or obese adults with IDD who have experienced antipsychotic-induced weight gain. By generating efficacy data for a very accessible and scalable intervention, allows for guideline and implementation strategies to address a recalcitrant health problem.

Conditions

Intellectual Disability

Developmental Disability

Obesity

Study ID

NCT05744479

Start date

Feb 28, 2023

Status verified date

Mar, 2026

Completion date

Mar 1, 2027

Anticipated

Primary completion date

Mar 1, 2027

Anticipated

Eligibility Criteria

Sex: All

Age: 16 - 65

Healthy Volunteers: Not accepted

Inclusion Criteria:

Stable outpatients
Age 16-65 years
Diagnosed with an IDD
On maintenance treatment with an antipsychotic (stable dose for ≥3 months).
BMI must be ≥30 kg/m2, OR ≥27 kg/m2 with at least one weight-related comorbidity (treated or untreated) such as: hypertension, dyslipidaemia, obstructive sleep apnea, or impaired fasting glucose, OR >=25 for individuals who have gained > 5% body weight in association with AP use.
Females of child-bearing age must be on one of the following regular contraceptives:

1. Agree to abstain from sex for the duration of the trial or
2. A barrier method of a diaphragm with spermicide and/or Latex condom or
3. An oral contraceptive agent, implantable contraceptive or an injectable contraceptive for at least six months prior to entering the study and will continue its use throughout the study, or
4. An intrauterine device, or
5. Partner has had a vasectomy at least 3 months prior to study start

Exclusion Criteria:

Females who are nursing, currently pregnant, or have a positive pregnancy test
Clinical or laboratory evidence of uncompensated cardiovascular, endocrine, haematological, hepatic, renal, or pulmonary disease
Previous treatment and lack of efficacy or tolerability with metformin
History or diagnosis of Type 1 Diabetes (T1D) or Type 2 Diabetes (TD2) or fasting blood work, HbA1c > 6.5%
History of metabolic acidosis or lactic acidosis
Treatment with weight-lowering agents
Medications with significant renal impact
Major medical or surgical event in the preceding 3 months
Acute suicidal risk.
Moderate to severe substance use disorder, other than caffein or nicotine use disorder

Study Design

Enrollment

100 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Metformin (Oral)

50 participants will be administered oral metformin titrated to a maximum dose of 2000mg/day for 24 weeks.

placebo comparator: Placebo

50 participants will be administered an identical oral placebo for 24 weeks.

Interventions

Metformin

Metformin oral, 2000mg/day, for 24 weeks.

Placebo

Oral placebo for 24 weeks

Lifestyle Intervention

Participants from both groups will meet a dietician and a diabetes educator at the study start to obtain advice regarding healthy diet, portion size, and meal planning to improve physical health. All participants will be invited to monthly group meetings to learn skills which will help them in a variety of wellness areas such as physical exercises and diet. Attendance in these sessions will be encouraged but not mandatory, and attendance will be recorded. Fidelity with these interventions will be captured using diet and physical activity questionnaires at RCT start, midpoint and end, and end of open label phase.

Primary outcome measure

Individual's percentage change in body weight [ Time Frame: Weeks 0, 4, 8, 12, 16, 10, 24 ]

Central Contacts and Locations

Central contacts

Mahavir Agarwal, MD, PhD

4165358501 mahavir.agarwal@camh.ca

Maria Papoulias

4165358501 maria.papoulias@camh.ca

Locations

Centre for Addiction and Mental Health

Recruiting

Toronto, Ontario, Canada, M6J1H3

Contacts

Maria Papoulias, MSc

416-535-8501 maria.papoulias@camh.ca

Principal Investigator:

Mahavir Agarwal, PhD, MBBS, MD

More Information

Sponsor

Centre for Addiction and Mental Health

Last update posted

Mar 31, 2026

Last verified

Mar, 2026

Keywords

Intellectual Disability
Developmental Disability
Obesity
Metformin

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Centre for Addiction and Mental Health on 2026-03-31.