RecruitingNAINTERVENTIONAL

Does Abnormal Insulin Action in the Brain Underlie Cognitive and Metabolic Dysfunction in Schizophrenia

This study aims to understand if an issue with how the brain uses insulin might be linked to common thinking and memory problems, along with health challenges like obesity and diabetes, often seen in people with schizophrenia. We know that conditions like diabetes can make thinking problems worse for individuals with schizophrenia. Insulin plays a key role in brain functions, and researchers believe that problems with it could be a common thread connecting these issues. To find out, participants will receive insulin through a nasal spray, or a dummy spray (placebo), before having a special brain scan. This scan helps scientists see how the brain uses sugar. By comparing results between people with schizophrenia and healthy individuals, they hope to learn more about new ways to help those affected.

At a glance

Status

Recruiting

Phase

Sponsor

Centre for Addiction and Mental Health

Enrolment target

Start

01 Apr 2023

Estimated completion

01 Aug 2026

Schizophrenia Healthy

What is this study about?

This study is designed to explore a new idea about schizophrenia. Many people with schizophrenia experience difficulties with their thinking, memory, and concentration. These issues can make daily life quite challenging. On top of this, people with schizophrenia often face higher risks of other health problems, such as obesity and type 2 diabetes, and generally have a shorter life expectancy. These health problems can, in turn, make thinking and memory issues even worse.

Traditionally, schizophrenia has been seen mainly as a mental health condition. However, new research suggests it might also involve how the body and brain handle sugar and energy – almost like a 'metabolic' disorder. This study focuses on a hormone called insulin, which is crucial for managing sugar in the body. We now know that insulin also plays a very important role in brain function, affecting things like thinking and memory. The researchers wonder if problems with how the brain uses insulin could be a root cause that explains both the thinking difficulties and the metabolic health problems seen in schizophrenia.

To investigate this, the study will compare people with schizophrenia to healthy volunteers. All participants will either be given a special insulin nasal spray or a 'placebo' spray (which looks and feels like the insulin spray but contains no active medicine). Afterwards, they will have a special type of brain scan called a PET scan. This scan helps doctors see how the brain uses sugar, giving them clues about how well insulin is working in different brain areas. By looking at these differences, the study hopes to shed light on whether brain insulin problems are indeed a key link in schizophrenia, potentially opening doors for new treatments in the future.

Key takeaways

Schizophrenia can affect thinking, memory, and overall health, including risks of obesity and diabetes.
This study explores if insulin problems in the brain link these cognitive and metabolic challenges.
Participants will receive either an insulin nasal spray or a placebo.
Brain scans will be used to see how the brain uses sugar after the spray.
The research aims to find new ways to understand and potentially treat schizophrenia.
Participation is voluntary, and you can withdraw at any time.

Who may be eligible?

To join this study, you usually need to be between 17 and 45 years old. This study is looking for two groups of people: those who have been diagnosed with a schizophrenia-related condition (like schizophrenia, schizoaffective disorder, or schizoaffective disorder, schizophreniform disorder, delusional disorder, brief psychotic disorder, psychotic disorder NOS, major depressive disorder with psychotic symptoms, bipolar I disorder, and bipolar II disorder, OR substance-induced psychosis, and antipsychotic treatment for schizophrenia, schizoaffective disorder, or other specified schizophrenia spectrum, other psychotic disorder, major depressive disorder with psychotic symptoms, bipolar I disorder, and bipolar II) and healthy volunteers who don't have these conditions and are otherwise well.

There are also some reasons why you might not be able to join. For example, if you have diabetes or pre-diabetes, or if you're taking medicines for weight, cholesterol, diabetes, or blood pressure, you likely won't be able to take part. Other reasons include being pregnant or breastfeeding, having certain medical conditions like liver or kidney disease, or having metal implants in your body that would make an MRI scan unsafe. You also shouldn't have a history of serious head injury or severe claustrophobia that would prevent you from having scans.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 17 and 45 years old?
Do you have a diagnosis of schizophrenia or a related condition, or are you a healthy volunteer?
Do you *not* have diabetes or pre-diabetes?
Are you *not* taking medicines for weight, cholesterol, diabetes, or blood pressure?
Are you *not* pregnant or breastfeeding?
Do you *not* have any metal implants that would prevent an MRI scan?

Answer every question to see your result.

What does participation involve?

Taking part in this study would involve several visits. You would first have some health checks to make sure you're suitable. If you qualify, you would be given either a special insulin nasal spray or a placebo spray (a dummy spray with no medicine). After that, you would have a special brain scan called a PET scan, which helps doctors see how your brain uses sugar. You might also have an MRI scan, which takes detailed pictures of your brain. The researchers will be looking at how your brain reacts to the insulin or placebo. All in all, the study involves assessments like blood tests to check your sugar levels, and possibly some questionnaires about your thinking and memory. The total time you'd be involved in the study would depend on the number of visits and tests required.

Potential risks and benefits

Participating in research always comes with potential benefits and risks. A potential benefit of this particular study is that it could help researchers better understand schizophrenia, possibly leading to new and more effective treatments in the future. As for risks, giving insulin through a nasal spray is generally safe, but there's a small chance of common side effects like a runny nose or temporary discomfort. The brain scans (PET and MRI) also have a few considerations; PET scans involve a small amount of radiation, similar to other medical scans, and MRI scans use strong magnets but no radiation, though some people find them noisy or feel claustrophobic. You would also have blood tests, which might cause minor bruising. Remember, your participation is completely voluntary, and you have the right to withdraw from the study at any time without giving a reason, and it won't affect your medical care.

Locations (1)

Centre for Addiction and Mental Health
Verified postcode
Toronto, Canada· Recruiting

Common questions

What is the main goal of this study?

The main goal is to see if problems with how the brain uses insulin are connected to thinking difficulties and other health issues in people with schizophrenia.

What is 'intranasal insulin'?

It's a way of giving insulin through a nasal spray directly into the nose, hoping it reaches the brain more effectively.

What is a 'placebo'?

A placebo is a dummy treatment that looks and feels like the real thing but doesn't contain any active medicine. It helps researchers compare the effects of the treatment.

Will I know if I'm getting insulin or the placebo?

No, it's a 'blinded' study, meaning neither you nor the research team will know who is getting the insulin or the placebo until after the study is over. This ensures fair results.

What are the brain scans for?

The scans (PET and MRI) help researchers look at how your brain uses sugar and to get detailed pictures of your brain, which can give clues about how well insulin is working there.

How to find out more

Mahavir Agarwal, MD, PhD

mahavir.agarwal@camh.ca 416-535-8501 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.