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How insulin in the brain affects thinking and metabolism in schizophrenia

Plain-English translation of NCT05748990 on ClinicalTrials.gov ↗ · Source last updated May 2026 · Translation generated June 2026 · How we translate trials

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This study doesn't follow the usual testing phases — it may be an observational study or a different type of research.

What is this trial?

Researchers are investigating whether a problem with how the brain uses insulin might explain why people with schizophrenia often experience both difficulty with thinking and memory and metabolic problems like weight gain and diabetes. In this study, participants will receive (a medication delivered through the nose) and then undergo brain imaging scans to see how their brains respond. The goal is to understand if treating insulin resistance in the brain could help address both the cognitive and metabolic challenges that people with schizophrenia face.

People with schizophrenia often struggle with two major problems at the same time: difficulty thinking clearly and remembering things, and metabolic issues like obesity and diabetes. Currently, available treatments help reduce hallucinations and delusions but do not improve thinking problems, and do not address the metabolic complications. This research is exploring whether abnormal brain insulin action might be the common underlying cause of both problems, opening the door to new treatments that could help with both issues.

Do you qualify?

You likely qualify if…

you are between 17 and 45 years old
you have been diagnosed with schizophrenia spectrum disorder or another qualifying psychotic condition and are receiving antipsychotic treatment
you have a healthy body mass index (BMI of 27 or lower)
you are willing to receive intranasal insulin and undergo brain imaging scans (PET and MRI)
for healthy controls: you have no significant mental health diagnoses and are matched to a participant with schizophrenia on age, sex, handedness, and body size

You likely don't qualify if…

you have moderate to severe substance use disorder
you have diabetes, prediabetes, or impaired glucose tolerance
you are at acute risk for suicide
you are currently taking diabetes medications, blood pressure medications, weight loss medications, or lipid-lowering medications
you have metal implants (such as pacemakers, metallic heart valves, or surgical clips) or other conditions that would prevent you from safely undergoing MRI or PET scans
you weigh more than 350 pounds or have claustrophobia that would make it difficult to be in an MRI scanner

What participation looks like

If you enroll, you will visit the research center where you will receive (or placebo) through your nose, and then undergo brain imaging scans—specifically a PET scan and an MRI scan—to measure how your brain responds to the medication. The study will also involve screening tests to confirm your eligibility, such as an oral glucose tolerance test, and review of your medical history. Your participation will help researchers understand whether brain insulin action might be a key target for new treatments that address both thinking problems and metabolic issues in schizophrenia.

AI-generated summary from trial data · Jun 23, 2026 · Not medical advice

How insulin in the brain affects thinking and metabolism in schizophrenia

What is this trial?

Do you qualify?

What participation looks like

Trial locations(1 site)