NCT07252752

Dopamine and Insulin in Psychosis

Dopamine and Insulin in Psychosis: Imaging the Effects of Intranasal Insulin on Dopamine Transmission

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 46 (estimated)
• Sponsor: Medical University of Vienna · Academic / Other
• Sex: All
• Age: 18 Years – 40 Years
• Healthy volunteers: Accepted

Summary

Patients with schizophrenia have a high risk of developing metabolic disorders and current evidence points to an overlap in mechanisms underlying psychiatric symptoms and metabolic disturbances. The main goal of this study is to investigate effects of brain insulin on dopamine signaling and energy metabolism in patients with schizophrenia experiencing their first psychotic episode (FEP). To this end, patients with schizophrenia and healthy volunteers will undergo two \[11C\]-(+)-PHNO positron emission (PET) scans to measure the changes in dopamine receptor availability after nasally applied insulin, as well as single proton magnetic resonance spectroscopy (1H-MRS) to assess the impact of intranasal insulin on levels of glucose and glutamate in the hippocampus.

Conditions

• First Episode Psychosis (FEP)

Interventions

Type	Name	Description
DRUG	Intranasal Insulin	160 IU intranasal insulin is administered using precision air pumps twice: 15 min prior to the PET scan and 35 min prior to the 1H-MRS scan
DRUG	Placebo	Insulin-free dilution buffer is administered using precision air pumps 15 min prior to the PET scan
DRUG	Low dose insulin infusion	2.5 mU/kg insulin in 100 ml isotonic saline is infused intravenously over 15min prior to PET scan when placebo is administered intranasally
DRUG	Placebo infusion	100 ml saline is infused intravenously over 15min prior to PET scan when insulin is administered intranasally
RADIATION	[11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)	Each participant undergoes a 90-min \[11C\]-(+)-PHNO scan twice

Timeline

• Start date: 2026-01-01
• Primary completion: 2029-01-01
• Completion: 2029-01-01
• First posted: 2025-11-28
• Last updated: 2025-11-28

Locations

1 site across 1 country: Austria