First Episode Psychosis (FEP)DIPSNCT07252752
Dopamine and Insulin in Psychosis
A study testing Intranasal Insulin, Low dose insulin infusion and [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) in people with First Episode Psychosis (FEP), run by Medical University of Vienna at 1 site in Austria.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- First Episode Psychosis (FEP)
- What is being tested?
- Intranasal Insulin, Low dose insulin infusion and [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)
- Type of treatment
- Injection or infusion, Surgery or procedure
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 46 participants
- Where
- 1 siteAustria
- Study dates
- 1 Jan 2026to 1 Jan 2029
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- All participants
- age 18-40
- Body mass index (BMI) range 18-25
- good general health according to physical examination and medical history
- absence of relevant abnormalities in laboratory screening, electrocardiogram (ECG) or vital signs
- no regular use of drugs of abuse or alcohol based on history and urine drug screen
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- Patients only
- diagnosis of schizophrenia or schizophreniform disorder according to DSM-5
- ability to give informed consent
- minimum Positive and Negative Syndrome Scale (PANSS) score of 55 with >3 on at least two or >4 on one PANSS psychosis item
Who cannot join
- All participants
- severe or unstable medical or neurological illness or clinically significant abnormality on screening laboratory studies or ECG
- established diagnosis of type 1 or type 2 diabetes
- current substance use disorder or regular recreational drug abuse (except nicotine and caffeine)
- pregnancy or breastfeeding
- history of head trauma resulting in loss of consciousness of >1min or requiring medical attention
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- presence of MRI exclusion criteria
- if participation in this study would exceed annual radiation dose limits (30mSv)
- clinically established diagnosis of intellectual disability
- Healthy volunteers only
- Psychiatric disorder according to Mini-International Neuropsychiatric Interview (M.I.N.I.)
- Schizophrenia or bipolar disorder in first degree family members
- Patients only
- ● Previous oral antipsychotic treatment for more than 2 weeks or previous treatment with antipsychotic depot preparation
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Austria1 site
Medical University of Vienna
Vienna, 1090
Matthaeus Willeit, +43 1 40400 ext. 35470, matthaeus.willeit@meduniwien.ac.at
About this study
Official title: Dopamine and Insulin in Psychosis: Imaging the Effects of Intranasal Insulin on Dopamine Transmission
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)
- Being tested
- Intranasal Insulin, Placebo, Low dose insulin infusion, Placebo infusion, [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)
- Keywords
- positron emission tomography (PET), dopamine, schizophrenia, intranasal insulin, magnetic resonance spectroscopy (MRS)
- Medical subject headings
- Schizophrenia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intranasal InsulinDrug
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
PlaceboDrug
Insulin-free dilution buffer is administered using precision air pumps 15 min prior to the PET scan
Low dose insulin infusionDrug
2.5 mU/kg insulin in 100 ml isotonic saline is infused intravenously over 15min prior to PET scan when placebo is administered intranasally
Placebo infusionDrug
100 ml saline is infused intravenously over 15min prior to PET scan when insulin is administered intranasally
[11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)Radiation
Each participant undergoes a 90-min [11C]-(+)-PHNO scan twice
| Study group | Role | What they receive |
|---|---|---|
| Schizophrenia group | Experimental | 20 antipsychotic-naive patients with first episode psychosis will undergo (i) two [11C]-(+)-PHNO PET scans preceded by intranasal insulin or placebo administration in a randomized counterbalanced order, and (ii) 1H-MRS before and after intranasal insulin Receives: Drug: Intranasal Insulin; Drug: Placebo; Drug: Low dose insulin infusion; Drug: Placebo infusion; Radiation: [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) |
| Healthy volunteer group | Experimental | 20 healthy volunteers will undergo (i) two [11C]-(+)-PHNO PET scans preceded by intranasal insulin or placebo administration in a randomized counterbalanced order, and (ii) 1H-MRS before and after intranasal insulin Receives: Drug: Intranasal Insulin; Drug: Placebo; Drug: Low dose insulin infusion; Drug: Placebo infusion; Radiation: [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) |
| Test-retest group | Other | 6 healthy volunteers will undergo (i) two [11C]-(+)-PHNO PET scans, and (ii) 1H-MRS for test-retest purposes Receives: Radiation: [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) |
What is being measured
The primary outcome is the main question the study is designed to answer.
[11C]-(+)-PHNO BPND values
Dopamine D2/3 receptor availability after intranasal insulin or placebo administration
Measured: Assessed on two separate study visits within 5-12 days (scan duration: 90 min)
Hippocampal glucose and glutamate concentrations
Hippocampal glucose and glutamate concentrations before and after intranasal insulin administration
Measured: Assessed during a single study visit (scan duration: 40 min in total)
Secondary outcomes (2)
Changes in blood-based parameters of energy metabolism
Changes in concentrations of selected metabolic parameters (blood glucose, insulin, c-peptide, total cholesterol, HDL, LDL, trigycerides, ketone bodies) following intranasal insulin/placebo administration, assessed by venous blood sampling
Measured: Assessed at baseline and at 15min intervals after instranasal insulin/placebo administration over a period of up to 90min
Hippocampal volumetric parameters
Whole hippocampus and hippocampal subfield volumes assessed with structural MRI
Measured: Assessed during a single study visit, at baseline (scan duration: 10min)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Nov 2025
- Study start1 Jan 2026 (estimated)
- Primary completion1 Jan 2029 (estimated)
- Study completion1 Jan 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for First Episode Psychosis (FEP)Studies of the same condition, open and under way.
- More trials run by Medical University of ViennaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 46 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medical University of Vienna
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Matthäus Willeit, Medical University of Vienna
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07252752
- Sponsor's protocol ID
- KLP4656125
- Acronym
- DIPS
- Status last verified
- Nov 2025
- First submitted
- 30 Sep 2025
- Last updated
- 28 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 28 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dopamine and Insulin in Psychosis: Imaging the Effects of Intranasal Insulin on Dopamine Transmission
- ClinicalTrials.gov ID
- NCT07252752
- Acronym / sponsor ID
- DIPS / KLP4656125
- Conditions
- First Episode Psychosis (FEP)
- Keywords
- positron emission tomography (PET), dopamine, schizophrenia, intranasal insulin, magnetic resonance spectroscopy (MRS)
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 46 participants (estimated)
- Lead sponsor
- Medical University of ViennaUniversity, hospital or other
- Study start
- 1 Jan 2026 (estimated)
- Primary completion
- 1 Jan 2029 (estimated)
- Study completion
- 1 Jan 2029 (estimated)
- First posted
- 28 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Schizophrenia group | Experimental | Drug: Intranasal Insulin, Drug: Placebo, Drug: Low dose insulin infusion, Drug: Placebo infusion, Radiation: [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)20 antipsychotic-naive patients with first episode psychosis will undergo (i) two [11C]-(+)-PHNO PET scans preceded by intranasal insulin or placebo administration in a randomized counterbalanced order, and (ii) 1H-MRS before and after intranasal insulin |
| Healthy volunteer group | Experimental | Drug: Intranasal Insulin, Drug: Placebo, Drug: Low dose insulin infusion, Drug: Placebo infusion, Radiation: [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)20 healthy volunteers will undergo (i) two [11C]-(+)-PHNO PET scans preceded by intranasal insulin or placebo administration in a randomized counterbalanced order, and (ii) 1H-MRS before and after intranasal insulin |
| Test-retest group | Other | Radiation: [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)6 healthy volunteers will undergo (i) two [11C]-(+)-PHNO PET scans, and (ii) 1H-MRS for test-retest purposes |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (10 listed)
- All participants
- age 18-40
- Body mass index (BMI) range 18-25
- good general health according to physical examination and medical history
- absence of relevant abnormalities in laboratory screening, electrocardiogram (ECG) or vital signs
Key exclusion criteria (14 listed)
- All participants
- severe or unstable medical or neurological illness or clinically significant abnormality on screening laboratory studies or ECG
- established diagnosis of type 1 or type 2 diabetes
- current substance use disorder or regular recreational drug abuse (except nicotine and caffeine)
- pregnancy or breastfeeding
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Intranasal Insulin160 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 | Healthy volunteer group, Schizophrenia group |
| PlaceboInsulin-free dilution buffer is administered using precision air pumps 15 min prior to the PET scan | Drug | Healthy volunteer group, Schizophrenia group |
| Low dose insulin infusion2.5 mU/kg insulin in 100 ml isotonic saline is infused intravenously over 15min prior to PET scan when placebo is administered intranasally | Drug | Healthy volunteer group, Schizophrenia group |
| Placebo infusion100 ml saline is infused intravenously over 15min prior to PET scan when insulin is administered intranasally | Drug | Healthy volunteer group, Schizophrenia group |
| [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO)Each participant undergoes a 90-min [11C]-(+)-PHNO scan twice | Radiation | Healthy volunteer group, Schizophrenia group, Test-retest group |
Primary outcome
[11C]-(+)-PHNO BPND values
Time frame: Assessed on two separate study visits within 5-12 days (scan duration: 90 min)
Dopamine D2/3 receptor availability after intranasal insulin or placebo administration
Hippocampal glucose and glutamate concentrations
Time frame: Assessed during a single study visit (scan duration: 40 min in total)
Hippocampal glucose and glutamate concentrations before and after intranasal insulin administration
2 secondary outcomes
Changes in blood-based parameters of energy metabolism
Time frame: Assessed at baseline and at 15min intervals after instranasal insulin/placebo administration over a period of up to 90min
Hippocampal volumetric parameters
Time frame: Assessed during a single study visit, at baseline (scan duration: 10min)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Nov 2025.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Intranasal Insulin, Low dose insulin infusion and [11C] (+)-4-propyl-(+)-4-propyl-9-hydroxynaphthoxazine (PHNO) in people with First Episode Psychosis (FEP), run by Medical University of Vienna at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 28 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Matthaeus Willeit (+43 1 40400 ext. 35470, matthaeus.willeit@meduniwien.ac.at), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
[11C]-(+)-PHNO BPND values (time frame: Assessed on two separate study visits within 5-12 days (scan duration: 90 min)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Nov 2025.