Dopamine D2 and D3 Receptor Occupancy and Clinical Response in Older Patients With Schizophrenia (NCT00825045) | Clinical Trial Compass
UnknownNot Applicable
Dopamine D2 and D3 Receptor Occupancy and Clinical Response in Older Patients With Schizophrenia
Canada14 participantsStarted 2008-12
Plain-language summary
This study will provide information regarding dopamine D2/D3 occupancy related with clinical/adverse effects in older people with schizophrenia and schizoaffective disorder. The results of this study will also show an appropriate dose range in order to evade undesirable adverse effects while deriving therapeutic effects, which will directly serve to guide physicians in clinical practice. Furthermore, the findings of this study will elucidate mechanisms underlying older people's increased sensitivity to antipsychotic drugs. In addition, the contribution of D2 and D3 in mediating antipsychotic response will be contrasted, using 2 radiotracers, which has never been tested in an older population.
The hypotheses are as follows: First, clinical response (i.e., a ≥ 20% decrease in the Brief Psychiatric Rating Scale total score) will be achieved in older patients with occupancy that is lower than the threshold of 60% in historical young controls. Second, prolactin elevation and EPS will be detected in older patients with occupancies that are lower than the thresholds of 72 and 78% reported in historical young controls. Third, dopamine D2 receptor occupancy will be inversely correlated with subjective well-beings. Fourth, the binding potential and receptor occupancy will be at least 20% lower with \[11C\]-(+)-PHNO than with \[11C\]-raclopride in the caudate/putamen. Fifth, the binding of \[11C\]-(+)-PHNO in the globus pallidus will be higher than that of \[11C\]-raclopride.
Who can participate
Age range
50 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Age of 50 and older at time of scanning
* Inpatients or outpatients
* DSM-IV/SCID diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder
* Having NOT been treated with oral antipsychotic treatment for at least 2 weeks or long-acting antipsychotics for at least 6 months (Please note that patients will not be withdrawn from antipsychotic medications for the purpose of meeting inclusion criteria for this study).
Exclusion Criteria:
* Known history of intolerance or inefficacy to risperidone
* Participation in this study would result in exceeding the annual radiation dose limits (20 mSv) for human subjects participating in research studies.
* Substance abuse or dependence (within past six months)
* Positive urine drug screen
* Positive serum pregnancy test at screening or positive urine pregnancy test before PET scan
* Metal implants or a pace-maker that would preclude the MRI scan
* History of head trauma resulting in loss of consciousness \>30 minutes that required medical attention
* Unstable physical illness or significant neurological disorder including a seizure disorder
* Inappropriate size of head, neck, and body to be able to fit the PET and MRI scans
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
The occupancy of risperidone at the D2 and D3 receptor, using [11C]-raclopride and [11C]-(+)-PHNO, respectively.