Minimizing Doses of Antipsychotic Medication in Older Patients With Schizophrenia.

• Status: Completed
• Trial end date: 2015-08-01
• Target enrollment: 0
• Participant gender: All

Summary

Since side effects of antipsychotics, dopamine D2 receptor blockers, frequently occur in older patients with schizophrenia and the risk is dose dependent, clinical guidelines universally advocate the use of lower doses. However, there is no report to test this dosing guideline with measurements of D2 receptor blockade caused by antipsychotics. In this study, dopamine D2 receptor occupancy will be measured, using Positron Emission Tomography (PET), in 40 patients aged 50 and older with schizophrenia-spectrum disorders before and after a gradual 40 % dose reduction of antipsychotics that was safely achieved in the past study while setting a target dose still above the lower limit of the dose range recommended in clinical guidelines for older patients. Our goal is to relate changes in clinical outcome, including subjective and objective clinical ratings, to dopamine D2 receptor occupancy, and compare these results with the data for younger patients in the literature.

• Phase: N/A
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Centre for Addiction and Mental Health
• Treatments: Antipsychotic Agents; Dopamine; Olanzapine; Risperidone

Criteria

Inclusion Criteria:

• Age of 50 and older

• DSM-IV/SCID diagnosis of schizophrenia, schizoaffective disorder, schizophreniform disorder, delusional disorder, or psychotic disorder NOS

• Having been treated with oral risperidone at a steady dose of ≥ 2 mg/day, or with olanzapine at a steady dose of ≥10 mg/day, for at least 12 months.

Exclusion Criteria:

• Incapacity to provide consent to psychiatric treatment

• 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

• Having taken more than one dose of antipsychotics other than risperidone or olanzapine during the 7 days preceding the PET scan

• History of treatment with long-acting (depot) neuroleptic antipsychotic medication or Risperdal Consta within 12 months of PET scanning

• Metal implants or a pace-maker that would preclude the MRI scan

• Addition of or change in dose of antidepressants, valproic acid, lithium, carbamazepine, or lamotrigine for mental health reasons within 12 months of screening

• 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

• Size of head, neck, and body being unable to fit PET and MRI scanners

• Refusal to give consent to investigator to communicate with physician of record for the entire duration of the study

• Psychiatric concerns raised by the physician of record regarding participation in the study.