Conditions: Schizophrenia Schizoaffective Disorder Schizophreniform Disorder
Keywords: Schizophrenia Positive symptoms Negative symptoms Cognitive deficits
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 29
Healthy volunteers: no

Brief summary:
This is a 6-week, randomized, double blind, parallel groups designed, olanzapine-controlled trial of oral dipyridamole in symptomatic patients with a (DSM IV) diagnosis of schizophrenia, schizoaffective or schizophreniform disorder. This pilot study aims to provide preliminary estimates of whether the effect sizes of dipyridamole on positive symptoms, negative symptoms, and cognitive deficits differ between schizophrenia patients treated with dipyridamole, and schizophrenia patients treated with olanzapine. A total of 30 subjects will be recruited locally.

Detailed description:
Since the demonstrated success of chlorpromazine in treating psychosis in the1950's, the pharmacotherapy of schizophrenia has focused mainly on drugs with antidopaminergic actions. These drugs have robust effects on reality distortion and disorganization symptom complexes, but minimal effect on cognitive impairment, negative symptoms, and functional outcome and quality of life measures. Newer generation antipsychotic drugs have a similar profile of effects, with some advantages on the course of depression, hostility, suicide, hospital readmission rates and motor side effect measures. Side effects such as weight gain, increase in cardiovascular stress and diabetes risk are associated with some new generation drugs. A new class of drugs is needed to address the inadequate effectiveness and the side-effect disadvantages of the currently available pharmacological agents for the treatment of schizophrenia. Recently, new treatment strategies using nicotinergic drugs or agonists at the glycine modulatory site of the glutamatergic N-methyl-D-aspartate (NMDA) receptor have been employed in clinical trials with mixed results. Our proposal focuses on a clinically available adenosine agonist, dipyridamole, in a 6-week clinical trial. Published data suggest effectiveness of dipyridamole in treating psychosis when added to haloperidol treatment. The effectiveness of dipyridamole alone in treating schizophrenia symptoms, although indirectly suggested by several lines of evidence, has not been tested.

Arms:
arm 1: Dipyridamole arm 2: Olanzapine

Interventions: intervention 1: Dipyridamole intervention 2: Olanzapine
Intervention descriptions: intervention 1: Week 1- 50 mg bid Week 2- 50 mg am and 100 mg pm Weeks 3-6 100 mg am and 100 mg pm intervention 2: Week 1- 5 mg BID Week 2- 5 mg am and 10 mg pm Weeks 3-6 10 mg am and 10 mg pm

Protocol document: