Conditions: Schizophrenia
Keywords: Stable schizophrenia cognitive functioning
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 75
Healthy volunteers: no

Brief summary:
This will be a phase IV 20 -32 day prospective, double blind, double-dummy, randomised crossover study that will evaluate the effect of quetiapine XR and quetiapine IR on cognitive performance in patients with schizophrenia stabilized on a single antipsychotic medication.

Detailed description:

Arms:
arm 1: Patients randomised to Seroquel XR will have treatment for 10-16 days and after that cross-over to treatment with Seroquel IR for 10-16 days arm 2: Patients randomised to Seroquel IR will have treatment for 10-16 days and after that cross-over to treatment with Seroquel XR for 10-16 days

Interventions: intervention 1: Seroquel XR- quetiapine fumarate extended release intervention 2: Seroquel IR - quetiapine fumarate intervention 3: Placebo matching Seroquel XR intervention 4: Placebo matching Seroquel IR
Intervention descriptions: intervention 1: Seroquel XR dose 400-700 mg (in tablet form). The investigator established the dosing schedule for each patient depending on the patient's dose when entering the study. The patients continued on the same dose during the study as they had prior to enrolment. Dose taken once a day for 10-16 days. intervention 2: Seroquel IR dose 400-700 mg (in tablet form). The investigator established the dosing schedule for each patient depending on the patient's dose when entering the study. The patients continued on the same dose during the study as they had prior to enrolment. Dose taken twice a day for 10-16 days. intervention 3: Placebo matching Seroquel XR dose 400-700 mg (in tablet form). Dose taken once a day for 10-16 days. intervention 4: Placebo matching Seroquel IR dose 400-700 mg (in tablet form). Dose taken twice a day for 10-16 days.

Protocol document: