A comparison study of quetiapine medication and psychological therapy versus placebo tablets and psychological therapy in patients who are deemed at risk of developing a psychotic disorder.

To investigate the effect of quetiapine, in addition to CBCM (cognitive behavioural case management) on the incidence of first episode psychosis. The quetiapine dose will be flexible at the discretion of the treating clinician (within the 50-400mg range). Patients will commence on a dose of 50mg per day. This will gradually be titrated upwards in increments of 50mg per week with 400mg as the maximum dose. Note that 400mg is the mximum dose and therefore not necessarily the ideal dose for each patient. Duration of treatment will be over a 6 month period. The mode of administration will be oral capsules. Cognitive Behavioural Case Management (CBCM) is a psychological treatment that incorporates Cognitive Behaviour Therapy (CBT) into case management, and will be provided by the clinician on a one-on-one (approximately one hour) weekly session for 6 months, and then on an "as needs" basis for up to 12 months from entry. A standardised manual has been developed by Orygen to ensure consistency across all sites.