Aim of the study is to assess the effect of quetiapine treatment in neuroleptic naive, first-episode schizophrenic patients on aspects of functional and structural neuroplasticity assessed by means of transcranial magnetic stimulation and voxel-based morphometry. Main outcome measure is a change in gray matter density under quetiapine treatment from baseline to steady-state-treatment after 3 weeks.

Inclusion Criteria:

• diagnosis of first episode of schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders- Fourth Edition (DSM-IV) criteria and no history of neuroleptic medication
• Females and/or males aged 18 to 65 years
• Mild to moderate schizophrenia

Exclusion Criteria:

• Neuroleptic treatment prior to study enrollment
• Pregnancy or lactation
• Any DSM-IV Axis I disorder not defined in the inclusion criteria
• Patients who, in the opinion of the investigator, pose an imminent risk of suicide or a danger to self or others
• Known intolerance or lack of response to quetiapine fumarate as judged by the investigator
• Use of any of the following cytochrome P450 3A4 inhibitors in the 14 days preceding enrolment including but not limited to: ketoconazole, itraconazole, fluconazole, erythromycin, clarithromycin, troleandomycin, indinavir, nelfinavir, ritonavir, fluvoxamine and saquinavir
• Use of any of the following cytochrome P450 inducers in the 14 days preceding enrolment including but not limited to: phenytoin, carbamazepine, barbiturates, rifampin, St. John's Wort, and glucocorticoids
• Any history of neuroleptic treatment
• Substance or alcohol dependence at enrollment (except dependence in full remission, and except for caffeine or nicotine dependence), as defined by DSM-IV criteria
• Opiates, amphetamine, barbiturate, cocaine, cannabis, or hallucinogen abuse by DSM-IV criteria within 4 weeks prior to enrollment
• Medical conditions that would affect absorption, distribution, metabolism, or excretion of study treatment
• Unstable or inadequately treated medical illness (e.g. angina pectoris, hypertension, congestive heart failure) as judged by the investigator
• Involvement in the planning and conduct of the study
• History of or evidence of significant brain malformation or neoplasm, head injury, cerebral vascular events, neurodegenerative disorder affecting the brain or prior brain surgery
• Concomitant treatment with psychotropic drugs (e.g. antidepressive agents, anticonvulsants, other neuroleptics) except benzodiazepines or hypnotics