During the last years the atypical antipsychotics also known as second generation antipsychotics together with first generation antipsychotics have occupied a special position in the treatment of psychotic disorders. Purpose: Assessment of the severity and evolution of symptoms in schizophrenia based on BPRS scale (Brief Psychiatry Rating Scale) and CGI scale (Clinical Global Impression during Seroquel treatment in common clinical practice. Objective: Assess the severity of the patient’s schizophrenia at the time when they entered the study and after the administration of treatment, using the scores obtained after the CGI scale application. Material and method: Non-interventional observational study conducted at „Socola” Hospital of Iasi. 138 patients were involved (male and female), with ages > 18 years, newly diagnosed or with a recorded diagnosis of schizophrenia, irrespective of the clinical form, according to the criteria of DSM VI. The patients involved in the study have received doses ranging between 400 and 750 mg/day of Seroquel for 24 weeks, with a previous period of titration, being assessed throughout 6 patient rounds according to common clinical practice. Results and conclusions: The administration of Seroquel determined a clear improvement of the clinical condition, shown by the decrease of BPRS and CGI scales at the 6 rounds. At the end of the 24 weeks of treatment with Seroquel, the average BPRS score was of 16,96 compared to 45,02 at the beginning of the program. Throughout the study, the severity of the illness assessed according to CGI scale was diminished for most patients. At the beginning of the study 93 % of patients without previous antipsychotic medication and respectively 96 % of patients with previous antipsychotic medication had a moderate to very severe illness (CGI-S score > 4). At the end of the study 76.2 % of patients without previous antipsychotic medication and respectively 77.8 % of patients with previous antipsychotic medication had only a mild degree of illness, at the borderline of pathology or were normal from a clinical perspective (CGI score <3). The reduction of the illness’ severity was similar for the two groups of patients with or without previous medication. The score of the clinical global impression improvement (CGI-I) had a positive evolution for more than 96 % of the rated patients. The data were processed and statistically studied, finding a significant statistical difference in the decreasing evolution of BPRS scores from one round to another. The comparative study of BPRS scores between the two groups with or without previous medication, showed that patients without previous had significantly lower scores after 5 moths (p= 0.013) and respectively 6 months (p=0.002) of therapy with Seroquel. This pointed out that although their initial symptoms were more severe in comparison with the patients receiving medication (BPRS score considerably higher, p=0.002) the therapeutic benefit was a lot more significant after 5 months of treatment. Efficiency of Quetiapine in Schizophrenia – Clinical Trial 47 This study demonstrates the efficiency of Seroquel for patients with schizophrenia-related disorders. At the same time, it is a secure and well-tolerated antipsychotic medication. All these facts represent factors of favorable prognosis, forecasting a positive evolution of the illness preventing the appearance of subsequent relapse.