Schizophrenia accounts for a significant portion of the global burden of neuropsychiatric disorders. It is often refractory to treatment and relapse due to poor adherence is also common. In addition, treatments for schizophrenia are frequently associated with side effects that can cause serious medical problems, such as cardiovascular disease. Quetiapine is approved for the treatment of schizophrenia and impacts a broad range of symptoms that affect quality of life.

Peuskens J et al. (NR4–054) reported that patients with stable schizophrenia who were treated with quetiapine ER (400–800 mg/day) had lower relapse rates (11.7% vs 48.5%) and significantly longer time to relapse versus placebo after 1 year of treatment (HR 0.13; 95% CI 07, 0.26; p<0.001). Loss of symptomatic remission, as defined by the Andreasen Remission Criteria [Andreasen NC et al. Am J Psychiatry 2005], occurred in 16.4% of quetiapine versus 29.9% of placebo patients. Time to loss was significantly shorter with placebo versus quetiapine ER (HR 0.3; (95% CI 0.19, 0.81); p<0.001).

In a similar patient population, Kalai A et al. (NR4–002) reported that quetiapine XR (400, 600, and 800 mg) and IR (400 mg) daily significantly reduced mean PANSS total score from baseline to Week 6 (p<0.01). Quetiapine XR (all doses) also produced a significant reduction in PANSS aggression and hostility scores. These improvements were not dependent on illness severity.

Falkai P et al. (NR4–027) reported that after 12 weeks of quetiapine (median 600 mg/day) treatment, 58.3% of patients with acute schizophrenia achieved resolution (defined as ≤3 on each of the 8 items of the PANSS). Significant baseline predictors of resolution included: younger age, having a first episode and shorter duration of episode, paranoid subtype of schizophrenia, lower PANSS-8 total score, and lower severity of CGI-S. A high number of previous hospitalizations, residuum subtype of schizophrenia, alcohol abuse, and concomitant disease predicted non-resolution.

Järbink K et al. (NR4–058) reported the results of a 12-week cost-utility analysis in patients who switched from another antipsychotic to quetiapine (66% for lack of efficacy; 34% for tolerability), which showed significant QALY gains, irrespective of the reason for the switch. QALY gains were measured using PANSS score, the presence of adverse events, and methods established by Lenert et al. [Schizophr Res 2004; Health Qual Life Outcomes 2005].