Further, this study is limited to Swedish psychiatric inpatient care. It could therefore be interesting to study the clinical practice use of the quetiapine formulations in the outpatient setting

as well as in other countries. This retrospective, observational study has provided new insight into the differential use of quetiapine XR versus quetiapine IR in the clinical treatment of patients with schizophrenia in the acute, inpatient setting. Whereas quetiapine #GDC-0068 in vivo keyword# XR is used in significantly higher doses, and as a primary antipsychotic medication, quetiapine IR is used in lower doses, more often as an add-on medication, possibly for its anxiolytic or sedative effects. Polypharmacy was very common in this patient population and reflects the reality for psychiatrists who treat severe Inhibitors,research,lifescience,medical mental illness. This is an important

finding because these severely ill patients are often excluded from traditional RCTs. Our study thus suggests that more knowledge is needed about treatment patterns and patient outcomes in clinical practice, to complement the picture provided by RCTs with their often Inhibitors,research,lifescience,medical highly selected patient populations. The differential quetiapine XR/IR usage is most likely due to differences in titration, dosing, and pharmacological and tolerability profiles. Most likely it also reflects the psychiatrist’s need for treatment choice. An individualized treatment is essential Inhibitors,research,lifescience,medical for treatment success in schizophrenia. Restricting the range of drugs to which psychiatrists have access risks worsening treatment outcomes, according to European psychiatrists [Altamura et al. 2008]. Our study shows that quetiapine XR and quetiapine IR are not substitutes, but complement each other when treating schizophrenia inpatients. Both quetiapine XR and quetiapine IR are needed in clinical practice for the treatment of schizophrenia. Footnotes Funding: Dr Graz.yna Söderbom, Klipspringer AB, rovided medical writing

support funded by AstraZeneca. This study was sponsored by AstraZeneca. Conflict of interest statement: Lars Eriksson (Principal Investigator) has participated Inhibitors,research,lifescience,medical in clinical trials by Janssen, EliLilly, and AstraZeneca; and given lectures and participated in advisory MRIP boards for Janssen, BMS, EliLilly, and AstraZeneca. Andreas Carlborg is a consultant to and has participated in clinical trials by AstraZeneca; and given lectures for Wyeth. Teresa Hallerbäck and Leif Jørgensen are employees of AstraZeneca. This manuscript was prepared in line with guidelines established by the International Committee of Medical Journal Editors (ICMJE) and published in its Uniform Requirements of Manuscripts Submitted to Biomedical Journals. Contributor Information Lars Eriksson, Sahlgrenska University Hospital, Lillhagsparken 3, Hisings-Backa, SE42250, Gothenburg, Sweden. Teresa Hallerbäck, AstraZeneca, Södertälje, Sweden. Leif Jørgensen, AstraZeneca, Södertälje, Sweden.