Byerly 2008.

Methods	Allocation: randomised. Blinding: double blind. Duration: 6 weeks. Design: parallel, 1 week cross taper for patients randomised to quetiapine switch. Setting: outpatients; USA.
Participants	Diagnosis: DSM‐IV diagnosis of schizophrenia or schizoaffective disorder and risperidone‐associated sexual dysfunction. History: participants with schizoaffective disorder must have received a stable dose of antimanic and/or antidepressant medication for ≥30 days prior to study entry and have experienced stability of mood symptoms for >2 weeks prior to baseline assessments. Written informed consent from patients was obtained. N = 42. Age: 24 to 58 years (mean 42.3 SD 9.6). Sex: 22 men, 20 women. Inclusion criteria: at least 18 years old, moderate sexual dysfunction (ASEX total score ≥ 15), risperidone only antipsychotic ≤ 4 mg/ day (unless history justified higher dose). Participants were excluded if they received a long‐acting injectable antipsychotic within one dosing interval of intended study entry.
Interventions	1. Switching to quetiapine (to 300 mg/day week 1 and 2, 800 mg/day maximum allowable). N = 22. 2. Risperidone continuation (dose continued from pre‐study, N = 20.
Outcomes	Leaving the study early Sexual function (subjective assessment): ASEX Sexual function (surrogate assessment): Prolactin levels (ng/mL) Adverse effects: Psychopathology ‐ PANSS
Notes	Data were collected over a 3‐year period from May 2002 to October 2005. *Reported in a sub‐sample of participants.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomized", method not reported.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"Double blind". "Blinding to treatment group was maintained through the use of identical appearing capsules."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	ASEX: “ study utilized self administered questionnaire cards that participants read silently to themselves. The participants then reported only the scale number that corresponded to their experience for each ASEX item” PANSS: collection method not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses to follow‐up reported, but 2 missing observations for ASEX at 6 weeks in the risperidone group; 4 missing observations for ASEX at 6 weeks in the quetiapine group.
Selective reporting (reporting bias)	High risk	All stated outcomes reported. For ASEX there were missing observations and no reasons given for this. Prolactin levels reported in a sub‐sample of participants.
Other bias	High risk	Funded by NIMH K‐Award grant # 5 K23 MH064930, the Stanley Medical Research Institute, the Betty Jo Hay Distinguished Chair in Mental Health, Mental Health Connections, a partnership between Dallas County Mental Health and Mental Retardation (MHMR) and the Department of Psychiatry of the University of Texas Southwestern Medical Center, and AstraZeneca LP. (ISS study number DIRUSQUET0186)