OBJECTIVES: Drug choice and adherence are important aspects in schizophrenia and bipolar disorder (BD) and depend on patient and drug characteristics. Our aim was to examine Nordic psychiatrists’ views on treatment choice, adherence, once daily dosing (ODD), and the use of extended release (XR) and instant release (IR) quetiapine. METHODS: We conducted a quantitative, telephone-based survey with 201 respondents randomly selected from a list of all 1906 Swedish and 677 Danish psychiatrists (excluding child and geriatric psychiatrists). Structured, one-hour qualitative interviews with 10 psychiatrists per country allowed us to further interpret the results. Data was collected by an independent research company. For binary variables, we performed a binomial test of the null hypothesis that the alternative responses were equally likely. RESULTS: One hundred one Danish and 100 Swedish psychiatrists were included; 65% were male and the mean (SD) psychiatric experience was 15.4 (8.2) years. No relevant country differences were found. 198 psychiatrists (99%) agreed on the importance of individualized treatment (p≤0.0001). Respondents reported that 42% of schizophrenia and 33% of BD patients tried ≥3 antipsychotics before being stabilized. All respondents reported non-adherence to be common and all associated non-adherence with side-effects. 199 (99%) psychiatrists thought that ODD would improve adherence (p≤0.0001), and 196 (98%) that it could mitigate partial adherence problems (p≤0.0001). 179 respondents (89%) said that ODD reduces relapse rates (p≤0.0001). A total of 147 psychiatrists (73%) associated quetiapine XR with less day sedation than IR (p≤0.0001), and 132 (66%) associated XR with a reduced need for injection treatment (p≤0.0001). In the qualitative interviews, XR was to a higher extent associated with antipsychotic monotherapy and IR more often with short-term use for e.g., sedation. CONCLUSIONS: Nordic psychiatrists considered individualized drug therapies in schizophrenia and BD to be important and perceived ODD to improve adherence. Respondents associated quetiapine XR with differential use compared to IR.