There is a growing expectation of implementing shared decision making (SDM) in today's health care service, including mental health care. Traditional understanding of SDM may be too narrow to capture the complexity of treatments of mental health problems. Although the patients' contribution to SDM is well described, the contribution from the health care practitioners is less explored. Therefore, our aim was to explore the attitudes of practitioners in mental health care and the associations between practitioners' attitudes and SDM. We performed a cross-sectional study where practitioners reported their sharing and caring attitudes on the Patient-Practitioner Orientation Scale (PPOS) and age, gender, profession, and clinical working site. The patients reported SDM using the CollaboRate tool. We used a mixed effect model linking the data from each practitioner to one or more patients. We presented the findings and used them as background for a more philosophic reflection. We included 312 practitioners with mean age 46.1years. Of the practitioners, 60 held a medical doctors degree, 97 were psychologists, and 127 held a college degree in nursing, social science, or pedagogy. Female practitioners reported higher sharing (4.79 vs 4.67 [range 1-6], P=.04) and caring scores (4.77 vs 4.65 [range 1-6], P=.02) than males. The regression model contained 206 practitioners and 772 patients. We found a higher probability for the patient to report high SDM score if the practitioner reported higher sharing scores, and lower probability if the practitioner worked in ambulatory care. SDM in mental health care is complex and demands multifaceted preparations from practitioners as well as patients. The practitioners' attitudes are not sufficiently explored using one instrument. The positive association between practitioners' patient-centred attitudes and SDM found in this study implies a relevance of the practitioners' attitudes for accomplishment of SDM processes in mental health care.