Antipsychotics (AP) are frequently used in Quebec long-term care centres (LCT), especially in older residents with major neurocognitive disorders (MNCD), and behavioural and psychological symptoms of dementia (BPSD), with prevalence up to 50%. There are issues related to the prescription of APs: They are associated with adverse health events, high costs and poor quality of life; their appropriateness is often questioned because due to poor efficacy and safety concerns. Their high prevalence is an indicator of suboptimal care. In 2017, the Quebec Health and Social Services Ministry in partnership with the Canadian Foundation for Healthcare Improvement launched the pilot phase of OPUSAP in 24 LTC with the overall objective to 1) Improve the appropriateness of AP use in older residents with MNCD and BPSD and 2) Prioritize the use of non-pharmacological interventions. OPUS-AP is a conference and webinar-based training (integrated knowledge) program designed to mentor healthcare personnel (i.e., physicians, pharmacologists, nurses, physiotherapists, orderlies) which has been designed to: 1) Improve knowledge on the optimal use of AP, 2) Provide guidelines on AP deprescribing, and use of patient-centred care and non-pharmacological interventions to treat BPSD. OPUS-AP is a solution designed to develop standardized and objective best practices using a structured online assessment with recurring assessments of health condition and AP prescription in LTC residents, as well as of the occurrence of adverse health events including falls, admission in acute care and death. OPUS-AP is an epidemiologic method of monitoring of the evolution of AP prescription and health condition in older residents living in LTC, and changes in professional practices.