This study aimed to conduct a qualitative evaluation of the health care in the structure and care process indicators of the nursing staff in a psychiatric unit of a General Hospital for people with mental disorder, and use of alcohol and other psychoactive substances in situations of hospitalization considering the epidemiological profile of the attended cases, in the possibility of approximation with the reality experienced by the nursing staff, the knowledge and the safety that exists in its performance regarding mental health care, alcohol and other drugs. This is a descriptive and exploratory research with a predominant qualitative approach, but encompasses a multiple methods or multi-method modality. It had as research place an existing UPHG in Brazil. The study population was a sample of 10 nursing team professionals; nurses and nursing technicians working in the internment unit. The participants involved were informed about the research objectives and certified of the voluntary participation, signing as an agreement, an Informed Consent. Data analysis was based on descriptive steps of qualitative data analysis, with the coding and segmentation of the obtained material, guided by the research findings. Enabling a discussion about the limitations and potentialities identified in nursing care in psychiatric units is indispensable to postulate a resignification of such care in mental health, alcohol and other drugs in the UPHG, such as the sedimentation of the need to know -how to hear, to listen, to observe, to take care of, for better professional qualification; positioning of the nursing professional from admission to discharge as a guiding member of care in the UP, regarding both organizational and care aspects related to mental health.