Objective: To examine and analyze the factors that predict mental health and psychiatric nursing competencies of professional nurses in psychiatric hospitals, southern Thailand.
Material and Methods: The study sample was composed of 128 professional nurses working in psychiatric hospitals, southern Thailand. Instruments included two parts: a demographic data form, and a mental health and psychiatric nursing competent questionnaire, which was developed by the researcher based on literature review. The mental health and psychiatric nursing competence was scored on a scale of 1-3. Content validity was verified by 3 experts. Internal consistency of the mental health and psychiatric nursing competent questionnaire was tested using Cronbach's alpha coefficient, which gave a value of 0.94. Data were analyzed using basic descriptive statistics and stepwise multiple regression.
Results: Professional nurses in psychiatric hospitals, southern Thailand have a high level of overall mental health and psychiatric nursing competencies (X = 2.57, S.D. = 0.29). Subjects perceived their highest level of competence in the component of psychiatric nursing documentation (X = 2.64, S.D. = 0.35), followed by culture related nursing care component (X = 2.60, S.D. = 0.39). Mental health promotion and psychiatric illness prevention were rated as the lowest level (X = 2.45, S.D. = 0.43).

Stepwise multiple regression analysis revealed that thirty-one percent of variance of mental health and psychiatric nursing competencies was accounted by two factors: experience on working with psychiatric patients and nursing educational level.
Conclusion: The mental health and psychiatric nursing competencies of professional nurses in psychiatric hospitals, southern Thailand, both in general and also in each components of mental health and psychiatric nursing competence, were shown to be at a high level. The mean score of components of psychiatric nursing documentation was the highest, followed by the culture related nursing care component. Only experience in working with psychiatric patients and nursing educational level can predict mental health and psychiatric nursing competencies of professional nurses in psychiatric hospitals, southern Thailand. The results can be used to enhance all components of nurses' competence equally. Nurse administrators should be concerned with experiences in mental health and psychiatric nursing practices and promote nursing education for nurses.