Background: Substance use and mental disorders are highly prevalent in Thai homeless people living with no mental health recovery. The lack of psychosocial occupational therapists may be one huge problem for none of the measurement outcomes for clinical utility. We aimed to determine the known group validity of the Assessment of Work Performance (AWP) with good content and internal consistency reliability. Methods: Participants (N = 60) were recruited by screening with no cognitive impairment, no psychiatric symptoms, independent selfcare, and on the job assignment at Nonthaburi destitute home. Mann Whitney U tests firstly found a significant difference in process skills between males and females (p < .05). Data analysis of the ceiling effect was then conducted to design using cleaned samples (N = 22), and the Mann Whitney U tests secondly found a significant difference in communication skills between males and females (p < .05). Results: There were no associations between the frequency of genders and substance abusers were computed using cross tabulation (N = 60 versus N = 22). Besides a corrected sample, natural contexts of too easy job selection, no preparatory of supported employment, and non purposeful living activities may be confounding factors of avolition, poor habit, and inactive life roles without wellness at the end of life. Conclusion: These preliminary results suggest a useful AWP with good known group validity for measuring outcomes among vulnerable people and describing how to improve motor, process, and interactive communication skills based on the Model of Human Occupation (MOHO) in occupational therapists and Mental Health Recovery (MHR) workers.

The authors have declared no competing interest.

This project was made possible by funding for a new researcher at the Faculty of Physical Therapy, Mahidol University in the fiscal year 2024.

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This study has received ethical approval from the Mahidol University Central Institutional Review Board (COE No. MU-CIRB 2023/186.2212).

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