Abstract
The construction industry is widely recognised as one of the most physically and psychologically demanding sectors. Yet, limited empirical attention has been given to the relationship between mental health, well-being, and productivity within the Nigerian construction industry. This study investigated that relationship among construction project teams and considered strategies to protect psychological well-being and performance. A mixed-methods design was adopted, combining a structured survey of 150 construction professionals across project sites in Abuja and other Nigerian cities with an expert-informed scenario analysis. The literature review was guided by the Job Demands–Resources model and Psychosocial Safety Climate theory. Quantitative data were analysed using descriptive statistics and multiple linear regression; the expert scenario material was organised thematically. Regression results showed that job role, education, experience, and weekly working hours explained less than 10 percent of the variance in worker satisfaction (R² = 0.085), productivity (R² = 0.040), and mental well-being (R² = 0.079), and none of the models reached statistical significance indicating that these demographic and occupational variables do not meaningfully predict the outcomes studied. The expert-informed scenarios provide a plausible interpretation of the unexplained variance by suggesting that factors such as leadership quality, workload distribution, fatigue, team coordination, and organisational culture may also influence the outcome. These illustrative explanations are consistent with the study's guiding theoretical framework. The study therefore recommends the integration of psychosocial risk management, supportive leadership training, fatigue and welfare management, structured team coordination, and mental health awareness programmes into construction project management practice in Nigeria.

Key words: Mental health, Psychological wellbeing, Productivity, Construction project teams, Nigeria. Occupational stress.