Abstract
Substance use (SU) is a widespread occupational and public health problem among manual workers, including bricklayers in Nigeria, and is often related to irregular working conditions (IWC) and psychosocial stressors (PsS). This study examined the relationships between IWC, PsS, coping strategies (CS), social support (SS), and SU among 125 bricklayers in Abeokuta, Nigeria, using a cross-sectional survey design. A structured self-report questionnaire was used to collect data on demographics, psychosocial stress, coping behaviour, SS, and SU. Descriptive statistics, bivariate analyses, and structural equation modelling (SEM) analysed the hypothesised model, including mediation and moderation effects. The outcomes revealed that alcohol (48%) and tobacco (40%) were the most frequently used substances, with 16% of participants reporting polysubstance use (PSU) overall. IWC was related to greater SU scores (t = 4.52, p < 0.001). The effects of PsS, including financial, job strain, and discrimination, were positively related to SU (r = 0.29-0.42, p < 0.01). The intervention study found that the impact of PsS on SU was mitigated by CS (β = 0.17, p < 0.001). The moderation analysis reported SS moderated the effect of IWC and PsS on SU (β =-0.21 to-0.25, p < 0.01). The SEM fit scores showed a very good match (CFI = 0.96, TLI = 0.94, RMSEA = 0.045, SRMR = 0.038). It suggests that the suggested model provided a good match to the connections between the variables. Results suggest that individual workers are at increased risk of the misuse of alcohol and/or drugs when faced with adverse occupational conditions or psychosocial risks, and that the use of adaptive coping skills appeared to be protective, along with the availability of SS. Recommendations for a workplace intervention include the reduction in occupational hazards, helping workers improve coping skills, and increasing SS as a means to reduce the misuse of substances among bricklayers in Abeokuta.