Abstract
Over the years, studies have identified posttraumatic stress disorder as one of the greatest problems in military and police
population worldwide. Apparently, extant literature have associated this problem with combat exposure; however, what is
still unclear is whether adopting certain coping strategies like substance use after homecoming from combat deployment
could increase vulnerability to combat-related PTSD especially among Nigerian police population that has been associated
with high substance use coping. This study therefore examined the mediatory role of substance use coping in the relationship
between combat exposure and posttraumatic stress disorder among Nigerian mobile police personnel exposed to Boko
Haram insurgency in the North-eastern, Nigeria. Data were collected using standardized questionnaires on a sample of 630
participants. Two hypotheses were stated and analysed using Pearson correlation, linear and hierarchical multiple
regression, and results revealed a significant positive relationship between combat exposure (r= .36; p<.01), substance use
coping (r=.28; p<.01) and PTSD; as well as combat exposure and substance use(r= .19; p<.05). Additional findings indicated
that combat exposure (β=.09, t= 2.2; p<.05) and substance use coping strategy (β= .26, t= 6.74; p<.01) independently and
jointly [F(1,622)= 29.05; R.29, R2=.09; p<.01] influenced PTSD, and that substance use coping significantly mediated the
relationship between combat exposure (β1= .136**, β2= .85*) as indicated by a significant reduction in the beta values. This
shows that police personnel who experience combat and resort to substance use to cope are more vulnerable to PTSD. Thus,
police authorities must restrain use of substance coping to reduce vulnerability to combat-related PTSD.