The mediating role of impulsivity on suicidal behaviour among higher education students with depression and substance abuse disorders.

Background
Alcohol and drug dependent individuals have consistently exhibited elevated impulsivity and some studies have indicated that impulsivity recorded in young adults predicts future alcohol abuse. Research also indicates that depressed individuals with higher impulsivity are more likely to report suicidal ideation even when they are less depressed, which may indicate that impulsivity could more strongly predict suicidality than severity of depressive symptoms.

Objective
The aim of this study was to investigate the mediating role of impulsivity on suicidal behaviour and self-harm among students with depression, alcohol and substance abuse disorders.

Materials and methods
Participants were first-year undergraduate students (n = 1829) across Ulster University (NI) and Letterkenny Institute of Technology - now known as Atlantic Technological University Donegal (ROI), who were recruited as part of the World Mental Health International College Student Initiative. Participants completed an online survey utilising the WMH-Composite International Diagnostic Interview Screening Scales (CIDI-SC). Mediation analyses were conducted in three different stages.

Results
A high prevalence of depression and substance use disorders, suicidal ideation, plans, attempts and self-harm were observed. Impulsivity was found to partially mediate the association between depression and suicidal behaviours and substance use disorders and suicidal behaviours. Impulsivity was significantly associated with suicide ideation, attempts and self-harm, but not suicide plans. Males were more likely to be impulsive, and higher levels of depression and substance use disorders were related to higher impulsivity.

Conclusions
The main findings of this study reinforce the role of impulsivity in mediating the relationship between depression and suicidality and substance use and suicidality. College wellbeing services may consider whether screening for impulsivity, rather than for example substance abuse, could be more beneficial and less prone to under-reporting, when assessing for suicide risk among vulnerable students.