Australian Rotary Health/Rotary District 9685 Funding Partner PhD Scholarship recipient, Ivana Kihas, uses four stages of study to significantly advance the understanding of the prevalence and patterns of comorbidity between Substance Use Disorder (SUD), Eating Disorders (ED), and Post-Traumatic Stress Disorder (PTSD) and lay the foundations for targeted and effective prevention and intervention strategies that will lessen the significant burden, harms, and costs associated with these disorders.

Study 1: A systematic review of 58 studies examining the prevalence and patterns of co-occurring substance use and disordered eating/EDs among young people. The review identified high prevalence rates of co-occurrence across all non-clinical groups (community populations, high-school students, and university students). Four patterns were evident: i) in samples reporting disordered eating, substance use was more prevalent and frequent; ii) greater disordered eating severity was related to higher substance use frequency; iii) binge eating and purging were highly related to alcohol, tobacco, and other drug use; and iv) binge behaviours (i.e., binge eating and binge drinking) were highly related among all samples. Several methodological flaws and gaps were identified: i) an absence of research examining the role of trauma; ii) substance use mainly explored in samples with disordered eating and not vice versa; iii) no standardised way of measuring disordered eating among young people.

Study 2: Showed substance use, SUDs, trauma, and PTSD are prevalent among a large community cohort of young people. Overall, the results showed that substance use is associated with having experienced any traumatic event, particularly sexual and physical types of traumatic events, and developing PTSD. While the use of all substances was found to be associated with some, or all, of the trauma variables, cannabis use was most associated with these variables. Having experienced sexual trauma was the only trauma type significantly associated with all substance use variables, including binge drinking. SUDs were highly prevalent among this group of young people, with over one-third (36%) of the sample having met criteria for a probable diagnosis for an SUD. This estimate is over three times higher than the 9% observed among Australian’s aged 16-24 years in the general population. These important implications highlight that SUD and PTSD are common among a community sample of young people.

Lastly, studies 3-4 examine cross-sectional and longitudinal associations between substance use, SUD symptom severity, PTSD symptom severity, post-traumatic cognitions, and disordered eating. In a clinical sample of young people with severe SUD and PTSD, approximately half of the sample reported disordered eating behaviours and one in five met criteria for a probable ED. Higher disordered eating scores were associated with experiencing a sexual trauma, as well as post-traumatic negative cognitions. A reduction in negative post-traumatic cognitions was associated with a reduction on the disordered eating scale, over a 4-month period.

While both substance use/SUDs and trauma experiences/PTSD are highly prevalent, among a non-clinical and highly functioning group of young people, demonstrating that targeted prevention and intervention may need to occur before emerging adulthood age. The occurrence of disordered eating and probable ED is also clear in a clinical sample of people with SUD and PTSD and warrants more attention to help treat this complex co-occurrence of disorders.

Media contact: [email protected]       First published 19th February 2024