Cognitive impairment is common in individuals presenting to alcohol and other drug (AOD) settings and the presence of biopsychosocial complexity and health inequities can complicate the experience of symptoms and access to treatment services. A challenge for neuropsychologists in these settings is to evaluate the likely individual contribution of these factors to cognition when providing an opinion regarding diagnoses such as acquired brain injury (ABI). This study therefore aimed to identify predictors of cognitive functioning in AOD clients attending for neuropsychological assessment.

Clinical data from 200 clients with AOD histories who attended for assessment between 2014 and 2018 were analysed and a series of multiple regressions were conducted to explore predictors of cognitive impairment including demographic, diagnostic, substance use, medication, and mental health variables.

Regression modelling identified age, gender, years of education, age of first use, days of abstinence, sedative load, emotional distress and diagnoses of ABI and developmental disorders as contributing to aspects of neuropsychological functioning. Significant models were obtained for verbal intellectual functioning (Adj R2 = 0.19), nonverbal intellectual functioning (Adj R2 = 0.10), information processing speed (Adj R2 = 0.20), working memory (Adj R2 = 0.05), verbal recall (Adj R2 = 0.08), visual recall (Adj R2 = 0.22), divided attention (Adj R2 = 0.14), and cognitive inhibition (Adj R2 = 0.07).

These findings highlight the importance of careful provision of diagnoses in clients with AOD histories who have high levels of unmet clinical needs. They demonstrate the interaction of premorbid and potentially modifiable comorbid factors such as emotional distress and prescription medication on cognition. Ensuring that modifiable risk factors for cognitive impairment are managed may reduce experiences of cognitive impairment and improve diagnostic clarity.