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.

Previous studies on substance-dependent populations have shown that age of first use and duration of use are associated with alterations in regional brain volumes. However, it is not clear whether such alterations are factors that predispose young people to use, and so are also present in recreational users, or are a consequence of chronic exposure to substances and/or comorbid psychopathology.

To investigate relationships between key brain structures and parameters of alcohol and cannabis use, in otherwise healthy male recreational users.

High-resolution magnetic resonance imaging was used to measure hippocampal, amygdala, whole-brain and intracranial cavity (ICC) volumes in 22 young men with a history of both alcohol and cannabis use.

Linear regression analyses with hippocampal, amygdala and whole-brain volumes as the dependent variables and age and ICC as covariates were performed. Findings showed that use of cannabis and alcohol at an earlier age were independently predictive of larger amygdala volumes, whereas longer duration of cannabis use was predictive of smaller hippocampal volumes.

Our findings offer preliminary support for a relationship between patterns of substance use and regional brain volumes in recreational users. It is speculative, but possible that this relationship is an evidence of a neurobiological vulnerability to drug-taking behaviour.

To illustrate the need to carefully consider mental health, psychosocial and motivational factors when investigating cognitive and intellectual impairment among chronic inhalant users.

Two adolescent chronic inhalant users with similar psychosocial disadvantages (eg unstable and dysfunctional families, state-based care, school absenteeism and forensic issues) and histories of comorbid drug use and mental health problems were assessed using a battery of paper and pencil and computerised neuropsychological tests.

Contrary to the expectations of her case manager, one participant performed within the normal range for her age in all domains of intellectual ability, while the other participant, in line with the expectations of her case manger, showed marked cognitive deficits and intellectual disability.

The typically complex presentation of chronic inhalant users (ie disadvantaged psychosocial backgrounds, comorbid psychopathology and poor motivation/engagement) is rarely considered when investigating associated cognitive and intellectual functioning. Future research should more carefully consider the role of such factors, given the evidence suggesting that they can considerably alter (accentuate or diminish) the association between inhalant abuse and neuropsychological impairment.

Drug-related stimuli reliably induce craving in experimental paradigms, yet are rarely cited by drug users as major precipitants of relapse. We examined the motivational significance of drug cues in opiate dependence, by exploring their impact on central attentional processes.

Fourteen methadone-maintained subjects and 14 matched controls were studied. Subjects performed a novel active visual oddball task, consisting of opiate-related and matched neutral pictures, some of which (the oddballs) included a white cup. Subjects were fitted with a 32-channel electrode cap. The P300 for each stimulus category was identified using temporal principal components analysis.

The P300 elicited by opiate stimuli was significantly larger than that elicited by neutral stimuli in the methadone-maintained group but not in the controls. There was also a non-significant trend for the opiate stimuli to elicit larger P300s than the oddball stimuli in the addicted group.

These results suggest that drug cues acquire motivational salience and automatically capture attentional resources in opiate addicts, even when engaged in a non-drug-related task. Enhanced P300s to drug cues may provide an important biological marker of crucial psychological mechanisms relevant to addiction.