The project examined the effects of regular alcohol and/or cannabis use on behavioural control, memory, and attention processes, and on brain function in young adults.
Much is known about the brain functional impacts of alcohol and cannabis use in older adults; less is known about the impacts on use among young adults. We combine powerful behavioural tests with sensitive measures of brain electrical activity; research has shown that these may index changes in brain function before these are significant enough to affect behaviour.
The study will provide new knowledge on the extent of cognitive deficits associated with alcohol and cannabis use in young people, as prior research in this area focuses on (a) older, more established/dependent users and (b) memory function alone. Our research will examine a younger cohort with less exposure to alcohol and cannabis, but who are potentially at more risk of damage to their still-developing brains. Secondly, we combine assessment of not only memory but also executive function processes, as these are becoming increasingly important in models of the development and maintenance of substance dependence.
Participants aged 18-21 will be recruited into three groups: (a) regular heavy drinkers, (b) regular cannabis users, and (c) low-level/non-drinker and non-cannabis users. All participants complete tests of memory, behavioural control, attentional control, and decision making, while brain electrical activity is recorded.
We completed data collection from 98 participants in late 2014. Data analysed so far suggests: (a) impaired short term memory, and impaired long-term memory for the source of information in heavy drinkers; (b) impaired behavioural control in heavy drinkers but not cannabis users, relative to controls; (c) sex differences are apparent in impairments in behavioural control in heavy drinkers, with females being more impaired.
Smith JL & Mattick RP (2013) Evidence of deficits in behavioural inhibition and performance monitoring in young female heavy drinkers. Drug and Alcohol Dependence, 133(2): 398-404. doi:10.1016/j.drugalcdep.2013.06.020
Smith JL, Iredale JM & Mattick RP (submitted Dec 18 2014) Heavy alcohol use is not associated with cognitive deficits in young males: Behavioural inhibition and performance monitoring. Psychiatry Research: Neuroimaging.
Smith JL, Iredale JM & Mattick RP. Heavy alcohol use is not associated with disinhibition in young males (platform). 24th Australasian Society for Psychophysiology conference, Coffs Harbour, Australia, Nov 26-28, 2014.
Smith JL. Behavioural and brain indices of impaired control in young heavy drinkers. (invited speaker). Brain Sciences UNSW colloquium, Jul 7, 2014.
Smith JL, Mattick RP & Iredale JM. Electrophysiological evidence of subtle deficits in memory processes in young heavy drinkers and cannabis users (platform), Australasian Professional Society on Alcohol and other Drugs, Brisbane, Australia, Nov 24-27, 2013.
Smith JL, Mattick RP & Iredale JM. Electrophysiological evidence of subtle deficits in memory processes in young heavy drinkers and cannabis users (platform), 23rd Australasian Society for Psychophysiology conference, Wollongong, Australia, Nov 20-22, 2013.
Smith JL, Iredale JM & Mattick RP. Electrophysiological evidence of subtle deficits in recognition memory processes in young heavy drinkers and cannabis users (poster),Brain Sciences UNSW Symposium, Sydney, Australia, Oct 18, 2013.
Smith JL, Iredale JM & Mattick RP. Electrophysiological evidence of subtle deficits in recognition memory processes in young heavy drinkers and cannabis users (poster),NDARC Symposium, Sydney, Australia, Sep 4, 2013.
The study will provide up-to-date information about the nature and extent of deficits in non-treatment-seeking young people who have far less experience with drugs and alcohol than many participants in previous studies.