|dc.description.abstract||The aim of this thesis is to examine the neuropsychological profiles of psychosis patients, with and without current cannabis use. Specifically, to determine how age may moderate the effects of cannabis use on neurocognition. In normal populations, cannabis use has been shown to provoke deficiencies across a range of cognitive domains. However, patients diagnosed with a psychotic disorder, who have a history of, but then abstain from cannabis use, demonstrate cognition that is seemingly superior to their cannabis-naïve peers. In some cases, comorbid patients exhibit neurocognition similar to control subjects.
The first study of this thesis (i.e. Chapter 2) is a meta-analysis that investigates neuropsychological data reporting on current cannabis-using and cannabis-naive psychosis patients. It was hypothesized that comorbid patients would demonstrate significant deficits across a range of neurocognitive tests, compared to non-using patients. It was found that current cannabis-using patients underperformed across 6 of the 11 cognitive domains compared to cannabis-naïve patients. Meta-regressions showed older age in cannabis-using patients was predictive of worse performance in processing speed, sustained attention, verbal memory, and better performance in verbal learning and verbal fluency. Importantly, it appears this is exacerbated with increasing age.
In the second study (i.e. Chapter 3), psychosis patients were exclusively between 16 and 25 years of age. The patients underwent neurocognitive assessments to compare cognition between drug-naïve patients and comorbid patients. It was expected comorbid psychosis patients and cannabis-naïve patients would demonstrate no significant neurocognitive differences. Patients were administered a neurocognitive battery, indexing estimated several cognitive domains. The findings indicated no significant neurocognitive differences between the two clinical psychosis groups.
Ultimately, previous studies reporting superior cognition in patients with a history of cannabis use, and the current thesis demonstrating no cognitive differences between patients regardless of concurrent cannabis use, taken together suggest the notion of psychosis-onset, and subsequent schizophrenia, initiated by early cannabis onset.||en_AU|
|dc.publisher||University of Sydney||en_AU|
|dc.publisher||Faculty of Medicine and Health||en_AU|
|dc.publisher||Brain and Mind Centre||en_AU|
|dc.rights||The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.||en_AU|
|dc.subject.other||POST DG EXPORT SUBMISSION||en_AU|
|dc.title||A Comprehensive Analysis of Neurocognition in Young Psychosis Patients with Current Cannabis Use||en_AU|
|dc.type.pubtype||Master of Philosophy M.Phil||en_AU|
|Appears in Collections:||Sydney Digital Theses (Open Access)|