{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/40951"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/40951","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Cortical Gyrification in Methamphetamine Associated Psychosis: A Potential Neurodevelopmental Biomarker for Risk of Psychosis","abstract":"For many years, methamphetamine associated psychosis (MAP) has been viewed as a symptomatic, genetic, and morphological blueprint for schizophrenia spectrum disorders (SSD) (Aoki et al., 2013; Grant et al., 2012; Uhlmann et al., 2016; Yang et al., 2021). MAP is currently diagnosed as a substance induced disorder; however, many researchers suggest that MAP may represent a transition into SSD following substance use (McKetin, 2018). The current study investigated global and local gyrification indices (GI) as a potential neurodevelopmental biomarker for psychosis vulnerability in three quasi-experimental groups; methamphetamine users without psychosis (n=21), individuals with MAP (n=18) and healthy controls (n=21). Gyrification indices were determined for each participant using Freesurfer 7.2 and compared across groups with age and sex as covariates in a multivariate analysis of co-variance (MANCOVA). The results demonstrate that group membership alone significantly accounts for 32% of the variation in overall gyrification (F(12, 106) = 1.87, p=.06, η²=0.16; Wilk's lambda = 0.68, p=.04). Follow-up ANCOVAs suggest that individuals who use methamphetamine have higher temporal gyrification than MAP and control participants, although this result was not statistically significant. There was also a significant effect of age on gyrification (F(6, 50) = 5.37, p<.01, η²=0.39; Wilk's lambda = .61, p<.01). Further associations between gyrification and age (r=-0.43, p<0.05), cannabis use and temporal gyrification (r=0.29, p<0.05), alcohol use and temporal (r=0.34, p<0.05) and parietal gyrification were found (r=0.26, p<0.05), as well as age of methamphetamine use onset (r=-0.40, p<0.05). These results offer more evidence on the harmful effects of drug use on brain structure, posing new questions around the developmental basis of gyrification and its status as a biomarker for disease.","abstract_html":"For many years, methamphetamine associated psychosis (MAP) has been viewed as a symptomatic, genetic, and morphological blueprint for schizophrenia spectrum disorders (SSD) (Aoki et al., 2013; Grant et al., 2012; Uhlmann et al., 2016; Yang et al., 2021). MAP is currently diagnosed as a substance induced disorder; however, many researchers suggest that MAP may represent a transition into SSD following substance use (McKetin, 2018). The current study investigated global and local gyrification indices (GI) as a potential neurodevelopmental biomarker for psychosis vulnerability in three quasi-experimental groups; methamphetamine users without psychosis (n=21), individuals with MAP (n=18) and healthy controls (n=21). Gyrification indices were determined for each participant using Freesurfer 7.2 and compared across groups with age and sex as covariates in a multivariate analysis of co-variance (MANCOVA). The results demonstrate that group membership alone significantly accounts for 32% of the variation in overall gyrification (F(12, 106) = 1.87, p=.06, η²=0.16; Wilk&#x27;s lambda = 0.68, p=.04). Follow-up ANCOVAs suggest that individuals who use methamphetamine have higher temporal gyrification than MAP and control participants, although this result was not statistically significant. There was also a significant effect of age on gyrification (F(6, 50) = 5.37, p&lt;.01, η²=0.39; Wilk&#x27;s lambda = .61, p&lt;.01). Further associations between gyrification and age (r=-0.43, p&lt;0.05), cannabis use and temporal gyrification (r=0.29, p&lt;0.05), alcohol use and temporal (r=0.34, p&lt;0.05) and parietal gyrification were found (r=0.26, p&lt;0.05), as well as age of methamphetamine use onset (r=-0.40, p&lt;0.05). These results offer more evidence on the harmful effects of drug use on brain structure, posing new questions around the developmental basis of gyrification and its status as a biomarker for disease.","abstract_has_math":false,"creators":["Gribble, Amy"],"institution":"Department of Psychology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Malcolm-Smith, Susan"],"committee_chairs":[],"committee_members":[],"year":2024,"date_issued":"2024","date_published":"2024","updated_at":"2026-07-22T22:23:13Z","subjects":["Psychology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/40951","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Malcolm-Smith, Susan"]},{"key":"dc:creator","label":"Author","values":["Gribble, Amy"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-02-13T13:13:38Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-02-13T13:13:38Z"]},{"key":"dc:date.issued","label":"Date","values":["2024"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Psychology"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Thesis / Dissertation"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Psychology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/40951"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["For many years, methamphetamine associated psychosis (MAP) has been viewed as a symptomatic, genetic, and morphological blueprint for schizophrenia spectrum disorders (SSD) (Aoki et al., 2013; Grant et al., 2012; Uhlmann et al., 2016; Yang et al., 2021). MAP is currently diagnosed as a substance induced disorder; however, many researchers suggest that MAP may represent a transition into SSD following substance use (McKetin, 2018). The current study investigated global and local gyrification indices (GI) as a potential neurodevelopmental biomarker for psychosis vulnerability in three quasi-experimental groups; methamphetamine users without psychosis (n=21), individuals with MAP (n=18) and healthy controls (n=21). Gyrification indices were determined for each participant using Freesurfer 7.2 and compared across groups with age and sex as covariates in a multivariate analysis of co-variance (MANCOVA). The results demonstrate that group membership alone significantly accounts for 32% of the variation in overall gyrification (F(12, 106) = 1.87, p=.06, η²=0.16; Wilk's lambda = 0.68, p=.04). Follow-up ANCOVAs suggest that individuals who use methamphetamine have higher temporal gyrification than MAP and control participants, although this result was not statistically significant. There was also a significant effect of age on gyrification (F(6, 50) = 5.37, p<.01, η²=0.39; Wilk's lambda = .61, p<.01). Further associations between gyrification and age (r=-0.43, p<0.05), cannabis use and temporal gyrification (r=0.29, p<0.05), alcohol use and temporal (r=0.34, p<0.05) and parietal gyrification were found (r=0.26, p<0.05), as well as age of methamphetamine use onset (r=-0.40, p<0.05). These results offer more evidence on the harmful effects of drug use on brain structure, posing new questions around the developmental basis of gyrification and its status as a biomarker for disease."]},{"key":"dc:title","label":"Title","values":["Cortical Gyrification in Methamphetamine Associated Psychosis: A Potential Neurodevelopmental Biomarker for Risk of Psychosis"]}]}],"canonical_facts":{"dc:contributor.advisor":["Malcolm-Smith, Susan"],"dc:creator":["Gribble, Amy"],"dc:date.accessioned":["2025-02-13T13:13:38Z"],"dc:date.available":["2025-02-13T13:13:38Z"],"dc:date.issued":["2024"],"dc:description.abstract":["For many years, methamphetamine associated psychosis (MAP) has been viewed as a symptomatic, genetic, and morphological blueprint for schizophrenia spectrum disorders (SSD) (Aoki et al., 2013; Grant et al., 2012; Uhlmann et al., 2016; Yang et al., 2021). MAP is currently diagnosed as a substance induced disorder; however, many researchers suggest that MAP may represent a transition into SSD following substance use (McKetin, 2018). The current study investigated global and local gyrification indices (GI) as a potential neurodevelopmental biomarker for psychosis vulnerability in three quasi-experimental groups; methamphetamine users without psychosis (n=21), individuals with MAP (n=18) and healthy controls (n=21). Gyrification indices were determined for each participant using Freesurfer 7.2 and compared across groups with age and sex as covariates in a multivariate analysis of co-variance (MANCOVA). The results demonstrate that group membership alone significantly accounts for 32% of the variation in overall gyrification (F(12, 106) = 1.87, p=.06, η²=0.16; Wilk's lambda = 0.68, p=.04). Follow-up ANCOVAs suggest that individuals who use methamphetamine have higher temporal gyrification than MAP and control participants, although this result was not statistically significant. There was also a significant effect of age on gyrification (F(6, 50) = 5.37, p<.01, η²=0.39; Wilk's lambda = .61, p<.01). Further associations between gyrification and age (r=-0.43, p<0.05), cannabis use and temporal gyrification (r=0.29, p<0.05), alcohol use and temporal (r=0.34, p<0.05) and parietal gyrification were found (r=0.26, p<0.05), as well as age of methamphetamine use onset (r=-0.40, p<0.05). These results offer more evidence on the harmful effects of drug use on brain structure, posing new questions around the developmental basis of gyrification and its status as a biomarker for disease."],"dc:identifier.uri":["http://hdl.handle.net/11427/40951"],"dc:publisher.department":["Department of Psychology"],"dc:publisher.institution":["University of Cape Town"],"dc:subject":["Psychology"],"dc:title":["Cortical Gyrification in Methamphetamine Associated Psychosis: A Potential Neurodevelopmental Biomarker for Risk of Psychosis"],"dc:type":["Thesis / Dissertation"],"dc:type.qualificationlevel":["Masters"]},"updated_at":"2026-07-22T22:23:13Z"}