Daria Gramenitskaya

I hold a BSc in Biomedical Science from Imperial College London, and I have just completed an MRes in Experimental Neuroscience at the same university. I became interested in addiction biology, which motivated me to join the Division of Psychiatry for my MRes rotation to study structural changes in substance addiction under the supervision of Dr Louise Paterson, Dr Leon Fonville and Professor Anne Lingford-Hughes.

The presented findings are based on the structural MRI data collected as part of the Imperial College Cambridge Manchester (ICCAM) platform study, which was set up to provide a better understanding of the mechanisms underlying abstinence and relapse.

Cortical thickness abnormalities in abstinent substance-dependent individuals

*Aims* Substance dependence is associated with altered cortical gray matter. We aimed to identify cortical thickness alterations which are shared among alcohol, stimulant and opiate dependencies and those associated specifically with alcohol dependence and investigate their relationship with alcohol exposure and abstinence length.

*Methods* Cortical thickness was measured in abstinent substance-dependent individuals and non-dependent controls using high-resolution T1-weighted scans. Using vertex-wise whole-brain analysis in FreeSurfer we compared cortical thickness between (i) individuals dependent on alcohol, stimulants or opiates (DEP, n=84) and matched controls (n=56), (ii) alcohol-dependent individuals (AD, n=60) and matched controls (n=59) and (iii) alcohol-dependent individuals with co-dependence on stimulants/opiates (ALC+, n=32) and alcohol-only group (ALC, n=28).

*Results* Cortical thickness was significantly decreased in left precuneus, right fusiform and parahippocampal gyri in the AD compared to controls, which was associated with alcohol exposure in ALC but not ALC+ individuals. We found no significant differences in cortical thickness between ALC+ and ALC groups but observed a positive trend between cortical thickness in precuneus and abstinence length in the ALC group and a significant negative correlation between these variables in the ALC+ group. Finally, we observed no differences between control and DEP groups.

*Conclusions* We found no evidence of shared cortical abnormalities in different dependencies. We observed cortical thinning in alcohol dependence in accordance with previous literature, which may be reflected by altered cognitive and behavioural function. Cortical thickness in alcohol-polysubstance dependence and alcohol-only dependence may be distinctly affected by drug exposure and abstinence, which may have implications for treatment outcome.

Poster link: Cortical thickness abnormalities in abstinent substance-dependent individuals