Hippocampal Association with Brain Electrical Activity in Psychotic Disorder and Healthy Control Subjects with and without Cannabis Use

Walid Yassin, DMSc

Beth Israel Deaconess Medical Center,McLean Hospital – Faculty
Yassine_Walid poster

Scientific Abstract

Background: Our preliminary findings revealed cannabis’s (CA) effect on the hippocampus (HP) as well as psychosis related symptoms and behavior. In the current study, we seek to delineate the effects of CA on the brain in relationship to HP and its associated brain electrical activity in psychotic disorder (Pro) subjects and healthy control (HC). We hypothesize that the alteration of the structure-physiology coupling of HP will be linked to an increase in clinical severity and deterioration of cognition and functioning.

Methods: 1121 Pro and 532 HC were included. The magnetic resonance imaging (MRI), and electrophysiology data were acquired according to the Bipolar-Schizophrenia Network on Intermediate Phenotypes protocol and were processed using a standard pipeline. Statistical analysis used t-test, and Chi-square test to find the differences between the subject groups for the demographic, MRI, electrophysiology, clinical, cognitive, and functional data, as well as recreational CA use (recreational vs. none). Pearson’s Correlation was used to find the association between the HP, and electrophysiology data. Significance set at p<.05.

Results: Significant differences in age, sex, HP, N100, N200, P3a, and Gamma between Pro and HC were observed. There was a noticeable change in Beta and Gamma between Pro+/-. Correlation analyses in HC- and Pro-, showed an association between HP and the brain electrophysiological measures. No associations were found in those who use HC+ or Pro+. The difference between the two correlations in HC+/- and Pro+/- calculated using Fisher r-to-z transformation showed significant change in N200 only. SFS and BACS were significantly different between Pro+/-. The Pro+ group was split into two groups at the median using either the functioning, clinical or cognitive scores. The resulting groups were compared in terms of HP structure-physiology coupling. No differences were observed.

Conclusion: Even though we saw a significant change in the structure- physiology coupling in both HC and Pro before and after CA is used recreationally, especially in N200, this change was not linked to impairment of cognition, functioning or clinical severity.

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research Areas


Walid Yassin, DMSc, MMSc, Elisabetta C. del Re, PhD, David Parker, PhD, Victor Zeng, BS, Sarah Keedy, PhD, Jennifer McDowell, PhD, Elliot Gershon, MD, Godfrey Pearlson, MD, Carol A. Tamminga, MD, Brett A. Clementz, PhD, Matcheri S. Keshavan, MD

Principal Investigator

Walid Yassin, DMSc, MMSc