Discriminative Properties of Hippocampal Hypoperfusion in Marijuana Users Compared to Healthy Controls: Implications for Marijuana Administration in Alzheimer’s Dementia
Affiliations: [a] Amen Clinics Inc. Costa Mesa, CA, USA
| [b]
University of California San Francisco, San Francisco, CA, USA
| [c]
Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA
| [d] UCLA Medical Center, Los Angeles, CA, USA
Correspondence:
[*]
Correspondence to: Daniel G. Amen, MD, Amen Clinics Inc., Costa Mesa, CA, USA. Tel.: +1 949 266 3700; Fax: +1 949 266 3750; E-mail: daniel@amenclinics.com.
Abstract: Background: Few studies have evaluated the impact of marijuana use on regional cerebral blood flow. Objective: To determine whether perfusion in specific brain regions on functional neuroimaging, including those affected by Alzheimer’s disease pathology, are abnormal in marijuana users compared to controls. Method: Persons with a diagnosis of cannabis use disorder by DSM-IV and DSM-V criteria (n = 982) were compared to controls (n = 92) with perfusion neuroimaging with SPECT at rest and at a concentration task. Perfusion estimates were quantified using a standard atlas. Cerebral perfusion differences were calculated using one-way ANOVA. Diagnostic separation was determined with discriminant analysis of all subjects. Feature selection with a minimum redundancy maximum relevancy (mRMR) identified predictive regions in a subset of marijuana users (n = 436) with reduced psychiatric co-morbidities. Results: Marijuana users showed lower cerebral perfusion on average (p < 0.05). Discriminant analysis distinguished marijuana users from controls with correct classification of 96% and leave one out cross-validation of 92%. With concentration SPECT regions, there was correct classification of 95% with a leave-one-out cross validation of 90%. AUC analysis for concentration SPECT regions showed 95% accuracy, 90% sensitivity, and 83% specificity. The mRMR analysis showed right hippocampal hypoperfusion on concentration SPECT imaging was the most predictive in separating marijuana subjects from controls. Conclusion: Multiple brain regions show low perfusion on SPECT in marijuana users. The most predictive region distinguishing marijuana users from healthy controls, the hippocampus, is a key target of Alzheimer’s disease pathology. This study raises the possibility of deleterious brain effects of marijuana use.
