Functional connectivity alterations in brain networks relevant to self-awareness in chronic cannabis users

• Published in: Journal of psychiatric research 2014-04, Vol.51, p.68-78
• Main Authors: Pujol, Jesus, Blanco-Hinojo, Laura, Batalla, Albert, López-Solà, Marina, Harrison, Ben J, Soriano-Mas, Carles, Crippa, Jose A, Fagundo, Ana B, Deus, Joan, de la Torre, Rafael, Nogué, Santiago, Farré, Magí, Torrens, Marta, Martín-Santos, Rocío
• Format: Article
• Language: English
• Subjects: Anxiety; Anxiety - etiology; Awareness - physiology; Biological and medical sciences; Brain; Brain - blood supply; Brain - pathology; Brain Mapping; Cannabis; Female; fMRI; Functional connectivity; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Marijuana Abuse - complications; Marijuana Abuse - pathology; Marijuana Abuse - psychology; Medical sciences; Memory; Memory Disorders - etiology; Neural Pathways - blood supply; Neural Pathways - pathology; Neuropsychological Tests; Oxygen - blood; Psychiatric Status Rating Scales; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Resting state; Self-awareness; Selfawareness; Young Adult
• ISSN: 0022-3956; 1879-1379
• DOI: 10.1016/j.jpsychires.2013.12.008

Abstract Background Recreational drugs are generally used to intentionally alter conscious experience. Long-lasting cannabis users frequently seek this effect as a means to relieve negative affect states. As with conventional anxiolytic drugs, however, changes in subjective feelings may be associated with memory impairment. We have tested whether the use of cannabis, as a psychoactive compound, is associated with alterations in spontaneous activity in brain networks relevant to self-awareness, and whether such potential changes are related to perceived anxiety and memory performance. Methods Functional connectivity was assessed in the Default and Insula networks during resting state using fMRI in 28 heavy cannabis users and 29 control subjects. Imaging assessments were conducted during cannabis use in the unintoxicated state and repeated after one month of controlled abstinence. Results Cannabis users showed increased functional connectivity in the core of the Default and Insula networks and selective enhancement of functional anticorrelation between both. Reduced functional connectivity was observed in areas overlapping with other brain networks. Observed alterations were associated with behavioral measurements in a direction suggesting anxiety score reduction and interference with memory performance. Alterations were also related to the amount of cannabis used and partially persisted after one month of abstinence. Conclusions Chronic cannabis use was associated with significant effects on the tuning and coupling of brain networks relevant to self-awareness, which in turn are integrated into brain systems supporting the storage of personal experience and motivated behavior. The results suggest potential mechanisms for recreational drugs to interfere with higher-order network interactions generating conscious experience.