Effects of Marijuana Use on Brain Structure and Function: Neuroimaging Findings from a Neurodevelopmental Perspective

Abstract

Marijuana, behind only tobacco and alcohol, is the most popular recreational drug in America with prevalence rates of use rising over the past decade. A wide range of research has highlighted neurocognitive deficits associated with marijuana use, particularly when initiated during childhood or adolescence. Neuroimaging, describing alterations to brain structure and function, has begun to provide a picture of possible mechanisms associated with the deleterious effects of marijuana use. This chapter provides a neurodevelopmental framework from which recent data on brain structural and functional abnormalities associated with marijuana use is reviewed. Based on the current data, we provide aims for future studies to more clearly delineate the effects of marijuana on the developing brain and to define underlying mechanisms of the potential long-term negative consequences of marijuana use.

Keywords: Adolescence; Cannabis; Endocannabinoids; Marijuana; Neurodevelopment.

Fig. 1

Weighted color maps. (A) Neuroanatomical alterations in marijuana users (blue (dark gray in the print version)–green (light gray in the print version)), relative to control subjects. (B) Brain map with regional distribution of cannabinoid receptor density [dark green (dark gray in the print version)–light green (light gray in the print version); range, 40–1680 density of receptor binding sites, measured via autoradiographic techniques (3)]. Lighter colors indicate evidence from more studies and greater density of receptors. (C) Binary map (red (gray in the print version)) illustrates overlap between (A) and (B), including regions high in cannabinoid receptors that also show neuroanatomical alterations. (D) Binary map (violet (light gray in the print version)) illustrates nonoverlap between (A) and (B), including areas that showed neuroanatomic alterations and are low in cannabinoid receptors. Used with permission from Lorenzetti, V., Solowij, N., & Yücel, M. (2016). The role of cannabinoids on neuroanatomical alterations in cannabis users. Biological Psychiatry, 79, e17–e31. doi:10.1016/j.biopsych.2015.11.013.