How Marijuana Affects the Brain

Marijuana has an active ingredient known as THC or delta-9 tetrahydrocannabinol which is a psychoactive cannabinoid compound which produces a euphoric effect impacting the brain by binding with specific cannabinoid receptors that control memory, thought, perceptions of time and depth, as well as coordination of movement. THC also effects production and re-uptake of various neurotransmitters in the brain or central nervous system causing disturbances of the normal signals constituting the limitations on the control of the brain. The chemical slows responses of the neurotransmitters and alters signals between neurons producing a state of relaxation or calmness. Continued interference and altercations to these signals may be a prelude to other mental episodes such as hallucinations, delusions, memory impairments, and disorientation. Long Term abuse may lead to other psychiatric issues such as mental illness, anxiety, depression, and psychosis.

Brain Composition Changes as a Result of Marijuana Abuse

Effects on brain structure due to heavy marijuana use may be subtle but, comparisons of structural differences in MRI images have shown that there is a possible reduction of grey brain matter in these users when compared to non-users. The grey matter of the brain is associated with thought processing, decision making, and ability to evaluate rewards or consequences. In the brain, grey matter makes up the volume of nerve cell bodies as opposed to white brain matter which relates to the connection between the cells. The THC chemical in marijuana alters the way sensory information is processed and interpreted when it attaches to receptors in the hippocampus region of the brain which is responsible for memory function. Activity in these nerve cells decreases with marijuana use and causes structural changes which may damage the cerebral functions of the brain governing emotions and behaviors.

Are the Effects of Marijuana on the Brain Permanent?

There are conflicting results in the study of long term effects of cannabis use on the brain. Imaging studies show consistent alterations in brain tissue composition, but more research is needed to determine permanently impaired cognitive functions. Marijuana users are subject to permanent brain effects when the cannabinoid receptors are repeatedly altered. Nerve cell damage can impair mental abilities and functions which may lead to further mental health issues. Resulting reactions or responses may increase the possibility of dual addictions, for which, marijuana is commonly referred to as a “gateway” drug.