How Cannabis Affects Your Brain
I’m sure you’ve heard—or been told—that cannabis causes memory problems, or brain damage, or some variation of that same theme. But is it true? While the common assumption since the vilification of cannabis started has been that smoking marijuana causes long-term brain damage, recent research has shown the opposite to be true. Scientists have found that although THC can cause some short-term memory problem, cannabinoids in general work as neuroprotectants and actually reduce the risk and effects of conditions characterized by brain or nerve damage. The endocannabinoid system’s main purpose is to modulate other body systems, helping to maintain the body’s natural homeostasis. By regulating the production and transmission of various neurotransmitters such as glutamate and dopamine, cannabinoids can help create balance in a few different ways. This is why cannabis use is beneficial in the treatment of neurodegenerative diseases like ALS and Alzheimers or TBI (traumatic brain injury).
Endogenous cannabinoid receptors (CB1 receptors) are found throughout the CNS, with particularly high concentrations in the cerebellum and basal ganglia (two areas primarily associated with motor function, cognition, and emotion), as well as in the hippocampus (associated with memory and learning). Receptors in the hippocampus explain the short-term memory loss suffered by some smokers, but although some studies report altered hippocampal structure and function in people who began using cannabis during adolescence it is widely agreed that cannabis causes little to know long-term damage. Additionally, even though there might be some negative effects on short-term memory, it seems that other hippocampal actions (such as executive functioning and processing speed) are largely unaffected. (There are markedly low concentrations found in the brainstem, which is why cannabis has such low toxicity).
One of the main causes of nerve damage in neurodegenerative diseases like ALS, MS, and dementia is excitotoxicity, a state in which nerve cells are overstimulated by neurotransmitters—primarily glutamate. Another common cause is overproduction of free radicals which then cause oxidative stress. Because cannabis both modulates the release of neurotransmitters and has strong anti-oxidant properties it logically follows that cannabis can prevent nerve damage and help treat neurodegenerative disorders.
Because THC and other cannabinoids—CBD being a great example—also affect areas that control mood and memory, cannabis also holds great promise as a treatment for certain psychiatric disorders such as PTSD and depression. Many have found relief from symptoms such as hypervigilance and difficulty falling and/or staying asleep, particularly in patients suffering from PTSD. There are more risks associated with cannabis use in patients with psychiatric illnesses, however, than with illnesses that affect other body systems. Several studies have found linkages between cannabis use and psychotic disorders like Schizophrenia, Schizo-affective disorder, or Bipolar mania with psychotic features. It is unclear whether cannabinoids cause these symptoms or if they provoke them only in patients that are already genetically, anatomically, or physiologically predisposed. These negative responses seem to be more prevalent in individuals that begin using cannabis during adolescence. Also keep in mind that cannabis is a depressant and—like other depressants—can make worsen symptoms of depression, and, even though there is virtually no evidence of cannabis being physically addictive, patients with addiction disorders or who are predisposed to addictive behaviors (like some bipolar patients) have a higher risk of psychological addiction.
So if you’re considering trying cannabis as medicine, but are concerned about memory loss or other brain damage, have no fear. Not only does cannabis not kill brain cells, it protects them!