Over the past few decades, we’ve learned that some parts of the human brain continue to develop until at least the age of 25 in women and 28 in men. Heavy exposure to marijuana before this age can negatively impact brain development, resulting in damage affecting many bodily and mental functions.
By coincidence, THC, the main intoxicant in marijuana, chemically resembles the human neurotransmitter anandamide, which is a substance our bodies use to relay instructions to nerve and brain cells (neurons). Anandamide helps control memory, brain growth, bodily growth, sleep, attention, learning, impulsivity, mood, IQ, and executive function – basically, the control room of the brain. Sadly, THC molecules partially mirror anandamide and can “trick” the brain into allowing it to fit into and block the receptor sites in neurons specifically intended for endocannabinoids. This overstimulates the receptor and prevents these natural chemicals from doing their jobs.
If this happens too often, the invasive THC short-circuits the brain’s normal neural connections, especially in the frontal lobe and hippocampus (where all the above brain functions live), causing brain changes. This can lower your overall intelligence and cause depression, as well as impact your ability to sleep well, pay attention, store memory, and control impulses. Damaged executive function may produce effects like those suffered by individuals with traumatic brain injury or autism: lack of empathy, inability to follow basic procedures, loss of motivation, and poor short-term memory.
Some of the effects of marijuana poisoning have proven long-term or permanent, including drops in IQ. But the brain has great neuroplasticity when young, so some can be overcome or improved if usage stops completely. It’s never “too late” to quit!