The Brain Chemistry Behind Tolerance and Withdrawal - USDTL
The Center for Disease Control and Prevention defines substance use disorders (SUDs) as ‘treatable, chronic diseases characterized by a problematic pattern of use of a substance or substances leading to impairments in health, social function, and control over substance use’1. Addiction at times can be incorrectly thought of as ‘a moral failing instead of what we know it to be: a chronic treatable brain disease’2, which results in the body sending signals in the absence of the drug. These signals cause the user to ‘crave’ the substance, much like the body sends signals when we are hungry or tired. These physiological changes are related to our body’s natural messengers, neurotransmitters.
Neurotransmitters are the body’s natural chemical messengers that control bodily functions such as breathing, heartbeat and blood pressure, muscle movement, sleep, digestion, and thoughts and memories3. Some examples of neurotransmitters are dopamine, glutamate, serotonin, norepinephrine, GABA, epinephrine, and histamine. The volume and storage of neurotransmitters within the body is highly regulated. The body can sense when there is too little or too much of a neurotransmitter and responds by creating more or destroying the neurotransmitter. Any change of this homeostasis can have severe consequences on the body’s ability to react to external stimuli and can be referred to as intoxication4.
The effects experienced by drugs is related to neurotransmitters. Neurotransmitters work on the body by binding to receptors. Neurotransmitters and their receptors work very similarly to a lock and key. The neurotransmitter perfectly fits into a specific receptor just like a key fits into a specific lock.
