Brain Chemistry of Addiction

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By: Michael Stone, MD, Addiction Medicine Specialist,
Director, Cornerstone of Southern California

Thank you for coming to this site and taking the time to read my article. Unfortunately I have some bad news. People die from addiction every day. It is a progressive, debilitating and potentially fatal brain disease that continually reminds us all that addiction is a major killer and destroyer of lives. Even with all of our knowledge and work, it is still an uphill battle. Once you know of this disease being present it deserves all your energy and the help of your support system to fight it.

So many people in the addict's support system continue to tell me that the problem is the addict's, not theirs. NOT TRUE!! This is a fatal disease - everyone needs to get involved to the maximum - no excuses. Being sorry, as the coffin is lowered into the ground or the ashes are scattered about, is too late to wish you had been more involved. If we are to help save a life, we all have to be involved in treatment and training. Parents, spouses and others in the addict's support system cannot be too busy to be educated or involved in the addict's recovery. Denial of the disease and isolation from the addict is not an acceptable solution.

I will now turn my discussion to the brain chemistry of addiction. I will use cocaine as my example. When you take cocaine it completely dissolves into the body's water and spreads to every part of the body. Remember that your body is about 87% water. It has many effects on your body, but the important one for addicts is in the "feeling center." Here it causes an increase in the level of dopamine and to some extent nor-epinephrine, which leads to the receptors in your brain getting a lot of hits. The end result is that there is a lot of stimulation from the increase in dopamine and no-epinephrine. The person feels this as being energized, feeling "good", "stimulated", and "high". The more cocaine is used the more dopamine, et al, is used up and the more receptors get hit. This leads to depletion of total dopamine so when you stop the use of cocaine you have a deficiency of dopamine for a few days to a few weeks causing symptoms of withdrawal, depression, tiredness, hunger, and irritability. These symptoms subside and all returns to normal in a few weeks with rest, sleep, and a proper diet.

The second problem from using cocaine over a few days is that the receptors get hit a lot and after a while respond by protecting themselves. This leads the receptors to build a shield against the effect of dopamine requiring the person to use more and more cocaine in an effort to get back to the same high.

Cocaine causes its effect by increasing the availability of your body's own natural dopamine. Heroin or Vicodin (opiates) on the other hand directly hit the opiate receptors. Opiates taken into your body bypass your body's natural opiate system that uses endorphins and enkephalins as neurotransmitters. These enkephalins act as chemical messengers between two or more cells in your brain. Because the heroin/Vicodin bypasses the natural opiates in your body, after a while your body cuts back on producing its own natural endorphins/enkephalins when heroin is used daily. As these receptors receive constant hits from the continued use of heroin it causes them to

become less sensitive and the addict needs to increase the dose of heroin/Vicodin to get the same effect.

When the drug use is stopped there is a withdrawal syndrome as the receptors get back to normal and the natural endorphins/enkephalins return to their normal level. Again it takes food, rest, and time. Methamphetamine works on the "feeling center" using the neurotransmitter nor-epinephrine causing stimulation. Barbiturates (Phenobarbital, etc.) and benzodiazepines (Valium, Librium, Klonopin, Xanax, Ativan, and Serax) work on the G.A.B.A. (gaba amino butyric acid) neurotransmitter system causing tranquilization, sedation, and sleep.

Marijuana probably works on the cannabinoid system causing hallucinogenic/perceptual effects. Alcohol works as a drug on your brain as well as a toxic cell poison on the rest of your body, causing stimulation in low dosage, sedation and pain relief in moderate dosage, and perceptual effects in high dose (drunkenness). Nicotine acts as a stimulant working on the acetyl choline system, with effects similar to cocaine and/or methamphetamine. Caffeine works on the dopamine and nor-epinephrine system.

This has been a simplified explanation of the direct effects of certain chemicals (drugs) which come into the body, get to the "feeling center," and cause a person to get high by affecting the neurotransmitter system in that part of the brain. This is a brain disease. My next article will discuss how certain behaviors as opposed to actual drugs can be addicting.

MICHAEL STONE, MD, Addiction Medicine Specialist
Cornerstone of Southern California

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