Monday, January 28, 2013

#11 Neurotransmitters



A neuron (nerve cell) is an electrically excitable cell that processes and transmits information through electrical and chemical signals. Neurotransmitters are the brain chemicals that communicate information throughout our brain and body by relaying signals between neurons. The brain uses neurotransmitters to tell your heart to beat, your lungs to breathe and your stomach to digest.  Most importantly for our consideration, they affect mood. They are the parts of the central nervous system most affected by psychoactive drugs and other addictive behaviors like gambling, pornography, binge eating etc. Addiction triggers and magnifies the sensations or feelings that have a natural counterpart (neurotransmitters) in the body.
Dopamine is often known as the reward neurotransmitter as it triggers feelings of pleasure. If something feels good, dopamine is involved. All psychoactive drugs increase the levels of dopamine which is experienced initially as mood elevation and euphoria. Dopamine also helps regulate fine motor muscular activity and blocks pain. For example, it is exciting to win a race but with a stimulant drug like methamphetamine it would be ecstatic or 8 times as pleasurable.  In the early times of the Civil War, drinking alcohol was the only anesthetic for amputations and other painful surgeries. When someone ingests too much alcohol their muscular movements are affected by the flood of dopamine. The neo-cortex and sound judgement gets hijacked and numbed. (see Post #10, Addiction and the Brain)
Norepinephrine and Epinephrine (adrenaline) are strongly associated with bringing our nervous systems into "high alert." They increase our heart rate and our blood pressure. Our adrenal glands naturally release them into the blood stream. Stimulants like methamphetamine trigger these two neurotransmitters as well as dopamine. With large doses of meth, addicts can become so "over alert" they hallucinate visually and hear noises that don't exist. They can exhibit classic symptoms of paranoia. Rapid movements and nonsensical speech are also symptoms. All the basic instincts that reside in the primitive brain are exaggerated (particularly aggression and the sexual drive).
Endorphin is short for endogenous morphine. It is structurally very similar to the opioids (opium, morphine, heroin, oxycontin, codeine, percodan etc.) and works by attaching to the endorphin receptor sites. It creates pain reduction as well as pleasure. Endorphins are produced by the pituitary gland and the hypothalamus which are part of the neo-cortex as opposed to the other potential addictive neurotransmitters being part of the primitive brain. (see Post #10, Addiction and the Brain). This is one reason why it is so difficult to diagnose opiate addiction, as there is little loss of motor control as there is with dopamine (staggering, slurred speech and impaired vision etc.) An exception would be an overdose of opiates characterized by nodding off. Dilation of the pupils is about the only visible symptom, and often opiate abusers wear sun glasses as their visual perceptions appear so bright. 
Serotonin is an inhibitory neurotransmitter that is intimately involved with emotion and mood. Depletion of serotonin is related to depression, problems with anger control, and obsessive-compulsive disorders. Hallucinogens such as LSD, mescaline, psilocybin and ecstasy attach to serotonin receptor sites and block transmissions in perceptual pathways distorting perception of reality. 
Anandamide is has an affinity for receptor sites that accommodate THC (Tetrahydrocannabinol) the main ingredient in marijuana. It is found in the limbic system of the primitive brain and the areas responsible for integration of sensory experiences with emotions.  Long term studies continue to show that marijuana can become addictive and long term use affects learning, motor coordination, and memory.
In summary, drugs and other addictive behaviors imitate the brain's natural chemical messengers and over stimulate the reward circuit of the brain. With our understandable concerns about addiction the rates of addiction must be put in perspective. Addiction takes considerable time to develop. 1% of first-time users of inhalants and tranquilizers were addicted a year later. For hallucinogens and sedatives the figure was 2%, pain relievers and alcohol 3%, powder cocaine 4%, uppers 5%, marijuana 6%, crack cocaine 9%  and the most addictive was heroin at 13%. The greatest predictor of addiction is the age of first use.
Addicts are searching for a means of dealing with psychosocial stress associated with developmental psychological stress and social dislocation. (See blog # 7, Dislocation) The addict is drawn to a culture which promises to complete these unfinished tasks and this influences their drug of choice. Opiate users are drawn to themes of nurturing and support. Stimulant users are drawn to themes of autonomy. Hallucinogen users are drawn to themes of inclusion and belonging. Alcohol users are drawn to themes of will and power. The cultures of technology are sufficiently broad as to offer the psychological rewards of all the cultures of substance abuse combined. Ross Laird.com
My next post will explore the role of willpower in addiction.

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