The other major neurotransmitter, dopamine, controls movement and posture. The loss of dopamine in certain parts of the brain causes muscle rigidity, a symptom typical of Parkinson’s disease. The effect of dopamine mirrors that of adrenalin – its release causes the user to experience increased emotional response and so they are more able to experience positive feelings such as pleasure and content.
Cannaboids act in a very similar way to dopamine and are found in a variety of things (there are even small amounts in chocolate!) They have effects similar to those of a general anaesthetic – numbing of pain and a general feeling of calmness. In marijuana alone, there are 80 different types of cannabiniods. Marijuana has been found to help people with Dystonia Disorder, Huntington’s Disease, Epilepsy, Tourette Syndrome, Dyskinetic Syndrome, the after effects of a Stroke, and Psychotic Activity by mimmicing the act of anandamide, a naturally occuring chemical in the body.
Sufferers rely on mariujana because it’s pain relieving effect is much stronger than that of anandamide. Maijuana does affect behaviour, some users can get bad effects from it – they may suffer sudden feelings of anxiety and have paranoid thoughts. This is more likely to happen when a more potent variety of marijuana is used as the effect of marijuana does have a great deal to do with how strong it is, i.e., how much of the active chemical of THC is in it.
Along the lines of smoking, nicotine is one of the most abused drugs in the world. When a cigarette is smoked, nicotine, the main psychoactive ingredient contained in tobacco, (along with many other chemicals such as carbon monoxide) is absorbed through the lungs. In the early 1990’s, Pomerleau and Pomerleau found that the nicotine contained in the tobacco causes the release of serotonin, beta-endorphin and growth hormone, which are all well-known behaviour modifiers. Nicotine receptor sites, located in the peripheral nervous system, are the neuromuscular junctions of voluntary muscles.
As nicotine enters the body, these receptors are stimulated and the smoker is likely to experience muscular tremors. Other ways in which nicotine changes behaviour include an increased heart rate and a higher blood pressure. Also, vasoconstriction of the blood vessels causes lower body temperature, thus explaining the cold touch smokers seem to have and why they tend to age faster. Smoking also has positive effects on mood as the smoker uses nicotine to control their response to stress. The release of epinephrine arouses the sympathetic system yet most smokers report that they smoke because it relaxes them. Despite this, a survey carried out in the UK by West (1993) found that smokers have lower levels of psychological well-being than non smokers and ex-smokers.
Another commonly used drug is alcohol. Alcohol has a depressant effect on the central nervous system, (including the brain and the nerves that control muscle action). When alcohol first enters the body, people experience an initial sense of well-being and relaxation. The impairing effects of alcohol are realised when the user is unable concentrate on complicated tasks demanding quick choices and accurate responses. After a few drinks, the rate at which information is processed slows down. The ability to concentrate on a task or to divide attention between tasks decreases. Brain functions are reduced and after too many drinks, judgment, emotions and also behaviour are affected.
The more alcohol consumed, the greater the effects. Problems with muscular coordination will arise, slurring of words, losing balance and generally having slower reaction times are all typical examples of drunken behaviour. Emotional outbursts might express strong feelings of sadness or hostility. Aggressive behaviour can become a problem because when a person is drunk; their inhibitions are lowered and feel much more free to express their true opinions.
Recent research (August 2004) conducted by Sir Michael Marmot of the University College of London suggests alcohol (in moderation) actually sharpens the brain. 6000 civil servants were asked to complete a psychometric test where the questions asked included verbal and mathematical reasoning problems and tests of short-term memory. The participants’ performance was then matched against their drinking habits. The results were surprising – those who had had as little as one unit of alcohol scored higher than those who had had none whatsoever. In fact, teetotalers were more likely to achieve a lower score than occasional drinkers.
“Our results appear to suggest some specificity in the association between alcohol consumption and cognitive ability,” said the team. “Frequent drinking may be more beneficial than drinking only on special occasions.” Also in support of moderate drinking, a recent study conducted in America suggested that drinkers suffered significantly less cognitive decline with age than teetotalers. Perhaps alcohol is able to slow the decline of mental function as we get older.
On the other hand, alcohol abuse can lead to so many problems. People don’t realize how many calories alcohol contain, too much can lead to rapid weight gain. Long term abuse of alcohol has also led to reduction of brain mass, i.e., brain cells literally being killed off. Because alcohol affects emotional centers in the limbic system, alcoholics also become anxious, depressed and in extreme cases, even suicidal. The emotional and physical effects of alcohol can contribute to marital and family problems, including domestic violence, as well as work-related problems, such as excessive absences and poor performance
Cocaine is another widely abused drug – it is an agonistic (it enhances the neurotransmitter dopamine’s effect by copying its’ action.). The effects of this drug are extremely harmful to the body and the cost related to cocaine can include lead to permanent damage, addiction and even death. While individual user of the drug will react differently, effects of the drug can fall into two categories: short-term effects and long-term. Even if a person has only used cocaine once, they will experience short-term side effects. Long-term effects only appear after increased periods of use and are dependent upon both the duration of usage and amount consumed.
Short term effects include increased blood pressure, vasoconstriction of the blood vessels, increased energy heart rate, decreased appetite and an increased temperature. Long term effects include addiction, paranoia, irritability, restlessness, auditory hallucinations (hearing voices) and mood disturbances. Researchers have reported that as much as 50 percent of the dopamine-producing cells in the brain can be damaged after prolonged exposure to relatively low levels of cocaine. Researchers also have found that serotonin-containing nerve cells may be damaged even more extensively. This toxicity is bound to be related to the psychosis seen in some long-term drug abusers