Genetics can help explain addiction, the genetic explanation of addiction focuses on the fact that an individual may have gene which makes them more susceptible to pursue addictive behaviours e.g. drug taking. The A1 variant of the DRD2 gene has been linked with the initiation addiction. People with the A1 variant are said to have few dopamine receptors as a result Noble refers to the gene as the "reward gene", this is because dopamine is a neurotransmitter which we associate with reward and pleasure. Alcohol/drugs can increase the level of dopamine (this compensates for the lack of dopamine receptors in individuals with A1 variant of the DRD2 gene).
This shows support as a high optimum level of nicotine is needed in order to avoid severe withdrawal symptoms. However one weakness surrounding this area is the issue of reductionism; the model is largely focused on the biological basis of addiction, ignoring social and environmental factors. Another weakness may be deterministic as individuals may have little or no control over their addictive behavior due to biology because some people may be genetically predisposed to their addictive behavior and therefore unable to regulate their behavior. There is also a research on biochemistry of the maintenance of smoking. Research has found that as nicotine increases dopamine release, it tends to provide a pleasurable and rewarding feeling that leads to maintenance.
This is because chronic exposure to the nicotine eventually results in a chronic stress situation for the addict, characterised by withdrawal symptoms. This is effective at explaining why the smoking is maintained because as the withdrawal symptoms affect the user so negatively if the substance is stopped, the addiction is maintained to avoid this negative experience. Similarly the explanation is also as effective at explaining why the addicts relapse after giving up smoking. This is because as the withdrawal symptoms are so hard to resist and lead to such a negative experience, the user eventually takes the substance again to feel better. Also as the user’s brain is expecting a pleasurable experience from the addiction, it creates difficult to resist cues that the addict finds hard to
The two main neurotransmitters found to be linked to aggressive behaviour are serotonin and dopamine. High levels of serotonin are said to reduce aggression by inhibiting responses to emotional stimuli that might otherwise lead to aggressive behaviour. Low levels are associated with an increase in impulsive behaviour, aggression and even violent suicide. Evidence supporting the importance of serotonin in aggressive behaviour was found in research using vervet monkeys. Raleigh et al (1991) found that if serotonin levels were reduced by altering their diet, there was an increase in aggressive behaviour whereas an increase in serotonin levels resulted in a decrease in aggressive behaviour suggesting the difference in aggression was due to the serotonin levels.
Grilly had found people with Parkinson’s disease (low levels of dopamine) who were taking the drug L-dopa to raise their levels of dopamine were developing schizophrenic type symptoms. There is a flaw with one of the key pieces of evidence to support the dopamine hypothesis. The drugs used to treat schizophrenia by blocking the dopamine receptors can actually increases it as neurons struggle to compensate for the sudden deficiency. Haracz, in a review of post-mortem studies of schizophrenics, found that most of those studied who showed elevated dopamine levels had received antipsychotic drugs shortly before death, unlike post-mortem of schizophrenics who hadn’t received medication these results showed that these individuals had normal levels of dopamine. Therefore, this evidence then in fact weakens the support for the dopamine hypothesis.
Impaired judgments due to decreased levels of inhibitions can lead to risky sexual activity. As well, those users that use intravenously increase their chances of contracting HEP B or C or HIV/AIDS. Crystal methamphetamine is not necessarily an aphrodisiac, but through increasing the level of dopamine through triggering the release of powerful brain chemicals, it may increase sex drive. Ironically, while desire and stamina are increased, it ultimately decreases the users’ sexual desirability and performance (PBS, n.d.). 6connected with the fact that crystal meth can suppress one’s appetite.
Methamphetamine or Meth, like other drugs, can short circuit the survival system by artificially stimulating pleasure areas in the brain. As this happens, it leads to increased confidence in meth and decreased confidence in normal everyday life. When this occurs the user becomes more interested in meth related activities, people, and environments. Withdrawals of meth use: fact or fiction? Much to contrary belief meth users do suffer from withdraws as well as any other addict would.
In general, a brain affected by Dementia produces less of some neurotransmitter. which sets off an imbalance in the brain. For Example, In Alzheimer's, Too little Dopamine effects the acetylcholine levels in the body and starts to block receptors , disabling the brain to reach the right signal to the intended brain cell. Amino Acids, Monoamines, Trace amines, Peptides and Gasotransmitters are some of the endogenous chemicals who’s function it is to allow the transmission of signals from one neuron to the next neuron across the synaptic Cleft. Only 100 chemical messengers have been found to date.
It can help mellow them down in social situation and in life in general. However, for someone else suffering from anxiety may be affected differently by the drug. They may feel drowsy, unable to function correctly and don’t really care about themselves and their surroundings. Almost like they are living in a world where it is carefree, they can do whatever they want. The third principle is, the size and quality of the drug’s effect depends on it’s dosage.
Many researchers, such as Crow (1985) believe there are two different types of SZ with different underlying pathology. Type 1 SZ is the type of SZ which would be associated with the Dopamine Hypothesis; it involves DA dysfunction, is characterised by positive symptoms and responds well to anti-psychotic medication. Type 2 SZ, however, is the type that is unsupportive of the Dopamine Hypothesis- it is a neurodevelopmental disorder arising from prenatal insults or perinatal insults, characterised by negative symptoms and does not respond well to antipsychotic drugs. The idea of different types of SZ suggests that DA is not the only