Neuropsychopharmacology is an area of scientific study which investigates the effect of drugs on the nervous system and behaviour. One drug in particular has attracted profound interest and research. Alcohol was discovered accidentally in the prehistoric times and a strong concentration of it was first found in Arab, where it’s named originates from, ‘alkuhl’ (Arabic word) (Rouechï¿½, 1966; as cited in Feldman, Meyer ; Quenzer, 1997). The pleasurable effects of alcohol have since been increasingly enjoyed by most societies.
Although laws on amount of consumption (for driving) and age limits have been put into place in the majority societies, the recently reported binge drinking culture in youths today is becoming a cause for concern and research into alcohol effects is a talked about topic of the moment. This essay will be discussing weather humans should drink alcohol by considering the positive and negative effects of alcohol with reference to biological explanations and evidence. As it will be seen, the answer to this isn’t as straight forward as it may first seem.
Alcohol is a depressant that affects the central nervous system (CNS). Excessive amounts enhances activates of the neurotransmitter GABA in the brain, which cause unwanted behaviours and motor coordination problems (Hanchar, Dodson, Olsen, Otis & Wallner, 2005). On the other hand, moderate amounts slows down the actions of the sympathetic nervous system and activates neural firing which make drinkers feel relaxed and confident in social situations.
Leifman et al. (1995; as cited in Pitts & Phillips, 1998) reported better social skills in moderate drinkers compared to high or non drinkers. Alcohol can also act like a sedative by enhancing the activities of the neurotransmitter GABA which causes drinkers to feel less anxious. Other neurotransmitters are also affected such as serotonin levels get lower (Fil-Aime el al., 1996), dopamine levels increase which makes drinkers feel cheerful and confident and endogenous opioid are activated which are the bodies natural pain killers. Such positive factors may encourage repeated drinking in moderate amounts. (Di Chiara, Acquas & Tanda, 1996; De Witte, 1996). However, alcohol abuse can have many negative effects.
The main negative effect of alcohol abuse is brain damage. Purkinje cells in the cerebellum, hippocampus, the cells of the frontal cortex and hippocampal pyramidal are well known areas to be affected and damage to these areas could impair cognitive functions. Crews and Nixon (2002) found that alcohol prevented new neurons forming in the hippocampus of rats, which affected their cognitive abilities. In another study on rats by Crews, Obernier, White and Swartzwelder (2002) found that cognitive abilities are affected when the parts connected to the hippocampus are impaired such as the limbic structures and the olfactory bulbs which are related to spatial learning abilities.
However, it must be questioned weather animal findings are applicable to humans. Brain damage also has an impact brain size. Alcoholic’s brains are distinctively smaller than brains of non-alcoholic (Kril, Halliday, Svoboda and Cartwright,1997) due to the loss of white matter in the brain rather than grey (Harper and kril, 1991). However, despite such serious and tragic impact of alcohol abuse, it has been discovered that some parts of brain damage are reversible and cognitive abilities can be improve if alcoholics stop drinking (Bartsch et al, 2007; Carlen and Wilkinson, 1987). Brain damage can also cause dementia known as Korsakoff’s syndrome.
Korsakoff’s syndrome affects the memory system and caused by Vitamin B1 (thiamine) deficiency which is essential for the brain to function. Mair, Warrington and Weiskrantz (1979) evaluated longitudinal case studies on two Korsakoff’s syndrome patients and reported that both had cognitive damage which caused long-term and short-term memory problems, brain shrinkage and unhealthy mammillary bodies. Visser et al. (1999) later added that memory loss in Korsakoff’s syndrome was due to the deterioration of the nuclei in the midline thalamus. An analysis of a number of studies also established that Korsakoff’s syndrome is caused by impaired neurons in the cortical and sub cortical areas of the brain (Harper and Kril, 1994). However, it can be argued that Korsakoff’s syndrome maybe due to alcoholic’s poor diet, rather than the alcohol alone. Another condition of brain damage is caused by prenatal alcohol exposure.
Alcohol consumption by pregnant women can affect pregnancy and fetus development. Placental problems can occur where blood flow in the umbilical cord is restricted, preventing oxygen and nutrients getting to the fetus and effecting development. In cases where women are lucky enough to have no placental problems, they may give birth to a child with Fetal Alcohol Syndrome (FAS); around 40% of women who drink alcohol during pregnancy give birth to children with FAS (Abel, 1984, Colangelo and Jones, 1982, as cited in Rosenzweig, Breedlove & Watson, 2007). The main characteristics associated with FAS are growth and mental retardation due to impact on brain, central nervous system problems and facial defects such as broad nasal bridge, thin upper lip and grove between upper lip and nose (O’Learly, 2004).
The areas of the brain most likely to be affected are the hippocampus, neocortex and cerebellum which have been linked to behavioural problems (Guerri, 2002). Reduction in brain size and neurobehavioral problems can also occur due to disruptions in neural activities of the brain which changes glutamate and GABA activities and results in the death of many nerve cells (Farber and Olney, 2003).
Brain damage in FAS can also lead to impaired cognitive abilities and behavioural problems as Nanson and Hiscock (1990) found, children with FAS were intellectually weaker than normal children and had similar behavioural problems to ADD children. In some cases alcoholic mothers give birth to babies without physical appearance of FAS but still showed other associated problems as reported by Matton, Riley, Gramling, Jones and Delis (1997, 1998), which compared children with FAS to PEA group (children born to alcoholic mothers but not diagnosed with FAS) and found that both children performed poorly on verbal learning, memory, language, motor skills and IQ tests compared to normal children.
Alcohol can have negative affected organs. The liver is affected by a poisonous substance called acetaldehyde which is produced during the chemical breakdown of alcohol by enzymes in the liver. Normally the acetaldehyde is converted into a form of energy called acetic acid, but if excessively amounts remain in the liver it can lead to alcohol hepatitis and cirrhosis.
An unhealthy liver can lead to toxic substances remaining in blood which damages other organs, particularly the brain. Other organs affected are the kidneys, where alcohol acts as a diuretic which increases urine excretion and the heart by affecting the mitochondria which weakens energy metabolism and respiration in the hearts muscle cells. Drinking alcohol also increases chances of getting cancers such as esophagus, liver, mouth, oropharynx, stomach, throat, tongue and breast cancer. Noble (1984, as cited in Feldman et al, 1997) found a higher risk of developing cancer in those who consumed large amounts of alcohol and smoked. However, other factors must be considered.
Genetics has been associated as a risk factor. Evidence shows that alcoholics are likely to have biological relatives who have drinking or substance abuse problems. An adoption study by Cadoret, Chain and Grove (1980) found that adopted children with biological alcoholic parents were likely to become alcoholics. Similar findings were also found by Sigvardsson, Bohman and Cloninger (1996) in a replication study of ‘Stockholm adoption study of alcoholism’ which found that adopted boys were likely to become alcoholics if biological parents were.
However, moderate drinking can have many health benefits. Wine has been associated with prevention of coronary heart disease (CHD), especially red wine (Klatsky, 2007). A study by Jensen, Retterstol, Sandset, Godal and Skionsberg (2006) showed that red wine reduced risk factors associated with coronary heart disease such as plasma viscosity and fibrinogen levels. These protections are due to the biochemical and molecular reactions to resveratrol and quercetin compounds found red and white wine (Providï¿½ncia, 2006).
In summery, alcohol is a depressant that affects the central nervous system. Moderate amounts can make drinker confident and relaxed in social situations but excessive amounts can have undesired effects such as inappropriate behaviour and the feeling of being out of control. Alcohol also alters mood by effecting neurotransmitters GABA, dopamine, serotonin and endogenous opioid. Alcohol abuse can have many negative effects; in particular it can damage the brain and affect cognitive abilities. Brain damage can also cause dementia known as Korsakoff’s syndrome, were memory and cognitive abilities are impaired due to damage in certain parts of the brain. Fetal Alcohol Syndrome (FAS) is also another condition caused by brain damage due to prenatal alcohol exposure. FAS children have a number of distinct characteristics different from normal children and even children born without FAS to alcoholic mothers have other similar characteristics as FAS children.
Apart from the brain other organs can also be damaged by alcohol such as the liver, kidneys and the heart. And chances of getting cancer are also increases with excessive alcohol consumption. Another interesting factor to consider is genetic risk factors for alcoholism as evidence has shown children of alcoholics are more likely to become alcoholics. However, there is same good news; alcohol (especially red wine) can have beneficial effects on health by preventing coronary heart disease. Therefore, alcohol can have some positive effects with moderate intake and negative effects with excessive intake. But perhaps more research is needed in this are before answering a straight yes or no to weather humans should drink alcohol.
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