¶ … journal articles web sites. Schizophrenia and bipolar are common mental disorders that make the lifespan of persons with the disorders shorter than the general population. Substance use disorder is a common comorbidity in these individuals. Supporting data from several studies shows that the smoking rates among schizophrenics and bipolar are two to three times those of the general population. It is hypothesized that this is as a result of schizophrenics and individuals with bipolar having the perception that smoking reduces the severity of their symptoms and leads to a better quality of life. This has, however, not been proven through research. Findings from current literature also suggest that smoking among schizophrenics and individuals with bipolar may be related to the N43A gene which has several polymorphisms. By looking at the current research findings from peer reviewed journals, the gap in literature is identified which is then used to describe implications for the future and to give a personal commentary on the topic.

Schizophrenia, Bipolar, and Tobacco Use

Schizophrenia is a chronic mental disease which affects approximately 1% of the world's population. According to the World Health Organization (WHO), it is more common in the younger generation between 20 and 45 years of age than those older than this age. The WHO categorizes schizophrenia as one of the seven diseases that disable people between the ages of 20 and 45. According to his classification, schizophrenia surpasses HIV, diabetes and cardiovascular disease Leucht, Burkard, Henderson, Maj, & Sartorius, 2007.

As a result of this disorder, the individual becomes unable to tell the difference between reality and fantasy which makes them unable to make clear and well directed decisions or to have normal emotional responses

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(Johnson et al., 2010)

. The individuals also become unable to act in a normal way when in social situations. A common fete in schizophrenics that has been noted over the years is suicide. Several reviews that have been conducted have pointed at the excess mortality in schizophrenics which is twice as high as the general population suggesting that schizophrenia is a 'life-shortening' disease Kotov, Guey, Bromet, & Schwartz, 2010()

Bipolar refers to a mental disorder characterized by intervals or extremely good and bad behavior including moods and depression. It is more commonly referred to as 'mood swings' disorder and it affects both women and men equally. It is more common in younger individuals at the age of 15 to about 25 years of age but it may also occur in older individuals. Persons with this disorder experience several symptoms including poor judgment, high tempers and reckless behavior characterized by a lack of self-control, elevated moods leading to hyperactivity, high self-esteem, increased energy or easy agitation.

Comorbidity refers to the situation where two or more diseases or disorders are present in an individual at the same time. The two diseases may occur dependently or independently. Comorbidity of mental disorders alongside disorders of substance abuse is extremely common. This is usually associated with the poor outcomes of treatment of these two disorders as well as severe course of the illness. As a result of this, it becomes extremely difficult to identify, prevent and manage those who have comorbid disorders and has led to increased interest by researchers and policy makers to attempt to understand what can be done to deliver services that reduce these comorbidities at both individual and community level.

Ever smoking from an epidemiological definition refers to a person who has smoked more than 100 cigarettes in their lifetime. From a clinical perspective, it refers to a person who has smoked daily for some period of their life. Current smokers from an epidemiological perspective are those who smoke daily or on particular days. The clinical definition is narrower and states that daily smokers are only those who currently smoke on a daily basis. Smoking cessation from an epidemiological perspective is a person who has ever smoked but is not a current smoker. From a clinical perspective, this refers to someone who has stopped smoking daily. In this paper, the epidemiological definitions are used as result of their broad nature. Tobacco use is defined as the use of any tobacco products including cigarettes, snuff or chewed tobacco, cigars, pipes, etc.

Current research findings

The U.S. ECA (Epidemiological Catchment Area) study conducted on 20,000 respondents was the first study to ever establish the presence of comorbidity of mental disorders with drug abuse disorders. The study found that the most significant drug disorder was with tobacco. The highest comorbidity was found in patients...

Another study was conducted in the early 1990s known as the NCS (National Comorbidity Survey) which examined the extent of comorbidity of severe mental illnesses with substance use and abuse and found similar results to those of the previous ECA study. These two studies led to the development of the hypothesis that there was a relationship between severe mental illnesses and substance use disorders in persons with mental disorders beginning to use substances such as tobacco in order to alleviate the symptoms of their mental disorders. One support for this hypothesis is the 'tension reduction' hypothesis developed by Cappell & Greeley 87 who argue that persons with anxiety or personal disorders begin to use substance such as alcohol and tobacco because it helps to control their negative moods.
Smoking is a common phenomenon among schizophrenics. A review conducted in 20 countries found that roughly 62% of schizophrenics are also smokers. This led to the formulation of a hypothesis that schizophrenia results to smoking as a result of nicotine helping to reduce the symptoms of the disease. This hypothesis is supported by various studies conducted in Japan, United Kingdom, Israel and Russia that have found a higher incidence of tuberculosis and other bacterial respiratory tract infections among schizophrenics when compared to the population in general. A study in Romania also suggests that there is comorbidity of schizophrenia and tuberculosis. Researchers have, however, stated that this could be as a result of the high incidence of tuberculosis in the country. There are also other studies that have pointed at impairment of lung function among schizophrenics. Researchers have also suggested that smoking contributes to the development of schizophrenia as a result of alteration of neurochemical systems. However, there are no studies that have proven support of this hypothesis. Another study found that the association between schizophrenia and smoking is only applicable in countries where tobacco is easily available.

Smoking has also been associated with other severe mental illnesses such as bipolar and major depression. However, only few studies have explored the relation between these two phenomena. One study reported that 69% of bipolar patients engage in daily smoking compared to 34% in patients with major depression and 23% in the general population. These results together with those on schizophrenics suggest that daily smoking in patients with severe mental disorders is higher than in the general population. Another study suggested that the daily smoking rate in the general population stands at 24% which is much lower than that in schizophrenics which stands at 64% compared to 66% in bipolar patients and 60% in depression patients.

Bipolar patients are associated with decreased cessation of smoking with these patients also having higher odds of becoming current or ever daily smokers. This suggests that there is an increased initiation of smoking amongst bipolar patients. The study also found that there was a higher risk of becoming heavy smokers among bipolar patients. Other confounders that affect this phenomenon such as gender and genetic factors are thought to have an influence on the results of this study de Leon, Gurpegui, & Diaz, 2007()

Two major reasons are given for the increase in smoking rates among patients with severe mental illnesses. The first reason is that there is an increase in smoking initiation as a result of increase in the number of first-time smokers or relapse of ever smokers. The second reason points at a decrease in smoking cessation. This may be linked to the suggested statement that patients with severe mental illnesses experience better quality of life and reduced symptoms of the disease as smokers than as non-smokers. Nicotine has major antidepressant properties and difficulties in cessation of smoking may be associated with depression that comes as a result of these severe mental illnesses Graham, Frost-Pineda, & Gold, 2007()

In a study conducted by Novak et al. (2010)

, the researchers attempted to find the possible genetic factors that predispose patients with severe mental illness to tobacco use. Their focus was as a result of finding new targets for effective treatment of these illnesses. This study dealt with the NR4A gene which has several polymorphisms that may be associated with increased smoking among patients with severe mental disorder. The NR4A gene is also associated with increased drug addiction. The researchers were interested in six SNPs (single nucleotide polymorphisms). The study found that the NR4A3 allele has a positive association with the risk of smoking in patients with bipolar. A similar result with the NR4A3 allele was found in the schizophrenic population. The…