Does Cigarette Smoking Contribute To Schizophrenia?

Psychosis is a psychiatric disorder in which the affected person is not able to differentiate between what is real and what is imaginary. This condition is also characterized by disordered speech and thought process. Such people also tend to hallucinate a lot and have delusions. A person is said to have a psychotic condition if he or she experiences these symptoms frequently to an extent that it starts to affect their quality of life and relationships. There are a variety of psychotic disorders of which the most common is schizophrenia.[1,2,3]

A person with schizophrenia will have all the symptoms that have been mentioned above. They will feel that the people around them are conspiring against them whereas the reality will be completely the opposite. Various studies have observed a close association of nicotine use in particular cigarette smoking with the onset of schizophrenia.[1,2,3]

Studies have shown that people with psychotic disorders like schizophrenia tend to be heavy cigarette smokers and have no interest in quitting. The reason behind this close link between cigarette smoking and psychotic disorder like schizophrenia is not entirely clear and research is ongoing.[1,2,3] The article below provides more insight to the association between cigarette smoking and schizophrenia.

Does Cigarette Smoking Contribute To Schizophrenia?

A study published in the journal The Lancet mentions that chronic smokers are twice more likely to develop psychotic disorders or schizophrenia later on in life than people who do not smoke. A research for the association between smoking and psychotic disorders has been going on for a long time. Previous studies have shown that people who have psychotic disorders like schizophrenia are more likely to smoke because they find it as a means to counter the side effects of the medication that they take for the disease. The patients also feel an improvement of symptoms of schizophrenia when they smoke cigarettes.[3]

However, some researchers contradict this point and state that if this is the case then people with a diagnosed psychotic disorder should smoke more cigarettes after their diagnosis which is not the case according to the study mentioned above. This has been proved by a meta-analysis done by researchers from King’s College London where evidences from 61 observational studies involving 15,000 smokers and 273,000 non-smokers were closely studied.[3]

The analysis showed that 57% of people who presented with the first symptom of psychosis were smokers. This meant that that people who came to the hospital for the first time complaining of symptoms of psychosis were three times likely to be smokers than healthy people who were a part of the study. It was also observed that chronic smokers also developed the symptoms of psychotic disorders like schizophrenia approximately one year earlier on an average than people who did not smoke. This created a serious doubt on the theory stated earlier that people with psychotic disorders smoked to calm down their symptoms and to counter the side effect of the medications.[3]

However, the researchers state that smoking should be taken as a serious risk factor for the development of psychotic disorder like schizophrenia and not just a result of the illness. Since, only smoking history was taken into account while conducting the meta-analysis, it is not known whether other factors may also contribute to the link between smoking psychotic disorders.[3]

Some researchers have come up with another theory to explain the link between smoking and psychotic disorders like schizophrenia. This theory involves the dopamine system of the brain. It is well known that excess dopamine in the brain is the reason behind why people develop symptoms of schizophrenia. The researchers feel that chronic nicotine exposure tends to increase the levels of dopamine in the brain resulting in increased risk for psychotic disorders. However, they feel that more research needs to be done to better delineate the association between chronic smoking, occasional smoking, and daily smoking and psychotic disorders.[3]

They feel that since there has been clear improvement seen in the symptoms of schizophrenia with smoking cessation, it becomes extremely important for psychologists and psychiatrists to implement this change in habit to see better results in people with psychotic disorders who smoke. Another study done in 2014 at Washington University School of Medicine in Saint Louis observed that people with severe mental disorders like schizophrenia were more likely to have substance abuse problems including smoking cigarettes.[3]

The results of the study showed that people with conditions like schizophrenia were 4 times likely to be heavy alcohol abusers and about 5 times more likely to be cigarette smokers.[3]

In conclusion, there has been a clear association established between cigarette smoking and development of psychotic disorders like schizophrenia. Researchers have come up with various theories about this association. One theory suggests that people with schizophrenia tend to smoke cigarettes more as they experience a significant improvement in symptoms. They also tend to smoke to counter the side effects of the medication they are given for this psychotic disorder.[1,2,3]

However another theory challenges this hypothesis and mentions that if this were the case then the rate of smoking in people with diagnosed psychotic disorder would have been more which was not the case in the study. Another hypothesis observes that smoking increases the levels of dopamine in the brain. This results in the symptoms that are seen with a psychotic disorder like schizophrenia.[1,2,3]

Studies have also shown that people with severe schizophrenia are about 5 times more than likely to be daily cigarette smokers which more or less proves link between cigarette smoking and psychotic disorders like schizophrenia.[1,2,3]

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