Link between smoking and schizophrenia
Psychiatrists Dr. Amila Isuru and Dr. Mahesh Rajasuriya re-examine evidence to establish fact and reveal insidiousness of tobacco industry
Smoking may worsen schizophrenia!
The smokescreen to the contrary that has been created by powerful tobacco companies and researchers with vested interests has been dispelled by two Sri Lankan Psychiatrists.
Their convincing evidence titled ‘ Tobacco smoking and schizophrenia: re-examining the evidence’ has been published by the prestigious medical journal, ‘ BJPsych Advances’ ( British Journal of Psych Advances).
The two researchers who have cleared the smokescreen by poring over and critically reviewing all scientific material published on smoking and schizophrenia are the Consultant Psychiatrist at the Tissamaharama Hospital, Dr. Amila Isuru and Senior Lecturer in Psychiatry, Dr. Mahesh Raj as uri ya who is attached to the Colombo Medical Faculty.
‘ BJPsych Advances’ of the Royal College of Psychiatrists, in which the Sri Lankan Psychiatrists’ major findings have been published, is promoted as “essential” reading for practising mental health professionals who need to be kept informed of current ideas, techniques and developments in psychiatry. This journal plays an active role in the continuous medical education of psychiatrists.
Smoking is an important cause of premature deaths among those suffering from schizophrenia and the prevalence of smoking is strikingly high among them, say Dr. Isuru and Dr. Rajasuriya.
‘Premature deaths’ mean that people with schizophrenia who smoke, usually die 20 years earlier than normal people. “One the main reasons for this is tobacco smoking,” reiterates Dr. Isuru.
Before giving the backdrop of why they took a long and hard look at all studies on tobacco smoking and schizophrenia, they explain what schizophrenia is.
“Schizophrenia is a severe mental illness, usually long-lasting and episodic, characterised by two types of symptoms, positive and negative,” says Dr. Isuru, pointing out that the positive symptoms are delusions and hallucinations.
Delusions are firmly- held beliefs – somebody is trying to poison or monitor you. These are a result of a pathological process of thinking and are usually false and not shared by others. Hallucinations are perceptions, sound, sight, smell, touch or taste that arise without a real physical presence of a stimulus, says Dr. Rajasuriya, citing the example of hearing a voice when nobody is actually speaking to you.
Positive symptoms tend to come in episodes and go away too as the episode is brought to an end, usually by treatment, it is learnt.
“Negative symptoms tend to develop over time and stay on without disappearing even after an episode (of positive symptoms) is over. Poor sociability, lack of normal emotional variation, reduced hygiene and lower functional level are some negative symptoms, which are more resistant to treatment,” says Dr. Isuru.
It was about four years ago that Dr. Isuru came across a huge study on smoking as a risk factor for schizophrenia. “The findings were powerful,” he says and with it also came the realization that many were not aware of the impact of smoking on schizophrenia.
So he launched himself along this pathway – to tell the world vital findings on smoking and schizophrenia.
Dr. Rajasuriya, meanwhile, says that it has been interesting and also puzzling why there is a high prevalence of smoking among those with schizophrenia, when compared to those suffering from other mental illnesses or those without any mental illnesses.
This has been the subject of speculation for a long time with several
“beliefs” coming to the fore, the Sunday Times learns.
There are three major hypotheses that have surfaced over the years, the Psychiatrists point out. They are:
First hypothesis – the self-medication hypothesis
Second hypothesis – smoking as a possible risk factor for the development of schizophrenia
Third hypothesis – shared genetic vulnerability, which means that certain genes confer vulnerability for both schizophrenia and nicotine dependence
Tackling the self- medication hypothesis, Dr. Isuru says that there has been a belief that smoking alleviates (makes less severe) some symptoms of those with schizophrenia and also the side-effects of medications. This has led to many doctors not advising people with schizophrenia to give up smoking.
“This is while the stigma surrounding schizophrenia seems to promote the thinking that the patients are ill anyway and as such it does not matter that they smoke even though it is a health hazard,” says Dr. Rajasuriya.
Dr. Isuru is quick to point out that the impressions that the symptoms as well as the side-effects of medication are alleviated are being propagated by tobacco companies.
In fact, good quality studies have clearly shown and repeatedly proven that schizophrenia patients who smoke have more severe symptoms, he underlines, adding that the symptom-alleviation hypothesis has been “busted” over and over again. Therefore, this argument is no longer valid, as it has been proven that smoking creates more severe symptoms and those suffering from schizophrenia should be told that they should stop smoking.
This should be a powerful motivating factor to get schizophrenia- smokers to quit, says Dr. Rajasuriya.
They point out that the tobacco industry in the United States of America (USA) had to sign a master settlement agreement in 1998, in response to multiple cases of litigation against it. The result was around 70 million pages of tobacco industry documents and nearly 20,000 other media materials becoming accessible to the public.
The scrutiny of these documents had clearly revealed how the industry deceived the public by advertising and other methods and suppressing opposing research, the Psychiatrists said.
One study analysing these documents had pointed out that the tobacco industry had directly funded research on the hazards of stopping smoking that supports the self-medication hypothesis. The industry had promulgated the image of nicotine as a ‘ therapeutic agent’ rather than an ‘addictive agent’, it is learnt.
“The most scandalous revelation is, perhaps, that the tobacco industry funded research studies that showed the benefits of smoking in schizophrenia, which had provided one of the strongest neurobiological evidence bases for the self- medication theory,” says Dr. Isuru.
Getting down to smoking as a risk factor for the development of schizophrenia, Dr. Isuru and Dr. Rajasuriya, hold the second hypothesis to the light.
The risk factors for schizophrenia spectrum disorders are well established. Researchers have recently been focusing on smoking as a risk factor for developing schizophrenia spectrum disorder, they explain, stressing that a high prevalence of smoking in the first episode of psychosis is well established. But the schizophrenia-smoking link is not that straightforward.
The Psychiatrists, however, quote an extensive prospective Israeli study which surveyed 14,248 military recruits devoid of major psychopathology to examine the onset of smoking and the subsequent risk for schizophrenia. The study participants, all adolescents, had initially been screened for smoking and it had been found that 28.4% smoked at least one cigarette per day. Subsequently, they were followed up for 4-16 years.
“There was a significant association between daily smoking levels recorded at the initial screening and the risk of developing schizophrenia during the study period,” says Dr. Isuru.
Tobacco smoking increases the risk of psychosis more than three times and is similar to the impact of using cannabis, says Dr. Rajasuriya.
What is psychosis?
Psychosis is a group of disorders characterized by delusions and hallucinations and very much a part of schizophrenia, explains Dr. Rajasuriya.
“Psychosis is a severe group of disorders which can have a huge negative impact on a person’s education, ability to work, social interactions and personality,” reiterates Dr. Isuru, with Dr. Rajasuriya adding that it has a huge impact on the family and thus on the community and the country.
Meanwhile, a shocking statistic revealed by the Psychiatrists is that 50% of cigarettes in the USA are smoked by patients with mental illness. So, for the tobacco industry this is a very captive audience.
Next, Dr. Rajasuriya deals with the third hypothesis of ‘ shared genetic vulnerabilities’. This means that there is a set of genes which cause both – a tendency to smoke and a tendency to get schizophrenia.
However, he adds that genes alone cannot be considered, as smoking is a complex human behaviour.