Why more and more passive smokers end up depressed

Smoking a cigarette in the presence of your child, family members or friends, is likely to send them to hospital with a mental illness.

A new study done in Scotland and supported by Kenyan scientists warns of increasing cases of passive smokers checking into hospitals with mental illnesses.

The study findings say while smokers are known to suffer from high rates of depression and other mental health problems, even people exposed to second-hand smoke are at significantly increased risk and are more likely to be hospitalised with mental illness.

Second-hand smoke

Known as the Scottish Health Survey, the study analysed about 5,560 non-smokers and 2,595 smokers. One of the key findings released last week was that non-smokers exposed to second-hand smoke were 1.5 times as likely to suffer from symptoms of psychological distress as unexposed non-smokers.

About 14.5 per cent of those studied were found to experience psychological distress — a medical condition that includes both mild and severe forms of sadness, frustration, anxiety and a number of other negative mood states. Higher exposure was associated with higher psychological distress.

“Exposure to second hand smoking is associated with psychological distress and risk of future psychiatric illness in healthy adults,” say the study authors. “These concordant findings using two different research designs emphasise the importance of reducing second hand smoking exposure at a population level not only for physical health but also for mental health.”

The study comes at a time when the prohibition of public smoking in Nairobi and other towns is not being enforced as expected, with people adhering to the law only while in the city centre. In some workplaces and entertainment centres, non-smokers remain exposed to the dangers of nicotine and other thousands of chemicals found in the cigarettes.

Published in the Archives of General Psychiatry, the study warns such greater exposure to smokers increases the risk of developing mental illness among passive smokers. “Though psychiatric hospitalisations were rare over all, they were almost three times as common for the exposed non-smokers,” the study says.

“This research goes some way toward suggesting nicotine is having some sort of impact on mental health,” said Dr Mark Hamer, the lead author and a senior research fellow at University College London. Prof David Ndetei, a senior lecturer of psychiatry at the University of Nairobi explains that like an active smoker, the passive smoker suffers from withdrawal symptoms associated with addiction to nicotine, the substance found in cigarettes.

When inhaled, nicotine makes a person feel better, but stressed or anxious when its effect wears off. The same goes for non-smokers, who after inhaling a lot of cigarette smoke, suffer from stress and depression when they withdraw from the environment where smoking has been taking place.

“Children and adults exposed to passive smoking for long times especially in the house, workplace or entertainment places, are likely to suffer from nicotine withdrawal symptoms,” says Prof Ndetei. “People who are stressed or have a mental problem are likely to hang around in areas where people smoke even when they are non-smokers. The smoke they inhale from those smoking makes them feel better.”

But when they leave the place and the effect of nicotine wears-off, they become depressed. That is why active smokers will go for another cigarette after they feel stressed. Studies in animals have found tobacco to induce negative moods, and may be a direct cause of psychiatric illness.

According to these studies, a passive smoker inhales many of the dangerous tobacco particles as he or she breathes both “side stream” smoke from the burning tip of the cigarette and “mainstream” smoke that has been inhaled and then exhaled by the smoker.

Epidemiologic Catchment Area (ECA) survey conducted a couple of years ago among 3,000 people in the St. Louis area found non-smokers to have a 2.9 per cent risk of developing lifetime frequency of major depression compared to a 6.6 per cent among active smokers. It also found that about 70 per cent of male habitual smokers and 80 per cent of female habitual smokers had major depression.

Lung cancer

Findings of this and the Scotland study builds on earlier studies which have shown exposure to cigarette smoke by non-smokers also increases their risk of developing lung cancer, heart attacks, and respiratory difficulties, among others. Adverse health effects include pneumonia and bronchitis, coughing and wheezing, worsening of asthma, middle ear disease, and possibly neuro-behavioural impairment and cardiovascular disease in adulthood.

According to information on tobacco by the World Health Organisation (WHO), the risk of lung cancer in non-smokers exposed to passive smoking is increased by between 20 and 30 per cent, while the excess risk of heart disease rises by 23 per cent, with children being at greater risk from adults’ smoking.

“A pregnant woman’s exposure to other people’s smoking can harm her foetus. The effects are compounded when the child is exposed to passive smoking after birth,” says WHO. Sir Richard Doll, a British epidemiologist who demonstrated smoking as a cause of deadly cancer warned that “an hour a day in a room with a smoker is nearly a hundred times more likely to cause lung cancer in a non-smoker than 20 years spent in a building containing asbestos.”

In addition to the non-smokers, the Scotland study says the active smokers who do it in combination with alcohol intake are even at greater risk of experiencing psychiatric symptoms. In age-adjusted analyses, adults with a higher nicotine level had an elevated risk of psychological distress.

Another study done in Sweden established that heavy smoking combined with heavy alcohol consumption and low mental well-being among smokers was associated with increased risk of suicides all over the world. Kenya has banned public smoking to protect non-smokers from smoking related health effects. To protect active smokers, companies that manufacture cigarettes are required to label their products with discernible information on the negative effects of smoking.

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