Smoking, schizophrenia and depression. What is the connection?
Health and beauty
Science has already shown that people with mental disorders, especially those with depression and schizophrenia, smoke much more often than others. However, until now, researchers have not been able to accurately determine whether this is a causal relationship, and, if so, in which direction: does a mental illness increase the likelihood of smoking or does smoking itself are a risk factor for mental illness.
Researchers from the University of Bristol Research Group, with the support of the Center for Integral Epidemiology and the Center for Biomedical Research, studied the data of the British biobank – 462,690 people of European descent, including 8% of smokers and 22% of former smokers.
The team took an analytical approach – Mendel randomization. The method uses genetic variants associated with various influences (for example, smoking) to test concepts about cause and effect relationships. Thanks to this approach, scientists found evidence that, on the one hand, tobacco smoking increases the risk of developing depression and schizophrenia, and on the other, that these disorders increase the likelihood of smoking (although in the case of schizophrenia the evidence is slightly weaker).
Psychiatry and smoking
The same group of scientists, in collaboration with the University of Amsterdam, had previously concluded that tobacco smoking increases the risk of developing bipolar disorder.
Back in 2016, the UK government mental health committee recommended clearing the country’s psychiatric hospitals of tobacco smoke. New evidence provided the committee with a reason to implement a smoke-free policy. Modern science has all the evidence that this habit can be harmful to mental health, and also confirms sad statistics: a significant percentage of mortality in patients with mental illness is associated with nicotine addiction.
Genetic studies can tell a lot about the effects of smoking on human mental health.
“In the context of overall efforts to reduce the prevalence of smoking, people with mental illness are often ignored,” explains Dr. Robin Wootton, a senior fellow at the School of Psychological Sciences and research leader. “Our work shows how important it is to make every effort so that people don’t start smoking or, when they smoke, get rid of this habit, because its consequences for mental and physical health are enormous.”
“Every day we have more and more data from genetic research,” adds Marcus Munafo, professor of biological psychology at the Bristol School of Psychological Sciences and senior developer of the project. – This gives ample opportunity to use new methods – such as randomization according to Mendel. They, in turn, help in understanding cause-effect relationships. Genetic studies can tell a lot about the effects of smoking on a person’s mental health. ”
That is why, in many countries, the scientific conclusions of such studies form the basis of health programs.