A new study shows a link between regularly smoking cigarettes in adolescence and paranoia.
According to the researchers, they found that the co-occurrence of paranoia with tobacco use was largely explained by genetic influences. Similar results for other types of psychotic experiences were also reported, including having hallucinations and disorganized thinking, which were also associated with tobacco use in teenagers, they report.
“While the links between drugs such as cannabis [with] paranoia and hallucinations have been reported before, much less is known about the relationship between tobacco use and mental health problems,” said senior author Dr. Angelica Ronald, a professor of psychology and genetics at Birkbeck, University of London in the UK.
“In particular, we do not really know why tobacco use and mental health problems often co-occur. In these new findings from our lab, we show that using tobacco is to some degree heritable and that some of the same genetic influences on using tobacco also play a role in experiences such as feeling paranoid.”
The study’s findings are based on the Twins Early Development Study, a large sample of twins born in England and Wales between 1994 and 1996.
More than 3,700 adolescent twin pairs took part in this study when they were aged 16. Of these, 31.4 percent reported smoking cigarettes within the past year, with 12.1 percent identifying as occasional smokers, and 5.2 percent as regular smokers.
Adolescents also reported on their paranoia and other experiences, such as having hallucinations and disorganized thinking, while their parents reported on issues such as a lack of motivation, social withdrawal, and their teenager seeming emotionally flat.
The researchers found that the frequency of adolescent cigarette smoking was associated with having experiences such as paranoia, with regular smokers having more psychotic symptoms and experiences than non-smokers and occasional smokers.
The associations remained even after accounting for several other possible factors, such as gender, socioeconomic status, cannabis use, prenatal maternal smoking, sleep disturbances, and stressful life events, according to the study’s findings.
Environmental influences accounted for about two-thirds of the differences in adolescent smoking behavior, and one-third of the differences were due to genetic influences, the researchers reported.
However, the researchers urge caution in interpreting the findings. They note that the reported association between tobacco use and psychotic experiences was modest and that their study does not show whether tobacco use causes or worsens psychotic symptoms and experiences, only that they are associated with one another.
Nevertheless, they say the findings could be important because, if confirmed, tobacco use could be a modifiable risk factor for psychosis.
The study was published in the Journal of the American Academy of Child and Adolescent Psychiatry.