Tobacco Info

From Tobacco Info No. 3 - November 2010
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Depression and smoking don’t mix

Teens using cigarettes to ‘self-medicate’ may be making symptoms worse

It is quite common for teenagers to reach for a cigarette to help ‘self-medicate’ for bouts of depression. However, Canadian researchers have found that smoking may actually increase symptoms in adolescents.

“We were trying to examine if self-medication worked in teens. We asked teens if they thought that cigarettes were improving their mood, and followed them over time to see what effect smoking had on their mood long term,” said Michael Chaiton of the Ontario Tobacco Research Unit. Chaiton, along with Jennifer O’Loughlin of the University of Montreal Hospital Research Centre, co-authored a study involving 1,293 high school aged teenagers from grades 7-11. The teens completed as many as 20 questionnaires about their cigarette use to affect mood.

“This observational study is one of the few to examine the perceived emotional benefits of smoking among adolescents,” said Chaiton, adding that it is also the first study in this age group to “demonstrate the long-term trend of perceived smoking-related psychobiological function on depressive symptoms. Although cigarettes may appear to have self-medicating effects or to improve mood, in the long term we found teens that started to smoke reported higher symptoms of depression.”

The study, titled Use of cigarettes to improve affect and depressive symptoms in a longitudinal study of adolescents, comprised 1,293 Montreal adolescents who were enrolled in the Canadian Nicotine Dependence in Teens (NDIT) trials and were between the ages of 12 and 13. Follow-ups were conducted with these participants every three months for a period of five years.  The investigators then examined the 662 teenagers (61% female) who had smoked during the three months prior to any of the 20 questionnaires issued.

Participants were divided into three groups: teens who had never smoked; smokers who did not use cigarettes to self-medicate, improve mood or physical state; and smokers who used cigarettes to self-medicate. They were then asked to rate their symptoms of depression on a scale ranging from felt too tired to do things; had trouble going to sleep or staying asleep; felt unhappy, sad, or depressed; felt hopeless about the future; felt nervous or tense and worried too much about things.

“Before smoking, all the adolescents had roughly the same level of depressive symptoms, but after they started smoking, depression levels were much higher [among smokers],” said Chaiton. “Basically, we found that teens who reported that they used cigarettes to improve mood and functioning had higher levels of depressive symptoms, and were more likely to become depressed in the future.” 

The findings, published in the medical journal Addictive Behaviors in July, demonstrate that the teens who reported higher self-medication results also had higher scores for symptoms of depression. According to the report, these results show that the perceived benefits may simply come from alleviating the symptoms of nicotine withdrawal and craving.

“This repeated cycle of craving-satisfaction-craving-satisfaction that can occur many times a day for kids may lead to a higher level of depression over time and to worse outcomes,” said Chaiton. “Self-medication scores may be useful in identifying a population that is  susceptible to depression. A significant number of teens use cigarettes in an attempt to feel better, but, in the long term, smoking wasn’t helpful in controlling their mood and likely made them feel worse.  It’s important to correct this misperception among youth themselves, but also among practitioners who may avoid addressing smoking when dealing with mental health issues.”

A study conducted at the University of Cincinnati College of Medicine in 2000 found similar links between smoking and depression, estimating that smoking may actually be the cause of teen depression rather than an attempt to self-medicate.

The investigators in this study looked at two groups. The first had some 8,000 teens that smoked and, according to the medical definition, were not depressed. The second group was composed of almost 7,000 teens who were not currently smokers, but who scored high on symptoms of depression. Among those who were not originally suffering from depression the following year, cigarette smoking was found to be the strongest predictor of developing depression. In the other group, when all possible contributing factors to teen smoking were considered, depression did not prove to be a strong predictor of heavy smoking.

A more recent study conducted by Boden, Fergusson and Horwood titled Cigarette smoking and depression: tests of causal linkages using a longitudinal birth cohort, revealed persistent significant associations between nicotine-dependence symptoms and depressive symptoms. Structural equation modelling suggested that the best-fitting causal model was one in which nicotine dependence led to increased risk of depression. The findings of the researchers from the University of Otago in New Zealand, published in the British Journal of Psychiatry in June 2010, suggest that the co-morbidity between smoking and depression arises from two routes: the first involving common or correlated risk factors and the second a direct path in which smoking increases the risk of depression. Therefore, there exists a cause and effect relationship between smoking and depression in which cigarette smoking increases the risk of symptoms of depression.

Chaiton and his team will continue to follow-up with participants, who are all in their 20s now. “We’re interested in seeing if this effect persists into adulthood and if we see improvements as these youth quit smoking. There are also indications that this self-medication scale may identify a group uniquely at risk for depression.  Finding appropriate substitutes for self-medication may prevent a lifetime of smoking and serious mental illness,” he said.

– by Joe Strizzi