单项选择题

Smoking Can Increase Depressive Symptoms in Teens While some teenagers may puff on cigarettes to “self-medicate”（自我治疗） against the blues,scientists at the University of Toronto and the University of Montreal have found that smoking may actually __51_ depressive symptoms in some teens. “This observational study is one of the few to examine the perceived _52__ benefits of smoking among teens,” says lead researcher Michael Chaiton, a research associate at the Ontario Tobacco Research Unit of the University of Toronto. “_53__ cigarettes may appear to have self-medicating effects or to improve mood, in the long _54__ we found that teens who started to smoke reported higher depressive symptoms.” As part of the study, some 662 high school teenagers completed up to 20 questionnaires about their use of cigarettes to _55___ mood. Secondary schools were selected to provide a mix of French and English participants, urban and rural schools, and schools _56__ in high, moderate and low socioeconomic neighborhoods. Participants were divided into three _57___: never smokers; smokers who did not use cigarettes to self-medicate, improve mood or physical _58__; smokers who used cigarettes to self-medicate. Depressive symptoms were measured using a scale that asked how often participants felt too tired to do things; had _59__ going to sleep or staying asleep; felt unhappy, sad, or depressed; felt hopless about the future; felt vexed, antsy or tense; and worried too much about things. “Smokers who used cigarettes as mood _60__ had higher risks of elevated(提升) depressive symptoms _61__ teens who had never smoked,” says co-researcher Jennifer O’Loughlin, a professor at the University of Montreal Department of Social and Preventive Medicine. “Our study found that teen smokers who reported emotional benefits from smoking are _62__ higher risk of developing depressive symptoms.” The _63__ between depression and smoking exits _64__ among teens that use cigarettes to feel better. “It’s _65__ to emphasize that depressive symptom scores were higher among teenagers who reported emotional benefits from smoking after they began to smoke,” says Dr. Chaiton.

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