To the Editor: An association has been noted between tobacco smoking and anxiety disorders. Himle and associates (1) found a smoking prevalence of 47 percent in a sample of patients with panic disorder. Here we describe two patients with a DSM-IV diagnosis of panic disorder for whom we observed a close relationship between smoking cessation and pharmacologic treatment.
Ms. A, a 29-year-old married Caucasian secretary, reported having many panic attacks in the three months before the evaluation. She had been a smoker since she was 14 years old, and she regularly smoked about 13 cigarettes a day. She told us that with every cigarette she smoked, she experienced dyspnea, dizziness, cold extremities, and tachycardia. She described the symptoms as being similar to those of a spontaneous panic attack but less intense. She could not quit smoking despite her wish to do so and the annoyance these symptoms caused. Each time she tried to quit, she experienced anxiety, insomnia, and agitation. She drank about 55 mg of coffee or other caffeinated beverages daily, but she had no history of alcohol or other drug abuse or dependence.
After two weeks of treatment with 1 mg of clonazepam a day, Ms. A stopped smoking. She denied any nicotine withdrawal symptoms. At two weeks she also reported a complete remission of panic attacks. She complained about mild dizziness during the first week of treatment. After 26 months of follow-up, she still has not smoked.
Ms. B, a 41-year-old married Caucasian lawyer, reported that her panic attacks had begun two years before the evaluation. She had smoked 20 cigarettes a day from the age of 15. She said that smoking decreased the anticipatory anxiety she experienced in relation to her panic attacks. Ms. B said that she rarely used caffeine, and she denied any history of alcohol or other drug abuse or dependence.
Ms. B told us that shortly before the evaluation she decided to quit smoking. However, as soon as she stopped, the frequency, duration, and intensity of her panic attacks increased. She was started on 2 mg of clonazepam a day for her panic attacks, and after three weeks of treatment she reported a complete remission of panic attacks. In addition, as soon as her panic attacks were in remission, she succeeded in quitting smoking. She has been taking the same dosage of clonazepam for 30 months and has not smoked during that time.
Smoking may be a risk factor for the development of panic disorder (2). The symptoms that Ms. A reported when she smoked a cigarette may be subsyndromal panic attacks. The nicotine may have induced sympathomimetic symptoms (3). Ms. B complained that the panic attacks worsened as soon as her smoking habit was interrupted. In her case, the nicotine withdrawal may have had an anxiogenic effect (4). Ms. B quit smoking even though her anxiety symptoms increased. In both cases the panic symptoms and the nicotine withdrawal symptoms were controlled simultaneously, so it is not possible to determine whether the disappearance of panic symptoms was attributable to cessation of smoking or to clonazepam treatment.
The sudden interruption of the smoking habit among patients with panic disorder may increase the anticipatory anxiety related to panic attacks or may trigger withdrawal symptoms similar to panic symptoms. Treatment with a benzodiazepine or another antianxiety agent may help manage anxiety among patients with panic disorder and may also help them quit smoking.
The authors are affiliated with the Laboratory of Panic and Respiration at the Institute of Psychiatry of the Federal University of Rio de Janeiro in Brazil.