Smokers (individuals who smoked 100 or more cigarettes lifetime, or 26 or more cigarettes lifetime and weekly for two consecutive months) were asked about problems they might have had in the first 24 hours after they stopped or cut down on cigarettes. They were queried about each DSM-IV nicotine withdrawal symptom (see Table 1): irritability, restlessness, concentration problems, depressed mood, increased appetite, sleep problems, nervousness and decreased heart rate, within the context of a smoking cessation (or reduction) attempt that they remember most clearly (if more than one attempt). The interview was designed to help the respondent to focus on one particular episode of nicotine abstinence/reduction and asked “At that particular time, did you cut down, or did you completely stop smoking cigarettes? Please tell me more about that time. What do you remember most clearly about that time?” Subjects not endorsing four or more withdrawal symptoms within 24 hours of stopping or cutting down on cigarettes for the initially chosen episode were asked: “Has there been a time when you had 4 or more of the [nicotine withdrawal] problems
