Nocturnal sleep-disturbing nicotine craving: a newly described symptom of extreme nicotine dependence.

In our research on smoking and nicotine dependence we have noticed a sleep disturbance, which is a further symptom of extreme nicotine dependence. We call this symptom "nocturnal sleep-disturbing nicotine craving" (NSDNC). NSDNC is characterised by craving for cigarettes during the individual sleep times. The smoker awakes (one or several times per week) during his regular sleep time, and has to smoke a cigarette before he/she continues sleeping. This symptom can be explained by the decreasing nicotine levels during the sleep time, which results in nicotine craving. However, NSDNC should be carefully separated from other sleep disturbances, or sleep disturbing events (nycturia, medication side effects), when nicotine craving is not the main reason for awakening.