Regular smokers feel better when smoking than not smoking, and empirical studies confirm that nicotine reinstatement relieves feelings of stress, depression and anger. These acute mood changes have led to the belief that cigarette-derived nicotine can provide medicinal benefits for smokers. However, prospective studies of adolescents who take up cigarette smoking find that they report increased levels of anxiety, stress and depression. Furthermore, adults who quit smoking report enduring mood improvements. Thus the prospective data shows that the nicotine derived from cigarettes leads to heightened distress. The empirical patterns of mood change reported by regular smokers show why nicotine dependency is psychologically damaging. Regular smokers report average moods when replete with nicotine, but suffer mood deteriorations in-between cigarettes. Thus the supposed mood gains of smoking only represent the temporary relief of withdrawal symptoms. This mood relief becomes conditioned with smoke inhalation, which is why cigarettes are regarded positively by smokers. However, the repetitive experience of irritability and other abstinence symptoms in between cigarettes paradoxically causes smokers to suffer worse daily moods than non-smokers. The stronger the nicotine dependency the greater the mood decrements, helping to explain why disadvantaged individuals often smoke heavily and find quitting difficult. In conclusion, there is no empirical evidence that cigarettes provide medicinal benefits, but extensive data showing that nicotine dependency heightens psychological distress in tobacco smokers.