Are "social drugs" (tobacco, coffee and chocolate) related to the bipolar spectrum?

Background: Across all ages and cultures, mankind has always used substances in order to induce pleasurable sensations or desirable psychophysical states. These substances, notably caffeine, tobacco, alcohol and chocolate, can be labeled 'social drugs'.

Methods: We analyzed the social drug habits of 562 patients suffering from mood disorders, according to DSM-IV-R criteria (major depressive episode, recurrent depression, bipolar type I and II disorders and depression not otherwise specified).