From The Art and Popular Culture Encyclopedia
Social inhibition is a conscious or subconscious constraint by a person of behavior of a social nature. The constraint may be in relation to behavior, appearance, or a subject matter for discussion, besides other matters. There are a number of reasons for social inhibitions, including that the person fears that the activity, appearance or discussion will meet with social disapproval. For example, a person with a low level of social inhibition might focus their conversation on subjects that others feel uncomfortable about or which are not commonly discussed in that particular social group; while a person with a high level of social inhibition would avoid touching on such subjects.
Inhibitions can serve necessary social functions, reducing or preventing certain antisocial impulses from being acted on.
The consumption of alcohol or certain drugs may reduce inhibitions with effects varying from person to person. At low concentrations of blood alcohol, social inhibitions may be reduced. However, some substances may actually strengthen these inhibitions: for instance abuse of stimulants may lead to anxiety and heightened inhibition. This is more common in drugs with dysphoric effects.