Failure to restrain impulses, functions, or actions that ordinarily can be regulated consciously (e.g., aggressive actions, sexual impulses, bladder and bowel emptying). In relation to alcohol and other substances, loss of control refers to an impaired ability to modulate the amount or frequency of substance intake once any amount of the substance has been administered. Such loss of control, or impaired control, is regarded as one sign of dependence on the substance used.
With respect to drug use, the inability of one who is drug dependent to consistently predict the frequency of use or the amount consumed once use has begun.