Tolerance is indicated by either (1) larger doses of the substance being needed to produce the desired effect or (2) the effects of the drug becoming markedly less if the usual amount is taken. Failure to fulfil major obligations, ex. absences from work. Exposure to physical dangers, ex. driving while intoxicated. Persistent social or interpersonal problems: withdrawal negative physical and psychological effects. In the dsm-5, the distinction between substance abuse and dependence was dropped and there is now one overarching category: substance-related and addictive disorders. Alcohol abuse/dependence combined with other drugs is referred to as polydrug (polysubstance) abuse synergistic; the effects of each combine to produce a strong reaction. Alcohol dependence may include tolerance or withdrawal reactions. A person who has been drinking heavily for a number of years may also experience a delirium tremens (the dts, which involve alcohol withdrawal delirium) when the level of alcohol in the blood drops suddenly.