Chemical dependence; sometimes defined in terms of physiological dependence, as evidenced by tolerance or withdrawal; at other times, defined in terms of impairment in social and occupational functioning resulting from the pathological and repeated use of a substance. In the latter definition, tolerance and withdrawal symptoms may be present but are not essential.
The behaviors and effects associated with substance dependence include taking of the substance to relieve or avoid withdrawal symptoms; taking larger amounts or using it over a longer period than intended; unsuccessful efforts to cut down or control intake; interference with meeting major role obligations at work, school, or home; recurrent use in situations in which it poses a physical hazard (e.g., driving, operating machinery); or substance use taking precedence over important social, occupational, or recreational activities.
State in the habitual use of a drug or other product at which adverse symptoms result upon withdrawal from use. Dependence may be physical (caused by habitual use of, e.g., alcohol or heroin) in which case withdrawal symptoms may include sweating, nausea and vomiting, or tremors; or psychological (involving repeated use of tobacco or some soft drugs, such as amphetamines), in which case withdrawal may cause restlessness, sleeplessness, or depression.
A pervasive and excessive need to be taken care of when no physical reason makes such care necessary. Dependence leads a person to become clingy, submissive, and fearful of separation. Dependent people have great difficulty making ordinary day-today decisions, such as which shirt or blouse to wear. They are so passive that they allow others, usually parents or a spouse, to make decisions for them, and they have great difficulty expressing disagreement with others, particularly people they depend on because they fear losing the relationship in the event of conflict. A dependent person shows little initiative and rarely does things on his or her own. The person may go to excessive lengths to win support and care. Since dependent people are preoccupied with fears of being left to care for themselves, they urgently seek a new relationship to provide support when a current relationship ends. Dependent people are typically pessimistic and self-doubting, belittling of t heir own abilities, and often refer to themselves as “stupid.” They seek out protection and dominance from others because they lack faith in themselves. Dependent individuals may endure long-term physical or sexual abuse rather than end an abusive relationship out of fear of being left alone and independent. Dependence can be a sign of a psychological disorder, such as panic disorder, agoraphobia, or depression. If the condition exists in the absence of another disorder or a general medical condition, it may mean the person has a dependent personality disorder. There is no known cure for this disorder, although psychotherapy can be helpful.
The physical and/or psychological effects produced by the habitual taking of certain drugs, characterized by a compulsion to continue taking the drug. In physical dependence withdrawal of the drug causes specific symptoms ( withdrawal symptoms), such as sweating, vomiting, or tremors, that are reversed by further doses. Substances that may induce physical dependence include alcohol and the hard drugs morphine, heroin, and cocaine. Dependence on hard drugs carries a high mortality, partly because over dosage may be fatal and partly because their casual injection intravenously may lead to infections such as hepatitis. Treatment is difficult and requires specialist skills. Much more common is psychological dependence, in which repeated use of a drug induces reliance on it for a state of well-being and contentment, but there are no physical withdrawal symptoms if use of the drug is stopped. Substances that may induce psychological dependence include nicotine in tobacco, cannabis, and many ‘soft’ drugs, such as barbiturates and amphetamines.
Physical or psychological reliance on a substance or an individual. A baby is naturally dependent on its parents, but as the child develops, this dependence lessens. Some adults, however, remain partly dependent, making abnormal demands for admiration, love and help from parents, relatives and others.