The opioid system consists of three receptors, mu, delta, and kappa, which are activated by
endogenous opioid peptides processed from three protein precursors, proopiomelanocortin …

The hypothesis that dopamine is important for reward has been proposed in a number of
forms, each of which has been challenged. Normally, rewarding stimuli such as food, water …

The theory is advanced that the common denominator of a wide range of addictive
substances is their ability to cause psychomotor activation. This view is related to the theory …

Drugs of abuse are ve y powerful reinforcers, and even in conditions of limited access
(where the organism is nof dependent) these drugs will motivate high rates of operant …

The molecular and cellular actions of three classes of abused drugs—opiates,
psychostimulants, and ethanol—are reviewed in the context of behavioral studies of drug …

Alcohol consumption is an integral part of daily life in many societies. The benefits
associated with the production, sale, and use of alcoholic beverages come at an enormous …

In this review we will critically assess the hypothesis that the reinforcing effect of virtually all
drugs of abuse is primarily dependent on activation of the mesolimbic dopamine system …

The natural incentives that shape behavior reach the central circuitry of motivation trans-
synaptically, via the five senses, whereas the laboratory rewards of intracranial stimulation …

Epidemiological and clinical data indicate high comorbidity between depression and drug
dependence that may reflect an attempt to self-medicate with drugs of abuse. The present …

Drug addiction, also known as substance dependence, is a chronically relapsing disorder
characterized by (1) compulsion to seek and take the drug,(2) loss of control in limiting …