In both animals and man, stimulants such as the amphetamines and cocaine are reinforcing and thus motivate repeated drug-taking behaviour and leading to abuse. Although this class of drugs seems to act by different biological mechanisms in the central nervous system, it has been suggested that their action to increase dopaminergic neurotransmission is crucial to the reinforcing properties of these compounds. However, increasing evidence suggests that a number of other neurotransmitters/neuroregulators, possibly in conjunction with dopamine, are part of the complex neurochemical systems which underlies various aspects of stimulant abuse behaviours. Examples of possible influences of noradrenaline and corticosterone will be discussed.