"Speed" warps time: methamphetamine's interactive roles in drug abuse, habit formation, and the biological clocks of circadian and interval timing.

The indirect dopamine (DA) agonist methamphetamine (MAP) is evaluated in terms of its impact on the speed of temporal processing across multiple time scales involving both interval and circadian timing. Behavioral and neuropharmacological aspects of drug abuse, habit formation, neurotoxicity, and the potential links between interval and circadian timing are reviewed. The view that emerges is one in which the full spectrum of MAP-induced effects on timing and time perception is both complex and dynamic in as much as it involves DA-glutamate interactions and gene expression within cortico-striatal circuitry spanning oscillation periods ranging from milliseconds to multiple hours. The conclusion is that the psychostimulant properties of MAP are very much embedded within the context of temporal prediction and the anticipation of reward.