Tweaking is a slang term to describe someone visibly under the influence of methamphetamine, sometimes pejoratively. Chronic methamphetamine users are commonly known as tweakers and amongst users the drug itself is sometimes known as tweak. The clinical term is Amphetamine psychosis.
Definition
Tweaking is most often used by the general public to describe someone exhibiting pronounced symptoms of methamphetamine use, including punding (the repetitive performance of useless tasks), hyperactivity, an inhibited ability to relate socially, inattention to bodily hygiene, exaggerated fidgeting, or formication (the false sense of things crawling on or under the skin).
Amongst amphetamine users it sometimes refers only to the negative effects of the drug 's use; other times it may be used describe being under the influence of the drug whether or not this is obvious to others. Users frequently report that the negative effects of methamphetamine use can be abated by remembering to eat, drink and bathe while under the influence, suggesting that the psychosis may sometimes be caused by sleep and food deprivation rather than by the drug directly.