Methamphetamine (also referred to as methylamphetamine or desoxyephedrine) is a synthetic stimulant drug used for both medicinal and recreational purposes (the latter use is illegal in most countries). It is sometimes prescribed for ADHD and narcolepsy. It causes euphoria and excitement by acting directly on the brain's reward mechanisms, thus making it highly addictive. Methamphetamine rapidly enters the brain and causes a cascading release of norepinephrine and dopamine (and to a lesser extent, serotonin). Users may become obsessed or perform repetitive tasks such as cleaning, hand-washing or assembling and disassembling objects. Withdrawal is characterized by increased sleeping and eating, and depression-like symptoms, often accompanied by anxiety and drug-craving.