premise: Levoamphetamine increases wakefulness.
hypothesis: Amphetamine . At therapeutic doses , amphetamine causes emotional and cognitive effects such as euphoria , change in desire for sex , increased wakefulness , and improved cognitive control . Levoamphetamine , also known as levamfetamine ( INN ) , ( R ) - amphetamine , - amphetamine , and L-amphetamine , is a central nervous system ( CNS ) stimulant known to increase wakefulness and concentration in association with decreased appetite and fatigue .