Marijuana: Marijuana impairs judgement, slows reaction time, and can alter judgement and memory. Opiates: Morphine, codeine, oxycodone, and other opiates and opioids relieve pain and create a sense of euphoria. Opiates also cause confusion and drowsiness. Sedatives: Used to treat anxiety and sleep disorders, prescription sedatives slow brain activity and breathing, alter depth perception, and impair cognition. Cocaine: Cocaine makes users feel alert and energetic, but those temporary feelings lead to paranoia, anger, and an extreme sensitivity to touch, light, and sound. Methamphetamines: People use methamphetamines for an immediate rush of confidence and energy, but it comes with serious side effects, including paranoia, hallucinations, and convulsions.