Phencyclidine (PC) interrupts the functions of the neocortex, the section of the brain that controls the intellect and keeps instincts in check. Because the drug blocks pain receptors, violent PCP episodes may result in self-inflicted injuries. Users frequently report a sense of distance and estrangement. Time and body movements are slowed down. Muscular coordination worsens and senses are dulled. Speech is blocked and incoherent. In later stages of chronic use, users often exhibit paranoid and violent behavior and have hallucinations. Large doses may produce convulsions and coma, as well as heart and lung failure. Lysergic acid (LSD), mescaline, and psilocybin cause illusions and hallucinations. The physical effects may include dilated pupils, elevated body temperature, increased heart rate and blood pressure, loss of appetite, sleeplessness, and tremors. The user may experience panic, confusion, suspicion, anxiety, loss of control and flashbacks, even after ceasing use.