There are a number of other commonly used illicit substances that may lead to a diagnosis of a substance use disorder. These include inhalants, cocaine, methamphetamine, hallucinogens, heroin, and prescription drugs. Inhalant use peaks between seventh and ninth grades, with sustained use more frequent in boys. Indeed, the most serious inhalant abuse is exhibited by children and adolescents who have little access to alcohol or other drugs. Cocaine is a powerfully addictive drug; tolerance and craving are frequently observed. Single or repeated use may result in cardiovascular, respiratory, and neurological complications. Methamphetamine is a potent stimulant drug that has become increasingly widespread and extraordinarily problematic. It has a similar drug structure to amphetamines but more dramatic and more toxic effects on the central nervous system. Dissociative drugs such as phencyclidine (PCP) affect the neurotransmitters glutamate and dopamine, also with unpredictable effects. With characteristics and effects overlapping stimulant and psychedelic drugs, 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) is another abused substance, often used in combination with alcohol or marijuana. Its use i s associated with increases in feelings of well-being, increases in emotional and sensory perception, and decreases in anxiety. Ecstasy’s effects occur via neurotransmitter systems, with immediate life-threatening consequences for some individuals and long-term complications for others (such as damage to serotonin-containing neurons).