talk incessantly about any subject at hand and often chain-smoke. Because the body develops a tolerance to amphetamines, abusers must increase their dosages to obtain the psychic effects they desire. Tolerance to all the effects does not develop uniformly. Even a “tolerant” abuser can experience high blood pressure, abnormal heart  rhythms,  loss  of  appetite,  excitability, talkativeness, trembling hands, enlarged pupils, heavy perspiration, and stereotypic compulsive behavior. In serious cases, a drug psychosis resembling paranoid psychosis develops. In addition, violent behavior may follow  the  use  of  amphetamines  because  of unpredictable mood changes. Amphetamines for medical purposes are available by prescription under a variety of trade names. They are also manufactured in clandestine laboratories as crystalline powder, as tablets, and in a variety of liquid forms; they are then sold through illicit channels. DEPRESSANTS. –The drugs depress the central nervous system. Abusers of depressants, such as barbiturates and certain tranquilizers, exhibit most of the symptoms of alcohol intoxication with one important exception: no odor of alcohol is detected on their breath. Depressant abusers may stagger or stumble and frequently fall into a deep sleep. In general, depressant abusers lack interest in activity, are drowsy, and may appear to be disoriented. Since depressants depress the central nervous system, they are prescribed in small doses to reduce restlessness and emotional tension and to induce sleep. Some are valuable in the treatment of certain types of epilepsy. Continued and excessive dosages of depressants result in slurred speech, faulty judgment, a quick temper, and a quarrelsome disposition. Overdoses, particularly when taken in conjunction with alcohol, result in unconsciousness and death unless the user receives proper medical treatment. Therapeutic doses cause minimal amounts of psychological dependence, whereas excessive doses taken over a period of time result in both physical and psychological dependence. Abrupt withdrawal, particularly from barbiturates, can produce convulsions. Depressants are exceedingly dangerous. HALLUCINOGENS. -Hallucinogens are chemicals extracted from plants or synthesized in laboratories. LSD, mescaline, and  PCP  (phencyclidine) psilocybin and psilocin, are all examples of hallucinogens. Although openly and irresponsibly promoted as a means of expanding consciousness, hallucinogens have yet to be proved valuable medically. Hence, neither standard dosage forms nor markings exist that make visual identification possible. Illicit labs produce hallucinogens in the form of capsules, tablets, powders, or liquids; peddlers and users use many methods to transport or hide the drugs. For example, LSD has been found in sugar cubes, candy, paper, aspirin, jewelry, liquor, cloth, and even on the back of postage stamps. Persons who use hallucinogenic drugs (such as LSD) are highly unlikely to do so while at work. They usually use such drugs in a group situation under special conditions  designed  to  enhance  their  effect. Hallucinogens distort the user’s perception of objective reality. They produce illusions involving the various senses and, if taken in large doses, can produce hallucinations. Persons under the influence of hallucinogens usually sit or recline quietly in a trance-like state. On occasion, users become fearful and experience a degree of terror that may cause them to attempt to escape from the group situation. An important point to remember is that the effects of LSD may recur days, or even months, after someone has taken it. The effects of hallucinogens are not solely related to the drug. They are modified by the mood, mental attitude, and environment of the user. Hallucinogens usually distort or intensify the sense of perception and lessen the user’s ability to discriminate between fact and fantasy. Users may speak of “seeing” sounds and “hearing” colors. Their judgment of direction and distance is generally out of proportion. Their pupils dilate and their eyes become extremely sensitive to light. They  commonly  experience  restlessness  and sleeplessness until the drug wears off. The drugs have an unpredictable mental effect on persons each time they take them. As with stimulants and depressants, the user of hallucinogens may develop a psychological dependence.  However,  unlike  depressants, hallucinogens have not been shown to produce a physical dependence. VOLATILE  CHEMICALS. -The  volatile chemicals include model airplane glue, lacquer thinner, gasoline, fingernail polish remover, and lighter fluid. The substances contain xylol, creosol, naphtha, benzol, tetraethyl lead, and other chemicals that can cause severe damage to the body by attacking the oxygen level. 3-11