The effects and dangers of different drugs vary so much that it would be impossible to describe here all the signs and symptoms of even the most common drugs.
Many drugs, such as marijuana and LSD, cause the user's pupils to dilate. Heroin, on the other hand, may cause the pupils to contract. Alcohol intoxication can be very obvious when the drinker is stumbling and slurring her speech, but less obvious when she simply seems tired. Longtime alcoholics may become very skilled at hiding their drinking, and even the keenest observer may miss it. Drinking to get drunk is a high-risk behavior that may or may not indicate dependence. Recognizing someone who has a problem or addiction is not easy. Your job – remember - is not to diagnose, but to REFER!
People who abuse prescription drugs may act more strangely when they are unable to obtain their drugs of choice then when they are intoxicated, and taking the drug may return them to an apparent state of "normalcy." They may swallow pills quite openly, saying they have a prescription and need the medicine to sleep, stay calm, or stop smoking. And all this may be true without changing the fact that they are substance-dependent. If you notice this behavior ... let us know.
Finally, because everyone knows that certain drugs are illegal, users of narcotics and other "street drugs" are likely to go to great lengths to keep their addiction secret.
What all this means is that substance abuse is easy to miss. It is also easily confused with other phenomena, including brain injury and stroke, the effects of crying or insomnia or too much sleep, mental illnesses, or simply having an unusual personality.
Sometimes substance abuse may seem quite obvious. Yet delirium, total irrationality, extremely red eyes that can barely stay open, constant dozing off, unpredictable outbursts and extreme agitation, confused speech, and other strange behaviors can all be signs of many things, not just substance abuse. But when one or more of these behaviors shows up in someone who has previously not exhibited them, drugs may be involved. Either way, that person needs a referral for help!
It is often impossible to know that drugs are being used unless you observe them being ingested, smoked, snorted, injected and so forth, which is unlikely, or a person admits to using, or you receive reliable reports--as opposed to gossip and rumors--that a person uses. It is important that you pay attention, inform when you have suspicion, and make appropriate referrals.