The Diagnostic and Statistical Manual-IV-TR (DSMIV-TR)) describes three basic types of substance-related disorders. Substance use may be either Substance Dependence or Substance Abuse. A third category is Substance-Induced Disorder, which includes mental or physical problems that result solely from the drug's chemical effects on the body.

According to the DSMIV-TR, there are eleven basic drug classes: alcohol, amphetamines (speed), caffeine, marijuana (grass), cocaine, hallucinogens (LSD, Ecstasy), inhalants (Poppers, glue, solvents), nicotine, opioids (heroin, morphine), phencyclidine (PCP, angel dust), sedatives (Valium), and a general "other" category that includes less-common substances and over-the-counter medications. A diagnosis is given for either dependence or abuse for any of these drug categories.

Substance dependence is defined as physical or psychological dependence. For example, if a person has a physical dependence, s/he may experience tolerance or withdrawal.

  • Tolerance means a person needs more of the substance to get high than when s/he first began using it. Natural tolerance can run in families and may be a sign that a person has an increased risk for developing dependence. If tolerance is present, a person can take large amounts of a substance without appearing intoxicated or high.

  • Withdrawal means that a person gets sick if s/he cuts down or stops using the substance. Often, this is why a person continues to use the substance, so s/he can avoid the unpleasant effects of physical withdrawal. In the past, withdrawal was associated with "addiction." But today, we recognize that withdrawal includes varying degrees of physical dependence. Symptoms may include shaking hands, racing pulse, agitation, nausea, or hallucinations. Sudden withdrawal from some substances, such as alcohol or sedatives, is dangerous.

Psychological dependence means that a person has lost control over his/her drug use. A pattern of compulsive use is present, and moderation is no longer possible. Often, denial plays a strong role: People think they can control the habit, while in fact they are using more energy and focus in obtaining the substance and recovering from its effect.

Substance abuse is a pattern of compulsive use. Generally, when teenagers are diagnosed with a substance disorder, they have a pattern of "binge" use. Not all "recreational" use is a disorder, but excessive use is Substance Abuse. Binging may occur during weekends, parties, or other social occasions. To be considered an "abuser," a person's drug use must cause significant problems and have a negative impact on his/her life. The effects of abuse may affect school, work, legal, family, and social relationships. While less severe than dependence, substance abuse can wreak havoc. Even if a teenager drives while intoxicated only once, the results can be tragic. If drug use impacts a child's life in any of the following ways, s/he qualifies for a diagnosis of substance abuse:

  • Drug use when it's physically dangerous, such as driving while intoxicated, engaging in risky sports, unprotected sex, or club dancing (Raves, as they're called) to the point of heat exhaustion
  • Criminal behavior or juvenile delinquency, such as stealing to get money for drugs, disorderly public conduct, or violence
  • Problems functioning at home, school, or work; signs include spending excessive time behind closed doors, avoiding chores, a change in academic performance, suspension from school, or missing work
  • Problems with social relationships, such as arguments with authority figures (teachers, coaches, or parents) or a pattern of defiant or secretive behavior that may be out of character

Substance-induced disorder is diagnosed when someone experiences psychiatric symptoms that are solely related to substance use or withdrawal. For example, depression, anxiety, sleep problems, and hallucinations may occur. But it's important to distinguish these substance-induced symptoms from a preexisting condition. Further, any symptoms should disappear within a month or so after substance use has stopped. can determine the nature, extent, and pattern of substance use

The diagnostic process can also determine if the youth has related problems, such as anxiety, depression, or ADHD. Often, these other disorders coexist with substance disorders and may contribute the problem. Once a substance disorder is diagnosed, it's important for a child or adolescent to admit s/he has a problem. For treatment to be successful, a person must make the decision to stop using the substance. Seeking or accepting help is an important part of recovery.