When used in the physiological sense, the term intoxication is broader than substance intoxication as defined here. Many substances may produce physiological or psychologi- cal changes that are not necessarily problematic. For example, an individual with tachy- cardia from substance use has a physiological effect, but if this is the only symptom in the absence of problematic behavior, the diagnosis of intoxication would not apply. Intoxica- tion may sometimes persist beyond the time when the substance is detectable in the body.
This may be due to enduring central nervous system effects, the recovery of which takes longer than the time for elimination of the substance. These longer-term effects of intoxi- cation must be distinguished from withdrawal (i.e., symptoms initiated by a decline in blood or tissue concentrations of a substance).
Criteria for substance withdrawal are included within the substance-specific sections of this chapter. The essential feature is the development of a substance-specific problematic be- havioral change, with physiological and cognitive concomitants, that is due to the cessation of, or reduction in, heavy and prolonged substance use (Criterion A). The substance-specific syn- drome causes clinically significant distress or impairment in social, occupational, or other im- portant areas of functioning (Criterion C). The symptoms are not due to another medical condition and are not better explained by another mental disorder (Criterion D). Withdrawal is usually, but not always, associated with a substance use disorder. Most individuals with withdrawal have an urge to re—administer the substance to reduce the symptoms.
Route of Administration and Speed of Substance Effects
Routes of administration that produce more rapid and efficient absorption into the blood- stream (e.g., intravenous, smoking, intranasal ”snorting") tend to result in a more intense intoxication and an increased likelihood of an escalating pattern of substance use leading to withdrawal. Similarly, rapidly acting substances are more likely than slower-acting substances to produce immediate intoxication.
Duration of Effects
Within the same drug category, relatively short-acting substances tend to have a higher potential for the development of withdrawal than do those with a longer duration of ac- tion. However, longer-acting substances tend to have longer withdrawal duration. The half-life of the substance parallels aspects of withdrawal: the longer the duration of action, the longer the time between cessation and the onset of withdrawal symptoms and the lon- ger the withdrawal duration. In general, the longer the acute withdrawal period, the less intense the syndrome tends to be.
Use of Multiple Substances ously or sequentially. In these cases, each diagnosis should be recorded separately.
Laboratory analyses of blood and urine samples can help determine recent use and the specific substances involved. However, a positive laboratory test result does not by itself indicate that the individual has a pattern of substance use that meets criteria for a substance—induced or sub- stance use disorder, and a negative test result does not by itself rule out a diagnosis.
Laboratory tests can be useful in identifying withdrawal. If the individual presents with withdrawal from an unknown substance, laboratory tests may help identify the sub- stance and may also be helpful in differentiating withdrawal from other mental disorders.
In addition, normal functioning in the presence of high blood levels of a substance sug- gests considerable tolerance.
Individuals ages 18—24 years have relatively high prevalence rates for the use of virtually every substance. Intoxication is usually the initial substance-related disorder and often be- gins in the teens. Withdrawal can occur at any age as long as the relevant drug has been taken in sufficient doses over an extended period of time.