Panic or anxiety can occur in association with intoxication with the following classes of sub- stances: alcohol, caffeine, cannabis, phencyclidine, other hallucinogens, inhalants, stimu— lants (including cocaine), and other (or unknown) substances. Panic or anxiety can occur in association with withdrawal from the following classes of substances: alcohol; opioids; sed- atives, hypnotics, and anxiolytics; stimulants (including cocaine); and other (or unknown) substances. Some medications that evoke anxiety symptoms include anesthetics and anal- gesics, sympathomimetics or other bronchodilators, anticholinergics, insulin, thyroid prep- arations, oral contraceptives, antihistamines, antiparkinsonian medications, corticosteroids, antihypertensive and cardiovascular medications, anticonvulsants, lithium carbonate, an- tipsychotic medications, and antidepressant medications. Heavy metals and toxins (e.g., organophosphate insecticide, nerve gases, carbon monoxide, carbon dioxide, volatile sub- stances such as gasoline and paint) may also cause panic or anxiety symptoms.
The prevalence of substance/medication-induced anxiety disorder is not clear. General population data suggest that it may be rare, with a 12-month prevalence of approximately 0.002%. However, in clinical populations, the prevalence is likely to be higher.
Laboratory assessments (e.g., urine toxicology) may be useful to measure substance intox- ication as part of an assessment for substance/medication-induced anxiety disorder.
Substance intoxication and substance withdrawal. Anxiety symptoms commonly oc- cur in substance intoxication and substance withdrawal. The diagnosis of the substance— specific intoxication or substance-specific withdrawal will usually suffice to categorize the symptom presentation. A diagnosis of substance/medication-induced anxiety disorder should be made in addition to substance intoxication or substance withdrawal when the panic or anxiety symptoms are predominant in the clinical picture and are sufficiently se- vere to warrant independent clinical attention. For example, panic or anxiety symptoms are characteristic of alcohol withdrawal.
Anxiety disorder (i.e., not induced by a substance/medication). Substance/medication- induced anxiety disorder is judged to be etiologically related to the substance/medication.
Substance/medication-induced anxiety disorder is distinguished from a primary anxiety disorder based on the onset, course, and other factors with respect to substances/medica- tions. For drugs of abuse, there must be evidence from the history, physical examination, or laboratory findings for use, intoxication, or withdrawal. Substance/medication-induced anxiety disorders arise only in association with intoxication or withdrawal states, whereas primary anxiety disorders may precede the onset of substance/medication use. The pres- ence of features that are atypical of a primary anxiety disorder, such as atypical age at onset (e.g., onset of panic disorder after age 45 years) or symptoms (e.g., atypical panic attack symptoms such as true vertigo, loss of balance, loss of consciousness, loss of bladder con- trol, headaches, slurred speech) may suggest a substance/medication-induced etiology. A primary anxiety disorder diagnosis is warranted if the panic or anxiety symptoms persist for a substantial period of time (about 1 month or longer) after the end of the substance in- toxication or acute withdrawal or there is a history of an anxiety disorder.
Delirium. If panic or anxiety symptoms occur exclusively during the course of delirium, they are considered to be an associated feature of the delirium and are not diagnosed sep- arately.