As with disorders of alcohol use, The American Psychiatric Association’s DSM-IV identifies two primary disorders of drug use: drug abuse and drug dependence. The diagnostic criteria for drug abuse and dependence parallel those for alcohol abuse and dependence. Drug abuse is defined as continued use of a psychoactive substance in spite of clinically significant impairment or distress. Drug dependence is defined as abuse along with evidence of addiction, including tolerance, withdrawal, inability to quit or cut down, and/or use of the drug becoming increasingly important in the individual’s life.

Comparison between Alcohol and Drugs

Although similar, drug and alcohol use disorders also differ in a number of important ways. First, drug use disorders are a more heterogeneous group, depending on which particular psychoactive substances are used pathologically. Second, most drugs of abuse are illegal, while alcohol use is legal (>21 years of age). Finally, the Navy has a policy of "zero tolerance" toward drug abuse, which greatly differs from its stance toward alcohol use disorders. Because of these differences, disorders of drug use, particularly in the Navy, tend to be more difficult to identify and manage, and their prognosis is generally poorer.

Commonly abused psychoactive substances include sedatives/hypnotics/anxiolytics, opioids, cocaine, amphetamines, phencyclidine, hallucinogens, cannabis, and inhalants. Nicotine is also an important drug of abuse and addiction, but it is managed differently given its (waning) social sanction. Among adolescents, marijuana is the most frequent substance of abuse after alcohol and tobacco. The next most common, perhaps, but certainly of greater medical consequence is the use of amphetamines, including "crystal" methamphetamine. Cocaine abuse and dependence are declining in some populations, and problems related to the use of hallucinogens, PCP, and inhalants are rare. Sedative abuse and dependence are often iatrogenic.

Consider drug abuse and dependence in patients with personality or other psychiatric disorders, criminal behavior, drug-seeking behavior, or factitious illness. Most drug abusers also abuse alcohol and tobacco. Patients with sexually transmitted disease, hepatitis, pneumonia, tuberculosis, and HIV disease should be questioned regarding drug use. Always remember to assess and document potential for suicide and homicide.

The physical manifestations of intoxication with, and withdrawal from substances of abuse, are summarized in the October 5, 1990 issue of The Medical Letter. Sedative/hypnotics cause slurred speech, an unsteady gait, and nystagmus. Opiates cause respiratory depression, coma, and hypotension, while withdrawal provokes marked agitation, dilated pupils, and upper respiratory infection symptoms. Cocaine is extremely addicting, producing intense euphoria and hallucinations within minutes of IV use or when smoked (crack). It can also produce severe dysphoric states, with extremes of depression, paranoia, hyperactivity, or suicidal behavior. Patients may have seizures, fever, hypothermia, and arrhythmias. Death from myocardial infarction, aortic rupture, hypertensive emergency, or placental abruption has been described. Phencyclidine (PCP) causes acute psychosis with agitation, violence, and disorientation. Marijuana rarely causes any detectable physical symptoms other than conjunctival injection.

Every patient suspected of a drug use disorder should receive a complete history, physical exam (including neurologic exam), and mental status exam. Date of first use, heaviest use, longest period of abstinence, amount, frequency, time of last use, route of administration, circumstances of use, and reactions to use are all important elements of the HPI. Sexual and legal histories, family histories of drug use, and histories of exposure to HIV and other infectious agents should also be obtained. Cognitive function should always be assessed in someone suspected of a drug use disorder since some abusable substances impair memory and other higher cortical functions.

Few laboratory findings (other than toxicology screen) are associated with primary disorders of drug use. However, a CBC, chest x-ray, and liver functions should be checked for anyone suspected of having an infection (e.g., septicemia, local vasculitis), hepatitis, or a pulmonary problem (e.g., pulmonary embolus, emphysema) secondary to psychoactive substance use.

Your job as a GMO is to diagnose the abuse or dependence, manage any acute toxicity or withdrawal, and recommend long-term treatment. The Navy or Marine Corps will decide whether to retain the sailor for treatment (rarely) or to separate him or her administratively or legally after NJP or court martial.

1. The American Psychiatric Press Synopsis of Psychiatry, edited by Robert Hales and Stuart