Substance-related disorders

Definitions

• • Intoxication. Reversible sx result from the use of a psychoactive substance because of its direct physiologic effects on the CNS. Initial episodes of substance abuse and intoxication may start in the teenage years and may develop into problems of abuse and dependence.

  • Abuse. Substance use continues despite negative consequences that include physical danger or harm, recurrent academic, social, or occupational problems, and impaired functioning in home or social environments.

  • Dependence. Dependence on a substance may be physical or psychological. In physical dependence the patient uses the substance to avoid symptoms of withdrawal. Inhaled and injected agents, other rapidly acting agents, and substances with a short duration of action are more likely to cause physical dependence. In psychological dependence, patients experience a strong "craving" for the substance. Compulsive use is often present, including use of the substance in greater amounts than intended and excessive time spent in acquisition or use of the substance. Other aspects of compulsive use include reduction in other activities favor of substance use and continued use of the substance even when psychological or physical problems develop.

  • Withdrawal. Decreasing or stopping the prolonged use of a substance causes symptoms of withdrawal specific to that substance. These include behavioral, physiological, and cognitive changes that can cause severe distress.

Alcohol withdrawal

Alcohol intoxication

Caffeine: Excessive caffeine can cause insomnia, restlessness, flushing, diuresis, twitches, nervousness, rambling thoughts and speech, tachycardia, and psychomotor agitation. Sx last 6-16 hours. Withdrawal can cause headaches, lethargy, and irritability.

Cannabis. Marijuana or hashish from cannabis leaves cause effects that are due to tetrahydrocannabinol (THC). Synthetic THC is used medically to relieve nausea from chemotherapy, anorexia from AIDS, and increase IOP from glaucoma. Intoxication causes feeling of elation, increased appetite, conjunctival injection, dry mouth, and tachycardia. Cannabis use and dependence, but not withdrawal, may develop.

Nicotine. All forms of tobacco use can contribute to dependence and withdrawal. Nicotine causes catecholamine release and is a CNS stimulant. The incidence of smoking is declining.

Si & Sx: Sx of withdrawal include depression, insomnia, anxiety, irritability, bradycardia, increased appetite and weight gain, and difficulty with concentration.

Tx: Support groups, aversive therapy, nicotine patch/gum, medications (bupropion, clonidine, varenicline.

Cocaine. It can be snorted, smoked, or injected. Crack cocaine is a smoked form of cocaine that is extremely rapid onset. Because cocaine use evokes strong feeling of euphoria, dependence can develop quickly. A short half-life requires frequent dosing, and a great deal of money may be spent in a short time period, leading to theft, prostitution, and drug dealing.

Si & Sx: Intoxication produces euphoria, hyperactivity, anxiety, grandiosity, and impaired judgement. Tachycardia, pupillary dilation, nausea and vomiting, psychomotor agitation, and chest pain or cardiac arrhythmias are possible physical manifestations. Withdrawal sx include dysphoric mood, fatigue, unpleasant dreams, insomnia or hypersomnia, and psychomotor agitation.

Tx: Hospitalization is often necessary to remove the patient from the drug source. Psychological intervention and medical treatment and bromocriptine and desipramine may be useful.

Amphetamine.