The Natural History of Opiate Dependence

Individuals addicted to opiates often become dependent on these drugs by their early twenties and remain intermittently dependent for decades. Biological, psychological, sociological, and economic factors determine when an individual will start taking opiates. However, it is clear that when use begins, it often escalates to abuse (repeated use with adverse consequences) and then to dependence (opioid tolerance, withdrawal symptoms, compulsive drug-taking). Once dependence is established, there are usually repeated cycles of cessation and relapse extending over decades. This "addiction career" is often accompanied by periods of imprisonment.

Treatment can alter the natural history of opiate dependence, most commonly by prolonging periods of abstinence from illicit opiate abuse. Of the various treatments available, MMT, combined with attention to medical, psychiatric, and socioeconomic issues, as well as drug counseling, has the highest probability of being effective.

Addiction-related deaths, including accidental overdose, drug-related accidents, and many illnesses directly attributable to chronic drug dependence explain one-fourth to one-third of the mortality in an opiate-addicted population. As a population of opiate addicts ages, there is a decrease in the percentage who are still addicted.

There is clearly a natural history of opiate dependence, but causative factors are poorly understood. It is especially unclear for a given individual whether repeated use begins as a medical disorder (e.g., a genetic predisposition) or whether socioeconomic and psychological factors lead an individual to try and then later to compulsively use opiates. However, there is no question that once the individual is dependent on opiates, such dependence constitutes a medical disorder.

Diagnosis of Opioid Dependence

Opioid dependence (addiction) is defined as a cluster of cognitive, behavioral, and physiological symptoms in which the individual continues use of opiates despite significant opiate-induced problems. Opioid dependence is characterized by repeated self-administration that usually results in opioid tolerance, withdrawal symptoms, and compulsive drug-taking. Dependence may occur with or without the physiological symptoms of tolerance and withdrawal. Usually, there is a long history of opioid self-administration, typically via intravenous injection in the arms or legs, although recently, the intranasal route or smoking also is used. Often there is a history of drug-related crimes, drug overdoses, and family, psychological, and employment problems. There may be a history of physical problems including skin infections, hepatitis, HIV infection, or irritation of the nasal and pulmonary mucosa. Physical examination usually reveals puncture marks along veins in the arms and legs and "tracks" secondary to sclerosis of veins. If the patient has not taken opiates recently, he or she may also demonstrate symptoms of withdrawal, including anxiety, restlessness, runny nose, tearing, nausea, and vomiting. Tests for opioids in saliva and urine can help support a diagnosis of dependence. However, by itself, neither a positive nor a negative test can rule dependence in or out. Further evidence for opioid dependence can be obtained by a naloxone (Narcan) challenge test to induce withdrawal symptoms.

Evidence That Opioid Dependence Is a Medical Disorder

For decades, opioid dependence was viewed as a problem of motivation, willpower, or strength of character. Through careful study of its natural history and through research at the genetic, molecular, neuronal, and epidemiological levels, it has been proven that opiate addiction is a medical disorder characterized by predictable signs and symptoms. Other arguments for classifying opioid dependence as a medical disorder include:

source: National Institutes of Health Consensus Development Program.