Human Dependence on Tobacco and Opioids: Physiologic Dependence

2015

Physiologic dependence is a factor of significance in opioid dependence and of suspected significance in cigarette smoking. There are three primary aspects of physiologic dependence. The first is important in the maintenance of opioid-taking behavior, in which the emergence of the withdrawal syndrome is correlated with increasingly intense craving scores (). Some analogous findings in animal studies are that the onset of the opioid withdrawal syndrome is correlated with increased rates of drug-taking behavior () and increases in the reinforcing efficacy of opioid drugs (). The second aspect of physiologic dependence to opioids is the increasing propensity of a person in withdrawal to become anxious and to emit aggressive and antisocial acts (). The third aspect of physiologic dependence is the phenomenon of protracted abstinence (), which, in the most rigorous use of the term, refers to physiologic withdrawal signs that are present for more than six months following the onset of opioid abstinence (). Protracted abstinence to opioids has also been well documented in animal studies (). With regard to cigarette smoking, it has been recently postulated that withdrawal phenomena occur and are similar in certain respects to those which characterize opioid dependence (). Specifically (1) the onset of withdrawal increases desire to smoke and also increases the probability of smoking, thus helping maintain patterns of smoking (); (2) the emergence of withdrawal is associated with an increase in levels of anxiety () and an increase in the propensity of the person to emit aggressive or antisocial acts (); (3) there is a protracted withdrawal syndrome whose main characteristic is a long-term recurrent craving ().

While it is becoming more widely accepted that a withdrawal syndrome can emerge during tobacco abstinence, there has been relatively little systematic study or quantification of such a syndrome (Surgeon General’s Report 1979). Available data suggest that measurable physiological changes such as decreased heart rate and blood pressure, and decreased excretion of catecholamines occur within hours after smoking is terminated and last up to 30 days; symptoms such as sleep disturbance, headache, and gastrointestinal discomfort occur and may persist for several days after abstinence ensues; weight gain is a frequent concomitant to abstinence; finally, the most prevalent symptom, desire to smoke, occurs and may recur for many years (). Such a synopsis of possible withdrawal signs and symptoms is somewhat misleading, however, since the kinds of symptoms which have been reported and the temporal patterns of the emergence of these symptoms are not consistent across studies or even across individuals within studies. An important series of human studies would be one similar to those done by the Addiction Research Center on opioids, sedatives, and ethanol, in which the hypothesized withdrawal syndrome is characterized and quantified. If a quantifiable syndrome is verified, then factors could be studied which are of known importance in determining the magnitude of other kinds of drug withdrawal syndromes (e.g., factors such as the preabstinence dosing regimen). Classic substitution procedures could also be done to identify which specific factors attenuate or block the syndrome (e.g., a preliminary study by Fagerstrom, suggests that nicotine-containing chewing gum is partially effective in blocking cigarette withdrawal symptoms).

Another line of research that must be pursued is abstinence studies using animals. Animal studies would be of particular interest since, to date, there have been no demonstrations of either nicotine or tobacco withdrawal in animals, even following prolonged exposure to nicotine () or tobacco (). However preliminary studies have revealed some physiological rebound effects which occur when chronic nicotine administration is terminated in rats (), suggesting the possibility that a withdrawal syndrome may be produced.

 

Selections from the book: “Behavioral Pharmacology of Human Drug Dependence”. Travis Thompson, Ph.D., and Chris E. Johanson, Ph.D., eds. Presents a growing body of data, systematically derived, on the behavioral mechanisms involved in use and abuse of drugs. National Institute on Drug Abuse Research Monograph 37, July 1981.