Drug abuse I: basic considerations

CHAPTER 37


Drug abuse I: basic considerations


Mind-altering drugs have intrigued human beings since the dawn of civilization. Throughout history, people have taken drugs to elevate mood, release inhibitions, distort perceptions, induce hallucinations, and modify thinking. Many of those who take mind-altering drugs restrict usage to socially approved patterns. However, many others self-administer drugs to excess. Excessive drug use is our focus in this chapter and the three that follow.


Drug abuse extracts a huge toll on the individual and on society. Tobacco alone kills about 440,000 Americans each year. Alcohol and illicit drugs kill another 100,000. In addition to putting people at risk of death, drug abuse puts them at risk of long-term illness, and impairs their ability to fulfill role obligations at home, school, and work. The economic burden of drug abuse is staggering: The combined direct and indirect costs from abusing nicotine, alcohol, and illicit substances are estimated at over $500 billion each year.


Drug abuse confronts clinicians in a variety of ways, making knowledge of abuse a necessity. Important areas in which expertise on drug abuse may be applied include (1) diagnosis and treatment of acute toxicity, (2) diagnosis and treatment of secondary medical complications of drug abuse, (3) facilitating drug withdrawal, and (4) providing education and counseling to maintain long-term abstinence.


Our discussion of drug abuse occurs in two stages. In this chapter, we discuss basic concepts in drug abuse. In Chapters 38, 39, and 40, we focus on the pharmacology of specific abused agents and methods of treatment.




Definitions




Drug abuse

Drug abuse can be defined as using a drug in a fashion inconsistent with medical or social norms. Traditionally, the term also implies drug usage that is harmful to the individual or society. As we shall see, although we can give abuse a general definition, deciding whether a particular instance of drug use constitutes “abuse” is often difficult.


Whether or not drug use is considered abuse depends, in part, on the purpose for which a drug is taken. Not everyone who takes large doses of psychoactive agents is an abuser. For example, we do not consider it abuse to take opioids in large doses long term to relieve pain caused by cancer. However, we do consider it abusive for an otherwise healthy individual to take those same opioids in the same doses to produce euphoria.


Abuse can have different degrees of severity. Some people, for example, use heroin only occasionally, whereas others use it habitually and compulsively. Although both patterns of drug use are socially condemned, and therefore constitute abuse, there is an obvious quantitative difference between taking heroin once or twice and taking it routinely and compulsively.


Note that, by the definition above, drug abuse is culturally defined. Because abuse is culturally defined, and because societies differ from one another and are changeable, there can be wide variations in what is labeled abuse. What is defined as abuse can vary from one culture to another. For example, in the United States, moderate consumption of alcohol is not usually considered abuse. In contrast, any ingestion of alcohol would be considered abuse in some Muslim societies. Furthermore, what is defined as abuse can vary from one time to another within the same culture. For example, when a few Americans first experimented with lysergic acid diethylamide (LSD) and other psychedelic drugs, these agents were legal and their use was not generally disapproved. However, when use of psychedelics became widespread, our societal posture changed and legislation was passed to make the manufacture, sale, and use of these drugs illegal.


Within the United States, there is divergence of opinion about what constitutes drug abuse. For example, some people would consider any use of marijuana to be abuse, whereas others would call smoking marijuana abusive only if it were done habitually. Similarly, although many Americans do not consider cigarette smoking abuse (even though the practice is compulsive and clearly harmful to the individual and society), others believe very firmly that cigarette smoking is a blatant form of abuse.


As we can see, distinguishing between culturally acceptable drug use and drug use that is to be called abuse is more in the realm of social science than pharmacology. Accordingly, since this is a pharmacology text and not a sociology text, we will not attempt to define just what patterns of drug use do or do not constitute abuse. Instead, we will focus on the pharmacologic properties of abused drugs—leaving distinctions about what is and is not abuse to sociologists and legislators. Fortunately, we can identify the drugs that tend to be abused and discuss their pharmacology without having to resolve all arguments about what patterns of use should or should not be considered abusive.




Other definitions

Tolerance results from regular drug use and can be defined as a state in which a particular dose elicits a smaller response than it did with initial use. As tolerance increases, higher and higher doses are needed to elicit desired effects.


Cross-tolerance is a state in which tolerance to one drug confers tolerance to another. Cross-tolerance generally develops among drugs within a particular class, and not between drugs in different classes. For example, tolerance to one opioid (eg, heroin) confers cross-tolerance to other opioids (eg, morphine), but not to central nervous system (CNS) depressants, psychostimulants, psychedelics, or nicotine.


Psychologic dependence can be defined as an intense subjective need for a particular psychoactive drug.


Physical dependence can be defined as a state in which an abstinence syndrome will occur if drug use is discontinued. Physical dependence is the result of neuroadaptive processes that take place in response to prolonged drug exposure.


Cross-dependence refers to the ability of one drug to support physical dependence on another drug. When cross-dependence exists between drug A and drug B, taking drug A will prevent withdrawal in a patient physically dependent on drug B, and vice versa. As with cross-tolerance, cross-dependence generally exists among drugs in the same pharmacologic family, but not between drugs in different families.


A withdrawal syndrome is a constellation of signs and symptoms that occurs in physically dependent individuals when they discontinue drug use. Quite often, the symptoms seen during withdrawal are opposite to effects the drug produced before it was withdrawn. For example, discontinuation of a CNS depressant can cause CNS excitation.



APA diagnostic criteria regarding drugs of abuse


The American Psychiatric Association (APA) has established diagnostic criteria for disorders relating to drugs of abuse. The criteria now in use, published in the fourth edition of the APA’s Diagnostics and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), were released in 1994. Revised criteria will be published in the fifth edition (DSM-5), scheduled for release in 2013. The new criteria, viewable online at www.DSM5.org, differ significantly from the criteria in DSM-IV. Both sets of criteria are summarized in Table 37–1. As the table shows, DSM-IV divides substance use disorders into two major groups: substance abuse and substance dependence. Substance dependence, which can be equated with our definition of addiction, is a more severe disorder than substance abuse. Accordingly, individuals whose drug problem is not bad enough to meet the criteria for substance dependence might nonetheless meet the criteria for substance abuse. In DSM-5, the criteria for substance abuse and substance dependence will be merged into a single, new diagnostic category—substance use disorder—which will replace the two older categories. This change is welcome in that the distinction between substance abuse and substance dependence is somewhat vague, and hence has been a source of confusion.



TABLE 37–1 


American Psychiatric Association Diagnostic Criteria Pertaining to Drugs of Abuse











Diagnostic Criteria from DSM-IV-TR* Proposed Diagnostic Criteria for DSM-5†
Substance Abuse


Individuals who display tolerance, withdrawal, and other symptoms of substance dependence would be diagnosed under Substance Dependence, a more severe disorder, rather than under Substance Abuse.
Substance Dependence



A A maladaptive pattern of substance use, leading to clinically significant impairment or distress, as manifested by three or more of the following, occurring at any time in the same 12-month period:



1. Tolerance, as manifested by either:



2. Withdrawal, as manifested by either:



3. The substance is often taken in larger amounts or over a longer time than intended


4. Substance use continues despite a persistent desire or repeated efforts to cut down or control consumption


5. A great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects


6. Important social, occupational, or recreational activities are given up or reduced because of substance use


7. Substance use continues despite knowledge of a persistent or recurrent physical or psychologic problem that substance use probably caused or exacerbated (eg, drinking despite knowing that alcohol made an ulcer worse)

 Substance Use Disorder

A A maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by two or more of the following, occurring within a 12-month period:



1. Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or home


2. Recurrent substance use in situations in which it is physically hazardous


3. Continued substance use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance


4. Tolerance, as defined by either:‡



5. Withdrawal, as manifested by either:‡



6. The substance is often taken in larger amounts or over a longer period than was intended


7. There is a persistent desire or unsuccessful efforts to cut down or control substance use


8. A great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects


9. Important social, occupational, or recreational activities are given up or reduced because of substance use


10. Substance use is continued despite knowledge of having a persistent or recurrent physical or psychologic problem that is likely to have been caused or exacerbated by the substance


11. Craving or a strong desire or urge to use a specific substance


Severity Specifiers
Moderate: 2–3 criteria positive
Severe: 4 or more criteria positive
Specify If
With Physiologic Dependence: evidence of tolerance or withdrawal (ie, either Item 4 or 5 is present)
Without Physiological Dependence: no evidence of tolerance or withdrawal (ie, neither Item 4 nor 5 is present)



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*Modified from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. Washington, DC: American Psychiatric Association, 2000, with permission. Copyright © 2000 American Psychiatric Association.


†Modified from the proposed diagnostic criteria for a Substance Use Disorder, to be published in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Washington, DC: American Psychiatric Association. Expected publication date: May 2013. Copyright © American Psychiatric Association. The proposed criteria are from the DSM-5 web site—www.DSM5.org—accessed on November 12, 2010.


‡Tolerance and withdrawal are not counted if they develop for medications (eg, analgesics, anxiolytics) taken under medical supervision.

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Jul 24, 2016 | Posted by in NURSING | Comments Off on Drug abuse I: basic considerations

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