Problem 2. Addiction is learned behaviour
Learning goals
How does conditioning relate to substance use?
What effect does the environment have on addiction? (cue reactivity)
What is the difference between a habit and an addiction?
When does a habit become an addiction?
How can we treat addiction?
Gerevich, J., Bacskai, E., Farkas, L., & Danics, Z. (2005). A case report: Pavlovian conditioning
as a risk factor of heroin 'overdose' death. Harm Reduction
Background
A number of mechanisms leading directly to drug-related death are known. One of the most
widely known variants is where the active substance content of a drug bought on the black
market differs from the accustomed level. Fatal development related to drug overdose
occurs most frequently when the patient used to the drug gives up its use then after a while
attempts to continue addictive behaviour with the same dose used immediately before
withdrawal. The use of drugs in combination also increases the danger of a fatal overdose.
Siegel et al. showed that situation-specific tolerance is capable of preventing the fatal
consequence of a fatal-sized opiate overdose. Siegel interviewed 10 heroin overdose
survivors in an attempt to ascertain whether the overdoses occurred following novel pre-
drug cues. For seven of the overdoses, the drug was administered in an environment not
previously associated with drug use.
The anticipation and preparation for taking the drug triggers responses contrary to the drug
effect in persons already showing drug tolerance. The anticipation preceding the
administration of opiate, acting as a conditioned stimulus, reduced the action of the drug
and so contributed to the development of a mechanism corresponding to tolerance. When
subjects were given opiate without prior indication, they showed a significantly greater
physiological reaction following the full effect of the drug than when they knew what they
were receiving.
52% of the overdose victims of a university hospital in Barcelona administered “in an
unusual setting”.
These cases show that death can be quite clearly attributed to Pavlovian conditioning.
Case presentation
K.J. died with heroin ‘overdose’ given as the cause of death, although the concentration of
heroin was 0,05mg/L (not different from the accustomed, daily dose) and no other
substances were found. The only thing that differed from the previous times he used heroin
was the environment (the public toilet instead of at home).
,Conclusion
The fatal consequence of the heroin injection may have been caused by the failure in the
action of conditioned tolerance. As the figure shows, when a conditioned place preference
arises, the user has to take a bigger dose each time to achieve the same effect as the user
who does not have the opportunity for secondary conditioning with environmental stimuli
since he or she constantly changes the place where the drug is taken. When the drug is
taken in a strange environment the conditioned tolerance does not operate since the
organism is not "expecting" the drug. The end result is that the otherwise accustomed dose
leads to an overdose and thereby to death. This is why the term "overdose" is misleading
since the quantity taken was not greater than other doses taken without fatal complications.
Figure: heroin
concentration levels in case
A after conditioning in an
accustomed place (A1) and
in a new place (A2), and in
a case B without
conditioning.
In this case it could be
determined that the heroin
used by the patients did
not differ in composition
from what they had been
using earlier. The user
probably died because he
did not take the drug in the
accustomed place and circumstances. In the strange, unaccustomed environment the
conditioned tolerance described above reducing the effect of the drug action did not
operate and a relative overdose resulted.
Users familiar with the concept of conditioned place preference could have greater chances
of survival than those who are not aware of it. This is why there is a need for educational
programmes as part of the treatment, making users receiving treatment aware of the nature
and risks of conditioning.
, Drummond, D. (2001). Theories of drug craving, ancient and modern. Addiction, 33-46.
Abstract
The main theoretical models of drug craving are classified broadly into three categories: (1)
phenomenological models; based on clinical observation and description; these have been
influential in classification systems of addictive disorders and in the development of
pharmacological therapies; (2) conditioning models: based on conditioning theory; these
have been influential in the development of cue exposure treatments; (3) cognitive theories;
based on cognitive social learning theory: these have been influential in the development of
cognitive therapies of addiction. It is concluded that no one specific theory provides a
complete explanation of the phenomenon of craving. However, theories of craving grounded
in general theories of human behaviour offer greatest promise, and generate more specific
and testable research hypotheses. The cue-reactivity model shows promise in the
exploration of the relationship between craving and relapse. However, there is need for
further study.
Introduction
Craving found its way into international classification systems as a key symptom of
alcoholism and later alcohol dependence. WHO panel regarded craving as the underlying
basis of the onset of addiction, excessive drinking, ls of control and relapse. Craving
subsequently entered the International Classification of Diseases (ICD) as a key symptom of
alcoholism. The term ‘craving’ had been used in many different ways by different
researchers, with different operational definition.
Although craving is enjoying something of a comeback, there remains a lack of consensus in
the field about the nature of craving, theoretical models that best characterize it, and the
most appropriate ways to measure it.
Some of the craving theories derived from human research do not assign a central role for
craving in the process of addiction or relapse. This does not negate the importance or
relevance of craving in human addictive behaviour.
What is craving?
‘There is often a discrepancy between the standard dictionary definition of craving as “a
strong desire” and how persons with alcohol-related problems use the word to mean “any
desire or urge, even a weak one, to use the substance”. In general craving is taken to be ‘the
conscious experience of a desire to take a drug’.
Phenomenological models
Phenomenological models of craving are essentially descriptive rather than explanatory and
are derived from the interview and observation of clinical addict populations. Craving is
taken to be a symptom of an underlying addictive disorder. Isbell (1955) made a distinction
between physical (or ‘non-symbolic’) and symbolic craving, the former being principally a
manifestation of drug withdrawal, and the latter being a precipitant of relapse after a
prolonged period of abstinence, long after physiological withdrawal had subsided. Subjective
craving for drugs or alcohol has been characterized as having obsessive elements, and the
use of drugs within this model may represent compulsive behaviour in addicts. The strength
of phenomenological models is in their attention to the human experience. Their popularity
in the field may in part be related to the simplicity of having a ‘symptom’ for addiction (i.e.
