What is a drug?


The mention of the word, “drug” evokes different images in different people. For many ordinary people, the word is associated with illicit drugs used outside the boundaries of conventional medicine. Hence the first images that pop into their minds are those of street heroin or cocaine, speed or ecstasy. For clinicians, depending on where they practice, the word also means something negative or positive. The context in which it is used also plays a role in fully understanding what is meant.

Finding a comprehensive medical definition of the term, “drug” is an interesting challenge. The National Cancer Institute defines a drug as,

“Any substance (other than food) that is used to prevent, diagnose, treat, or relieve symptoms of a disease or abnormal condition.”

It outlines that drugs can also affect how the brain and the rest of the body work and cause changes in mood, awareness, thoughts, feelings, or behaviour.

Another definition of the word acknowledges the murky history of the term “drug” in Western societies. Under this definition,

“A drug is any psychoactive substance that can alter the way the mind or body works, regardless of legal status or medical approval. It can be synthetic or produced from natural sources and can be used for a variety of reasons including medicinal, recreational and spiritual.”

This definition, taken from a Sage publication on “Key Concepts in Drugs and Society,” is part of a discussion that acknowledges that drugs are used in a variety of contexts, including outside the medical setting. The publication goes on to highlight the cultural influences on the understanding of the word (as compared to, for instance, the word, “medicine”); and the medico-legal status of drugs as legal, controlled, illegal, illicit, or quasi-legal. Despite the breadth of coverage of the contextual understanding of the term, the weakness with the second definition is that it limits the definition to “psychoactive” substances i.e., drugs that act principally on the brain.

On this podcast, we adopt a definition that encompasses both above definitions. We define a drug as,

“Any substance (other than food) that can alter the way the mind or body works, regardless of legal status or medical approval. It can be used to prevent, diagnose, treat, or relieve symptoms of a disease or abnormal condition; be synthetic or produced from natural sources and can be used for a variety of reasons including medicinal, recreational and spiritual.”

This is in recognition of the rather arbitrary differentiation between a “drug” and a “medicine”. We shall look at practical examples of this shortly. However, at this point it is important to introduce a term that we will try to use for most of our podcasts where relevant.

In the past, when drugs were seen to have been used inappropriately, this was referred to as “drug abuse” and the individuals who were known to be involved were referred to as “drug addicts”. The term “drug addict” is loaded with negative connotations based on stereotypes. In recognition of this, we prefer to use the term, “drug misuser”, which is a more holistic description of problematic drug use.

The National Library of Medicine, quoting the World Health Organisation and the UK Department for Health (2006), defines drug misuse in the following terms,

Drug misuse is defined as the use of a substance for a purpose not consistent with legal or medical guidelines. It has a negative impact on health or functioning and may take the form of drug dependence or be part of a wider spectrum of problematic or harmful behaviour.

For instance, when a patient goes into a pharmacy and buys paracetamol with codeine (co-codamol) for the short-term management of a headache, that is a legitimate use of the medicine. However, if the same patient starts to use the co-codamol inappropriately on a long-term basis, resulting in drug-induced headaches, then the patient becomes dependent on the medicine. That patient has become a “drug misuser.” The legal status of the co-codamol has not changed. It is the conditions under which it is being used that have changed.

Other examples can be cited to illustrate this point. Clinicians will be familiar with patients who have become dependent on prescription and over the counter “drugs” such as opioids, benzodiazepines, other analgesics, and sedatives. Many such patients are otherwise fully functional members of the community and do not regard themselves as “drug misusers.” On the other hand, the deaths of some well-known music stars have been linked with addiction to and overdosages from licenced prescription medication.

Furthermore, consideration must be given to such socially acceptable “drugs” as alcohol and tobacco. Though they are widely consumed and shared in social settings, providing pleasure to millions, only confirmed problem drinkers are regarded as “alcoholics,” a short term for “alcohol-dependent drug misuser”. This is in recognition of the deleterious effects of such misuse on health, social life, and economic well-being; in much the same way as other well-recognised “drugs”. However, rarely do we find, in everyday conversation, people referring to the purchase and consumption of alcoholic beverages as trade in “drugs”. Similarly, it is thanks to the changes in societal perception of tobacco misuse that there is now widespread appreciation of tobacco dependence as a form of addiction to the drug nicotine.

In addition, we also acknowledge that the legal status of many “drugs” is fluid depending on use, culture, geography, and politics. At the time of writing this post, the recreational use of cannabis, for instance, is legal in 18 US states; whereas its medical use is legal in 37. Across the world, there are varying levels of control affecting anything from the whole plant to cannabinoids derived from it.

Finally, we consider that some people like to distinguish between synthetic drugs and naturally derived substances used in a state as close to raw as possible. They regard the former as bad and the latter as more acceptable. This is not justified by an understanding of the underlying mechanisms of action at a molecular level; at which it is observed that the active components are similar, if not identical, and generally have identical mechanisms of action. The natural substances are therefore ‘drugs’ in the same way as the synthetic formulations.

In this podcast, therefore, we trace the history of drugs across social, religious, political and moral boundaries, irrespective of type and origin.  


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