The biological models for understanding drug abuse focus on organic brain changes due to substance abuse, and how this fosters an adjustment to the drug and further causes a physical dependence. The psychosocial theories have an emphasis on drugs as a way to cope with feelings and psychological discomfort. Is it two irreconcilable perspectives, or may be different perspectives can complement each other to help us understand the depth and complexity of drug abuse and addiction? One trend is abundantly clear however: No longer is addiction seen as a disease of the will or a moral imperfection.
Abuse of naturally occurring and human-modified substances dates at least as far back as the discovery of alcohol through fermentation. While it is uncertain just when alcohol was first used, current evidence dates it as long ago as 10,000 BC. In more modern times, Dr. Benjamin Rush (often called the father of psychiatry) mentions addiction to alcohol in his 1812 treatise, Medical Inquiries and Observations upon the Diseases of the Mind and calls it a “disease of the will”. Ideas about addiction, its causes and treatments have changed substantially since then – Dr. Rush’s mainstay treatment was bloodletting and ‘sweat therapy’. In spite of this, addiction remains a complex disease with no clear cure.
In current medical practice, definition often equates to treatment, so understanding just what addiction refers to is important. Unfortunately, there is no one definition that captures what it means to be addicted in every case. For this reason, it has become a matter of picking off a list of symptoms – more than a set number of these (usually 3 or more from a list of 7 in a 12-month period).
(Note: in this list, sometimes a behavior is under consideration rather than a substance – this covers the usage of the word when applied to shopping, gambling or other process addictions.[modified from addiction and recovery. org])
- Tolerance – the phenomenon of increased substance use to obtain a similar effect.
- Withdrawal – physical or mental symptoms that occur primarily from the removal of the substance. For drug abuse, this and tolerance have well understood physiological mechanisms.
- The substance is taken over longer periods and in larger amounts than intended. This automatic ratcheting up of dosage is marked in illegal drug abuse.
- A persistent desire and lack of success in attempts to lessen use. Short term abstinence will be followed by usage that quickly returns to pre-abstinence norms and above. This, along with number 3 is felt by patients as a spiraling loss of control.
- A great deal of time is spent in obtaining, using or recovering from the effects of the addictive substance.
- Activities that are seen as important are sacrificed because of drug use. These can be work related, personal goals, recreational or social. Combined with number 5, the experience is that the substance begins to ‘take over my life’.
- Use is continued despite the knowledge that it is harmful, either physically, psychologically or socially.
To see how these are applied, and a current (Jan, 2010) debate on their application to sex-addiction, see this pair of articles in Psychology Today: What Is He Thinking? By Michael Bader D.M.H. and the rebuttal, Why sex-addiction is not an excuse – The difficult reality of diagnosing addictions by Adi Jaffe.
Withdrawal and Tolerance
While the psychosocial aspects of addiction are still being clarified, the phenomena of tolerance and withdrawal are comparatively well understood. The most accepted model is that of receptor site changes, over time, in the addicted patient.
Dispositional tolerance has to do with less of the additive substance reaching the active site. This can happen when a person becomes more efficient at metabolizing the drug. For example, if the enzymes for detoxifying a substance are up-regulated in the liver, first-pass metabolism is increased, reducing the amount of active substance more quickly than in a naïve patient. Giving a competitive agonist (naloxone for opiates) will also produce dispositional tolerance, because the agent blocks the active site and prevents binding of the abused drug.
Tolerance also occurs by cellular mechanisms. By decreasing the number of receptors (down-regulation) for a particular substance, cells mute the effects. Another cellular mechanism is a feedback response to whatever neurotransmitter the drug is increasing. The baseline for the neurotransmitter (either secondary to substance administration or because the substance itself mimics a neurotransmitter) is elevated and the normal production is reduced.
Finally, cellular mechanisms may be responsible for increasing the removal of either the drug or consequential neurotransmitters – making the body more efficient at removal, which presents as tolerance.
Withdrawal is a playing out of the consequences of tolerance. The body has modified its way of doing business and set a new level of homeostasis. In effect, the abused substance has become part of this new ‘normal’. Removing the substance results in a sometimes overwhelming (and perhaps fatal) suite of symptoms that can be thought of as a ‘negative overdose’. All of the physical changes that led to tolerance now require the drug for the body to operate properly.
It should be emphasized that tolerance and withdrawal happen pharmacologically with many drugs at therapeutic doses. Weaning is a common technique to avoid withdrawal in such mundane drug classes as steroids and anti-depressants.
Beyond the physiology of addiction, there are the real psychological and social harms that occur. These are now seen as having almost as much weight in the addiction process as the pharmacological effects. The reason for this is the high rate of recidivism among drug users who have undergone treatment and have been abstinent for months or even years. The actual substance has long disappeared from their system, yet users may still return to their drug of choice.
Psychosocial mechanisms also may help explain why someone abuses a drug in the first place. No physical addiction mechanism can account for man’s propensity to seek out ways to alter our own mental state.
The broadest definition of addiction treats it as a biopsychosociological phenomenon. The bio part covers evidence that genetics probably has a large role in both who become addicted and how deep the addiction will become. One trend is abundantly clear however. No longer is addiction seen as it was in Dr. Rush’s day – a disease of the will or a moral imperfection. Rather, while society at large may still stereotype addicts as failed human beings (in both the moral and character sense), medical professionals see more clearly the underlying disease process.