Medications and Definitions

Drugs – Physiological tolerance, addiction and abuse

When I give medications to patients for neurological problems, such as attention deficit disorder or acute pain, the thing that almost everyone says is:

I don’t want to become addicted to a medication.

I don’t want a person to become addicted to a medication either.

That’s why I take an extensive history including medical along with social and family histories. The patient’s living arrangements and social situation are also an important factor in screening for patients who might be susceptible to addiction. I get more history if there is any question of addiction arising.

What the problem comes down to is that most people do not know what the definitions of addiction, physiological tolerance and abuse are.

Here we go –

When you take a medication, your body adapts to the medication by increasing the enzymes needed to break down the medication. Because of this, the dose of the drug often has to be increased in order to get the same effect that it originally produced. This is called physiological tolerance, and it is to be expected. The amount that the drug can be increased by is determined by several factors, including, but not limited to, side effects, toxicity, cost, patient history, clinical vigilance, and the doctor’s knowledge of the medication.

One of the best examples of physiological tolerance is coffee. Coffee causes some people to function better at their jobs. By modulating the release of various neurotransmitters, it causes certain blood vessels to constrict and produces an elevation in blood pressure. If you start drinking coffee every day, your body says, “Okay, since caffeine is coming in every day at 10 AM, I’m going to make sure to dilate blood vessels at 10 AM every day so that we can still have a good blood supply to the brain while drinking the coffee.” Because of this, regardless of whether you drink your coffee or not, the body is going to dilate blood vessels at 10 AM every day because it has learned that you take your caffeine drug at 10 AM every day. So, if one day, you do not take your daily dose of caffeine, your body is going to dilate the blood vessels anyway, because it had been reprogrammed to think that caffeine was coming every day at 10 AM. When that happens, you wind up getting a caffeine withdrawal headache! Additionally, if you’re a daily coffee drinker, your body has increased the enzymes to break down the caffeine and get it out of your system. So after drinking coffee for several days or weeks, you might need more cups of coffee throughout the day to give you the same effect that you had when you first started drinking it. This means that you have developed a physiological tolerance it.


Addiction is different. It’s when a person continues to do something despite the fact that it’s harmful to themselves or to others. Addiction, like many diseases, is a combination of genes and the environment. It depends on the personality of the individual and his or her surrounding influences. One person can have a sugar-free, cholesterol-free cookie every day, and that’s fine. If, one day, it turns out that they don’t have any money to buy the cookie and they can say, “Oh well. No cookie for me today,” that person is not addicted to the cookie. However, if they don’t have the money to buy the cookie, and they feel that they need the cookie so much that they have to rob a store to get the cookie, then that’s an addiction. They’re hurting others and, subsequently, themselves.

If a person feels better or happier while taking a medication, that’s not an addiction. If the person asks the doctor to increase the dose of the medication to get a better effect, that’s not an addiction either. If the doctor says that it’s unsafe to raise the dose or continue the medication for whatever reason (liver dysfunction, cardiac toxicity, etc.) and the patient decides to start “borrowing” some medication from a friend, then that’s an addiction. If they decide to start buying the medication from a dealer on the streets, then that’s an addiction. If they go to another doctor and ask for the medication without telling the new doctor that the last doctor did not want the person to get the medication anymore because it was hurting them, that’s also an addiction. The person is hurting himself and others.


Drug abuse is when a drug’s use interferes with a person’s responsibilities, health, social interactions, and/or conduct in society (legal issues), but the person’s symptoms have not met the criteria of drug addiction. Anything a person puts in his or her body that causes a pleasurable sensation has the potential for abuse. Things that are more pleasurable are more likely to be abused.


– Tolerance is a normal physiological response that a person gets to a substance, which often requires an increase in dose to get the desired effect.

– Addiction is a behavior that is governed by genes, the environment, and the coping mechanisms of a person that causes harm to the person and/or to others.

– Drug abuse is when a drug’s use interferes with certain spheres of a person’s life, but their symptoms have not met the criteria of drug addiction.

For a more in depth view of medications that are used in treatment of  attention deficit disorder, please see the Sixteenth chapter, The MS ICE From Both Sides of the Desk, in my book Multiple Sclerosis From Both Sides of the Desk – Two views of MS through one set of eyes.

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