This post is mostly to clarify, to journalists, what the difference between drug tolerance, drug dependence, and drug addiction is. Why does some loser like me on a tiny corner of the internet need to clarify this? Apparently, no journalists can be bothered to do any actual research.
I have read time and time again in several prominent publications that all pain medications lead to addiction. No ifs ands or buts, always. Therefore, they are dangerous and evil, we should hate them, and doctors shouldn’t prescribe them.
But who really cares? If these medicines are so widely regarded as dangerous, no one must need or use them, right? This stuff is only used by hard core junkies on the street to get high. These are the narcotics they’re always going after on COPS.
These are all excellent points. It’s too bad none of them are true.
First of all, no one uses the term “narcotic” correctly. In fact, it is so widely misused that the medical profession has completely given up. Now, “narcotic” is referred to as a legal term, and medical professionals use terms like opioids. So, what is a narcotic, really? A narcotic refers to opium, opium derivatives, and their semi-synthetic or fully synthetic substitutes. This means cocaine, meth, LSD, steroids, DXM, and yes, even marijuana are ruled out. None of these are narcotics, no matter how much the police insist upon calling them that. Why does law enforcement do this? I don’t know. Probably because “narcotic” is a scary sounding word. Opium is a milky substance produced by certain species of poppy flowers, and it contains a great many chemicals, called opiates. An opioid is any substance that binds to opioid receptors in the central nervous system (or “any substance which behaves pharmacologically like morphine”). The terms opioids and narcotics are, in essence, synonymous.
So, what are opioid receptors?
The brain works by sending messages between cells to tell those cells what to do. These messages are sent by chemicals known as neurotransmitters. Examples of neurotransmitters include melatonin, dopamine, serotonin, epinephrine (adrenaline), endorphins, and so on. Neurotransmitters that are produced directly by our bodies are referred to as endogenous ligands. These transmitters are made to fit into certain spots on the outsides of cells, like a key into a lock. These spots are called receptors. The ligand for 5HT receptors is serotonin. The ligands for (parts of) NMDA receptors include glutamate and aspartate (specifically, N-methyl D-aspartate). It is thought that all receptors have corresponding ligands, but there are several receptors we know of that we have yet to discover natural ligands for (such as the sigma receptors). A ligand for the various opioid receptors is endorphin.
(Update: A few people emailed me to let me know the ligand for sigma receptors is angeldustin. This isn’t entirely correct. The theorized ligand used to be called angeldustin, but is currently referred to as endopsychosin (never say neuroscientists don’t have a sense of humor). The reason it was called this is because PCP appears to exhibit effects on the sigma receptors, and PCP tends to make you a bit of a nut. The argument goes along the lines of “why would the brain have a natural ability to mimic the effects of PCP on the brain, and in effect make itself nutso.” Some theories of schizophrenia point at the sigma receptors. The antipsychotic drug haloperidol appears to have effects on sigma receptors. We really have absolutely no idea what they do.)
Drugs that act on the brain do so by manipulating neurotransmitters or receptors in one way or another. Some drugs prevent neurotransmitters from being produced, some prevent them from being reabsorbed, and others mimic the transmitters themselves.
In general, there are three ways that a transmitter works on a receptor. In one way, the transmitter binds to the receptor and activates it, causing changes within the cell. These transmitters are called agonists. In the second way, a transmitter binds to the receptor but doesn’t activate it, and these transmitters are called antagonists. In the third way, a transmitter binds to the receptor and partially activates it, and these are appropriately named partial agonists. One interesting property of partial agonists is that they tend to “normalize” receptor activity levels. In the presence of a low amount of neurotransmitter, the partial agonist will increase receptor function. In the presence of a high amount of neurotransmitter, however, the partial agonist will limit receptor activity. This is a type of negative feedback. The best example I can think of negative feedback is a thermostat: when it’s hot, it turns the heat off; when it’s cold, it turns the heat on.
When you take a narcotic painkiller, the drug binds to and activates various opioid receptors in the brain, spinal cord, and gastrointestinal tract. Drugs like this are opioid agonists. The opioid receptors influence many things, most notably pain and mood. Wait, the gastrointestinal tract? Yes, actually, one of their most noted side-effects is constipation, which can be severe. Opioids reduce gut motility, which means it slows down your bowels, which gives your body more time to absorb water from the bowels, which solidifies the stool. If you’ve ever taken Immodium for diarrhea, you’ve taken a very potent opioid (although, one which does not cross the blood-brain barrier and thus it is only active in the gastrointestinal tract, so it does not cause analgesia or euphoria). The effects and side-effects are enourmous and complicated, and if you’re interested in how exactly these things happen, see the Wikipedia article on opioid receptors. We’ll sum it up by saying that opioids invoke pain relief, or analgesia, feeling nice, or euphoria, and, over time, the need to increase the dosage to achieve the same effects, or drug tolerance.
The one we’re mostly concerned about is tolerance. Tolerance occurs because your brain is an amazing thing. When there are larger than normal amounts of opioids in your system for an extended period of time, the brain compensates by down-regulating the receptors. That is, it starts creating less of these receptors, so that the opioids have a lesser effect at the same dose. In order to achieve the original effects (be it analgesia or, in the case of an abuser, euphoria), the dosage must be increased so that more receptors are reached. Other than needing increasing dosages, this is not necessarily a bad thing. This is simply how the brain compensates. This is simply reality. Anyone who takes opioids for an extended period of time will experience tolerance.
So, what does this all entail? Tolerance usually implies dependence. Is this a bad thing? Maybe. Drug dependence means that your brain has become tolerant to this drug to one degree or another, and if you suddenly stop taking it, your brain chemistry is suddenly messed up. This manifests as withdrawal symptoms, which can be severe.
So wait, the journalists are right? Anyone that takes opioids for a while will go into withdrawal? Well, yes, but that doesn’t mean that you’re addicted to the drugs. This just means that, as your brain readjusts itself to the way it was before the drugs were introduced, you won’t be having a great time. This can be avoided by slowly and carefully stepping down your dosage over a period of time. By doing this, the brain adjusts slowly to each new dosage, and withdrawal is minimal or nonexistent. This means that people can take opioids for a week, a month, or even years and, so long as their dose is slowly reduced, they’ll return to their pre-opioid state just fine, and (assuming the reason for taking the drugs in the first place is gone) will be perfectly normal.
Okay, then, what is addiction? Well, many people hold somewhat personal views about this, but I’ll discuss how medical professionals view it. Addiction is defined as a psychological dependence on something. The key difference is that one is “all in their heads,” and one is physical. Whether it’s drugs, sex, food, gambling, whatever. In the case of drug addiction, someone thinks they need a particular drug in order to be normal. You can see the confusion. People who are drug dependent actually do need the drug to be normal. Drug addicts only think they do. They crave the drug. They’ll do anything to get more of it, including selling everything they own, including their bodies. Addicts will continue to do the activity despite harmful consequences to the individual’s health, mental state or social life. Addicts are usually dependent on their drug of choice, and usually experience withdrawal fairly often because of their inability to obtain their drug. This has absolutely nothing to do with addiction. There are several drugs which people may become addicted to, like marijuana, but which do not invoke drug dependence.
(Update: It is worth noting that there is a behavior that is noted as pseudo-addiction, and is defined as exhibiting addiction-like behaviors toward a drug. That is, a patient is obsessed with getting more of a drug, but not because they’re addicted. This is seen often in pain patients whose pain is not being adequately treated. Trust me, if you were in severe pain your entire life, you’d probably be pretty obsessed with obtaining pain relief. This can appear to be addiction, and, very unfortunately, many pain patients which exhibit this behavior will be marked as drug seeking and are doomed to suffer.)
So what makes people become addicted to something? No one really knows. As it is a psychological disorder, it’s hard to pin it down. Anyone can become addicted to anything at any point. The unfortunate thing is that most drugs that people are interested in developing an addiction to tend to be either controlled or illegal. This means they have to turn to the black market, and become criminals in the process. So how many people become addicts? Clinically, for people who are taking prescribed medication as it was prescribed, less than 1% of all patients become addicted. This means that, out of 1,000 pain patients, around 0-10 of those patients will experience addiction. Some people think this is unacceptable, and that it’s better to let those 990-1000 patients simply suffer.
For those of you who aren’t in pain, good for you, that’s a reasonable position to take. Pain is transient, you can tough it out, right? Except when it isn’t transient. Millions of people, including me, are in chronic pain. That means we’re in pain every minute of every day. There are many treatments for many conditions that cause this, but for millions of people the only answer to their pain is to be on opioids long-term. People have a stigma about this because they only time they hear about opioids is when someone ODs on heroin. Because of the <1% of patients, the other >90% have to suffer more. Doctors are terrified to prescribe opioids because of their psychological effects, so they’d rather not treat anyone at all. I think this is stupid, and I don’t understand how, as someone who has promised to “limit suffering,” they can do this. Sure, opioids make you feel good, and in our society that is a Bad Thing™, but for the rest of us who need them to live, please, I implore you, pull your heads out of your asses.