The War in Your Brain - Understanding Drug Tolerance and Addiction

One neglected battlefield of the War on Drugs is the one that occurs inside an addict's head. This is because the physiological mechanisms responsible for our survival in the event of chemical infiltration are a seemingly double edged sword that may be more dangerous than beneficial in the long run. This survival mechanism is called drug tolerance - an addict's most wearisome enemy - but not for the reasons you might think.

In simple terms, tolerance is the body's way of developing a resistance to a particular drug. This resistance is generated when changes prompted by drug use are made to nerve cells in the brain and central nervous system. The sequence of events is as follows:

1. Use of drug stimulates release of dopamine (or another neurotransmitter) from nerve cell
2. Dopamine binds with the next receptor in the neuronal circuit
3. Chemical substance (cocaine, etc) interferes with the neurotransmission process
4. Euphoria or similar sensation is felt by user
5. With repeated use, receptors are altered to impede the transmission of dopamine and mitigate drug effects
6. With altered receptor state user finds it more difficult to "get high"
7. User increases dosage
8. Brain increases receptor impedance

The cycle of addiction is now fully in place. What we see here is that the protective process of tolerance is actually backfiring. With more drug use comes increased tolerance, which requires increased drug use in order to overcome. The body's protective mechanisms are forcing the addict to consume more and more of the substance, thereby solidifying their behavior and causing a subsequent rise in the number and nature of changes made to nerve cells and other functions in the brain.

Some addicts have adapted to the processes of tolerance by switching drug types. For instance, a drug abuser who can no longer "get high" from methamphetamine might switch to cocaine. Or a person addicted to opiates might switch to benzodiazepine in the event they find that their drug of choice no longer works for them.

Other addicts have even stopped using for several weeks only to deliberately return to using again when they feel their tolerance has been decreased.

But whatever strategy addicts use, tolerance always meets them head-on. And with continued use, tolerance leads to addiction to each new persistently abused substance. Unfortunately, many substances of abuse are dangerous to suddenly stop using - especially if cessation is prompted by tolerance. This means that the substance must be stepped-down gradually, even if the user doesn't obtain a euphoric high from the doses.

Both the process of tolerance and addiction essentially amount to primitive survival mechanisms backfiring. With repeated use of a substance this condition can happen to anyone; we are all built the same. It's unfortunate that addicts cannot recognize the fact that when they find it increasingly more difficult to get high, this is the body's way of naturally stemming the tide of drug use. But because an addict can override this natural protection, things can - and do - progress to a terminal point for many people.

If you find yourself taking more of a drug or drinking more simply because the same amount doesn't get you high anymore, you're treading a dangerous path to tolerance, then dependence, and finally outright addiction. Listen to what your body is trying to tell you, and stop now before it's too late.