Meth & The Brain

To put the brain and the flow of neurotransmitters when using meth into something we can understand, let's use an analogy of a bathtub and water. Meth either causes your bathtub to overflow, or prevents you from mopping up the water that's already overflowed onto the floor, or both. Now let's take this bathtub analogy one step further. Your bathtub is overflowing, your mop doesn't work, so what's the next thing you'd do? That's right, you'd turn off the water. But that's the other thing that meth does - it blocks you from doing that as well.

Basically, meth is confusing the brain by mimicking certain neurotransmitters and causes a series of events that creates a dangerous chemical imbalance within the brain, resulting in both nerve cell death and nerve cell structural change. Normally, the brain can employ different safety mechanisms to protect against imbalances of neurochemicals, but meth interferes with these safety mechanisms. And shutting down these safety mechanisms can ultimately result in nerve cell death.

So by releasing these neurotransmitters into the gap between nerve endings, the "alerting and stimulating" effect comes from the norepinephrine, and the accompanying schizophrenia psychosis takes place because of the abnormal release of dopamine.

The point here is that when you use meth, you're putting your entire system into a highly artificial state that it wasn't meant to be in. And what's really important is that if you do it long enough, that becomes the new version of "normal." And that means that if you want to simply feel normal from then on, you have to induce it artificially with more meth because you've "raised the bar" so to speak for what the brain requires to feel normal.

And that's why when you come down from meth, or your system starts to "catch on" to the idea that it's not getting anymore meth, one of the first things you feel is incredibly depressed because meth has robbed you of your ability to experience pleasure and comfort "normally." In fact, when you're in recovery from meth, one of your goals is to "re-learn" how to experience pleasure normally again. Every recovery from addiction involves that process to a degree, but with methamphetamine, it seems like it's one of the major challenges during a successful rehabilitation.

When you look at the picture of the brain on the opening page of this section, you don't need to be a neurosurgeon to see that there are some profound changes going on in the brain of someone using methamphetamine. There's still a great deal to be learned about exactly how meth affects the brain of users and the long-term consequences, but there are a few facts that do seem confirmed.

The very first high-resolution M.R.I. (Magnetic Resonance Imaging) study of methamphetamine addicts has shown what an expert on brain mapping describes as ''a forest fire of brain damage.'' Dr. Paul Thompson, an expert on brain mapping at the University of California, Los Angeles said ''We expected some brain changes but didn't expect so much tissue to be destroyed.''

The image, which was published in the June 30, 2005 issue of "The Journal of Neuroscience," shows the brain's surface and deeper limbic system. The limbic region, specifically the striatum, is involved in drug craving, reward-linked motivation, mood and emotion. It lost 11% of its tissue. It would appear that either these cells sustain more persistent damage or they are in fact, gone.

So it's little wonder that such addicts with this kind of tissue loss would be depressed, anxious and unable to concentrate. Many also suffer from what appears to be "anhedonia," which is a scientific term to describe "an absence of pleasure," or in short, the reduced capacity to actually experience pleasure that can last periods of years.

Obviously, this not only has a catastrophic effect on the person's psychology, it also dramatically affects how we go about "rehabilitating" that person and provide proper treatment and aftercare.

The blood-brain barrier (abbreviated BBB, not to be confused with the blood-cerebrospinal fluid barrier, a function of the choroid plexus) is a membrane that controls the passage of substances from the blood into the central nervous system. It is a physical barrier between the local blood vessels and most parts of the central nervous system itself, and stops many substances from traveling across it. Alcohol, amphetamines, certain heavy metals as well as some hormones, including insulin and leptin, can cross the blood-brain barrier.

Methamphetamine is lipid (the primary structural material of cells) soluble (can be dissolved) and after absorption it distributes into the brain, lung, and kidneys. Amphetamine crosses the blood brain barrier readily. Brain levels reach about 10 times the blood levels, which accounts for the relatively pronounced central nervous system effect.

The brain's center for making new memories, the hippocampus, lost 8% of its tissue. This amount of loss is is comparable to brain deficits in early Alzheimer's patients. As a result, the methamphetamine addicts fared significantly worse on memory tests than healthy people the same age. The point here is that although the brain can rehabilitate a portion of the damage over time, it would seem that some meth addicts will be to some degree, permanently impaired from a functional standpoint until we learn how to rehabilitate all the damaged areas.

Having said that, it should be noted that almost on a weekly basis, more is being learned about the incredible "elasticity" of the human brain and how to induce that quality on a more proactive basis. "Elasticity" refers to the brain's ability to repair damage, rehabilitate itself, and "re-learn" how to perform simple and complex tasks. That's good news for long-term meth users, as well as anyone else who has suffered some type of neurological damage or impairment.

On the next and final page of this section, we're going to take a look at some of the brain-related effects of meth addiction that both complicate and frustrate attempts at treatment and rehabilitation.