Series: The Toll Of Meth

THE NEUROSCIENCE OF METH -- FROM PLEASURE TO PARANOIA, DRUG'S EFFECTS
EXPLAINED THROUGH BRAIN CHEMISTRY

From a neurological perspective, it's easy to understand the appeal
of methamphetamine.

As the drug enters the bloodstream and begins to affect the brain, it
triggers a neurological system designed to give pleasure for certain
behaviors. The feeling is familiar and, in its own bizarre way, even
natural. For a while.

People start using meth to feel good. They later use meth just to
feel better, ironically trying to combat psychological problems with
the very drug that caused the problems.

And eventually, almost all frequent meth users experience some
physical and mental problems: Weight loss, skin lesions, rotting
teeth, paranoia, sexual dysfunction, hallucinations, twitching and
lethargy are among the known effects of the drug.

Because of their mental state, meth users also are more likely to
have violent encounters with people they know, strangers and law
enforcement, and are more likely to hurt themselves.

It all begins, as do almost all our emotions and sensations, with
chemical reactions in the brain. Whether pleasure, excitement or
fear, those sensations usually are the brain's natural reactions to
natural stimulation.

Off balance But when those feelings are triggered unnaturally, the
brain is thrown off balance and sometimes tries to compensate in
harmful ways, explained Dr. Richard Rawson, a professor in the
department of psychiatry at UCLA.

As a result, the same drug that once caused excitement and a sense of
clarity later causes lethargy and paranoia. What once brought
happiness eventually brings a condition called anhedonia, or the
inability to experience pleasure naturally. The stimulant that keeps
users awake for almost a week eventually causes them to sleep for days.

Users, of course, do not crave the drug because of the bad
consequences, which do not emerge immediately. They initially take
the drug because it feels good.

"Methamphetamine creates a release of dopamine in the reward centers
of the brain that allows you to feel pleasure," Rawson said about the
drug's immediate effect.

Dopamine is a chemical that acts as a neurotransmitter, which relays
nerve impulses to muscles, glands or other nerves. It also is called
the brain's primary pleasure chemical because of its role in the
reward center, a part of the brain that awards pleasant feelings for
certain behaviors, such as eating or sex, which are necessary for
survival and procreation.

Meth triggers a huge release of dopamine in the brain, magnifying
about 10 times the pleasure it would normally deliver, Rawson said.
Everyday events suddenly become exciting, and the world is suddenly a
much more interesting place for the new user. The sensation can last
eight to 12 hours, Rawson said.

Damage sets in The brain's level of dopamine returns to normal as the
drug wears off. Rawson said the trouble begins when the user tries to
repeat that sensation again and again, draining the brain's dopamine
reserve and damaging the body's ability to produce more.

Explaining it numerically, Rawson said to imagine a normal brain
operating with a dopamine level of 10, while a frequent meth user's
brain has a dopamine level of 8. Meth users in this state experience
anhedonia, and they need another boost of dopamine just to feel
normal again, Rawson said.

"You feel depressed, fatigued or just sluggish," he said. "So you
need methamphetamine to kick in your dopamine again. You've created
this vicious circle."

With the body's dopamine level diminished, a dose of meth does not
deliver the same rush as the first use.

Addicts sometimes say they use the drug just to bring their energy up
to a functioning level, and Rawson said some longtime users have told
him the drug has lost all its pleasurable effect. They use it only
for Pavlovian reasons, going through the motions from force of habit, he said.

But as some parts of the brain become numb to the once-pleasurable
effects of methamphetamine, the temporal lobe actually becomes more
sensitive to the drug, Rawson said.

Eventually, psychotic An overstimulated temporal lobe can trigger a
psychosis such as hallucinations or delusions. About two-thirds of
meth users experience some type of psychosis, and Rawson said some
become so sensitive to the drug that hallucinations become a regular
part of its use.

In a combination that sometimes has tragic results, hallucinations
can be accompanied by paranoia caused by the drug's effect on the
amygdala, an almond-shaped part of the brain that has a large role in
expressing fear, rage and aggression.

When stimulated, the amygdala creates a heightened sense of fear and
anxiety, prompting a fight-or-flight response important for survival.

Triggering the reaction unnaturally creates an unfocused anxiety in
meth users, Rawson said.

"You have this feeling of anxiety produced by methamphetamine, and
you don't know what it's about," he said. "The feeling to the user
is, 'Something's wrong, and I'm in danger. Why I'm in danger, I don't
know.' It's sort of a feeling detached from cognitive reasoning.
You're not afraid for any reason, it's just that the drug has
stimulated your emotional anxiety."

Rawson said the drug's effect on the brain leads to paranoia in about
80 percent of meth users and often shows up within the first few
months of using.

"In many cases, that'll be the cause of some of the violence
associated with methamphetamine," he said.

Prone to violence As an example, he said, if a man comes home from
work and his wife has gone shopping, he may imagine she is cheating
on him, so he beats her when she returns. In many cases, paranoia and
delusions have led to homicide, he said.

Methamphetamine also suppresses brain functions found in the
prefrontal cortex and the limbic system.

The prefrontal cortex is the more evolved part of the brain that
controls rational thought and overrides impulsive behavior. The
limbic system, sometimes referred to as the reptilian brain, controls
emotions, hunger, thirst, sleep and other biological functions.

The stimulation of the drug also causes an increase in sexual desire
in men and women, Rawson said.

"All the data we've seen on this shows people who take
methamphetamine have more sex than those who don't," he said. "The
cops that used to go out and busts labs, they'd say universally there
was pornography and even people videotaping themselves."

But the drug also causes delayed ejaculation in men, which Rawson
said can lead frustrated men to compensate with aggressive, bizarre
and even violent sexual behavior. After excessive drug use, however,
some male meth users have experienced sexual dysfunction, he said.

Meth mouth Some chemical precursors used to make the drug can excrete
through perspiration and damage the skin, but Rawson said most of the
sores that appear on some meth addicts are self-inflicted.

The drug restricts blood vessels in the skin, which creates a
tingling or itchy feeling. Meth users who are fidgety, sleepless and
subject to hallucinations will scratch incessantly at the itch,
sometimes believing they are feeling bugs crawling under their skin
and picking their flesh raw until they leave open wounds.

"For some reason, men tend to scratch their arms and torsos, and
women their faces," he said.

Finally, the drug can cause what has been called meth mouth, or a
rapid decay of teeth. A combination of the drug's acidic nature and
dry mouth caused by a lack of saliva leaves teeth vulnerable to decay.

Combined with poor dental hygiene and an addict's unhealthy diet of
sweets, sustained abuse creates what dentists have called a perfect
storm of oral problems, Rawson said.