Methamphetamine Changes the Brain

Usually neurons recycle dopamine. But methamphetamine is able to fool neurons into taking it up just like they would dopamine. Once inside a neuron, methamphetamine causes that neuron to release lots of dopamine. All this dopamine causes the person to feel an extra sense of pleasure that can last all day. But eventually these pleasurable effects stop. They are followed by unpleasant feelings called a “crash” that often lead a person to use more of the drug. If a person continues to use methamphetamine, they will have a difficult time feeling pleasure from anything. Imagine no longer enjoying your favourite food or an afternoon with your friends.

Because it is similar to dopamine, methamphetamine can change the function of any neuron that contains dopamine. And if this weren’t enough, methamphetamine can also affect neurons that contain two other neurotransmitters called serotonin and norepinephrine. All of this means that methamphetamine can change how lots of things in the brain and the body work. Even small amounts of methamphetamine can cause a person to be more awake and active, lose their appetite, and become irritable and aggressive. Methamphetamine also causes a person’s blood preassure to increase and their heart to beat faster.

Scientists are using brain imaging techniques, like position emission tomography (called PET for short), to study the brains of human methamphetamine users. They have discovered that even three years after long-time methamphetamine users had quit using the drug, their dopamine neurons were still damaged. Scientists don’t know yet whether this damage is permanent, but this research shows that changes in the brain from methamphetamine use can last a long time. Research with animals has shown that the drug methamphetamine can also damage neurons that contain serotonin. This damage also continues long after the drug use is stopped.

These changes in dopamine and serotonin neurons may explain some of the effects of methamphetamine. If a person uses methamphetamine for a long time, they may become paranoid. They may also hear and see things that aren’t there. These are called hallucinations. Because methamphetamine causes big increases in blood pressure, someone using it for a long time may also have permanent damage to blood vessels in the brain. This can lead to strokes caused by bleeding in the brain.

Researchers are only beginning to understand how methamphetamine acts in the brain and body. When they learn more about how methamphetamine causes its effects, they may be able to develop treatments that prevent or reverse the damage this drug can cause.

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