Drugs Alter The Brain

All drugs of abuse activate the dopamine system in the reward pathway.

Dr. Glen Hanson

A quick introduction to the many drugs of abuse and their effects on the body.

Within seconds of entering the body, drugs cause dramatic changes to synapses in the brain. By bypassing the five senses and directly activating the brain's reward circuitry fast and hard, drugs can cause a jolt of intense pleasure.

Meth (green) fools the cell into dumping lots of dopamine (red) into the synapse, causing a surge of exhilaration.

Synapse

Dopamine

Meth

Receptors

Drugs of abuse affect the brain in such a dramatic way that the brain must try to adapt. One way the brain compensates is to reduce the number of dopamine receptors at the synapse. As a result, after the user has "come down", they will need more of the drug next time they want to get high. This response is commonly referred to as "tolerance."

Normal

Meth Abuser

Red indicates the presence of dopamine receptors. The meth abuser has severely reduced receptor levels. Other drugs such as alcohol, cocaine and heroin have been shown to have this same effect.

Take a look inside the brains of mice on drugs. Learn how various drugs disrupt the synapse to make the user feel "high."

The faster a drug is delivered to the brain, the more likely it is to be addicting.

Take an in-depth look at one of the brain's dopamine synapses, then add methamphetamine and watch what happens.

As the brain continues to adapt to the presence of the drug, regions outside of the reward pathway are also affected. Brain regions responsible for judgment, learning and memory begin to physically change or become "hard-wired."

Once this happens, drug-seeking behavior becomes driven by habit, almost reflex. This is how a drug user becomes transformed into a drug addict.

Meth Addict

Normal

Neurons outside of the reward pathway in meth-addicted brains have longer, thicker dendrites than those from a non-addicted brain.

Click the mouse button below to morph the PET scan between a normal brain and the brain of a former cocaine addict.

Click here to morph the brain.

The reward pathway isn't the brain's only pathway. Learn more about other pathways in the brain and how drugs affect them.

Drugs can affect the brain and the body so dramatically that an overly large dose can actually kill the user. To learn more about how you can OD, follow the link below.

PET scans are pictures of brain slices. PET scan images reveal compelling proof of dramatic long-term and short-term changes from drug usage.