LONG TERM EFFECTS OF

DRUGS ON THE BRAIN

1) What are some of the ways that drugs cause long-term changes in the brain?

A. The continued use of drugs may cause the brain to become resistant to the effects of the drug (tolerance).

Drug Tolerance

  2) How does the brain adapt to the presence of drugs?

The brain adapts to the presence of drugs by developing tolerance for the drug.

Tolerance may develop because:

the body may become more efficient at eliminating the chemical from the body

the cells of the body and brain become less responsive to the effect of the drug (decrease in number of recepetors

Control Addicted

Dopamine D2 Receptors are Decreased by Addiction

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Cocaine

Alcohol

Heroin

Meth

1) What are some of the ways that drugs cause long-term

changes in the brain?

A. The continued use of drugs may cause the brain to become resistant to the effects of the drug (tolerance).

B. Some drugs, such as alcohol and MDMA, can kill brain cells.

Why are large amounts of alcohol bad for the brain?

In large doses, alcohol kills neurons in 2 specific brain areas:

the mammillary bodies (important for memory) the cerebral cortex (controls mental functions)

Alcohol and the Brain

How does MDMA (ecstasy) affect the brain?

It kills neurons that produce serotonin

Serotonin = a neurotransmitter involved in regulating appetite, sleep, emotions.

Ecstasy and the Brain

1) What are some of the ways that drugs cause long-term

changes in the brain?

A. The continued use of drugs may cause the brain to become resistant to the effects of the drug (tolerance).

B. Some drugs, such as alcohol and MDMA, can kill brain cells.

C. Cocaine can cause the activity level of the brain to decrease for a long period of time after drug use is stopped.

How does cocaine affect the brain?

  It reduces glucose metabolism up to

three months after the last use of the drug

This indicates that the neurons of cocaine addicts are less active 3 months after they have stopped using the drug

Cocaine and the Brain

3) How may the abuse of drugs relate to the plasticity of the

brain? Plasticity means that the brain can modify

connections (synapses) in response to experiences.

Drugs that cause neuronal death can decrease the plasticity of the brain because neurons are not present to form new connections and because existing connections are lost.

Brain plasticity

4) What are some problems that scientists have when they investigate the effects of drugs

on the brain? Many drug abusers abuse more than one

drug.

Drugs taken in combination may have different effects.

Also, many drug abusers have other medical conditions

Summary: Drugs Change Brain Chemistry! Long term drug abuse and addiction can lead to

changes in the brain’s anatomy and chemistry Loss of neurons in hippocampus results in memory

lossDecrease in glucose metabolism results in a

reduction of the brain’s processing abilities

These changes in the brain cause drug addicts to loose the ability to control their drug use