The Brain's Response to
Hallucinogens

Hallucinogens cause people to experience - you guessed it - hallucinations, imagined experiences that seem real. The word "hallucinate" comes from Latin words meaning, "to wander in the mind."

No wonder some people refer to hallucinating as tripping.

The "trips" caused by hallucinogens can last for hours. Parts of these trips can feel really good, and other parts can feel really terrible.

Hallucinogens powerfully affect the brain, distorting the way our five senses work and changing our impressions of time and space. People who use these drugs a lot may have a hard time concentrating, communicating, or telling the difference between reality and illusion.

Where Do Hallucinogens Come From?

Some hallucinogens can be found in plants. Mescaline comes from a cactus called peyote. And certain mushrooms, also known as magic mushrooms, are hallucinogens.

But many hallucinogens are chemicals that don't occur in nature. Some examples are:

• LSD, also called acid;
• MDA, an amphetamine;
• MDMA, an amphetamine, called ecstasy (no not ecstasy);
• PCP (phencyclidine), often called angel dust, embalming fluid, supergrass, killer weed, and rocket fuel.

How Hallucinogens Affect Your Senses

Your brain controls all of your perceptions -- the way you see, hear, smell, taste, and feel. How does your brain communicate with the rest of your body? Chemical messengers transmit information from nerve cell to nerve cell in the body and the brain. Messages are constantly being sent back and forth with amazing speed.

Your nerve cells are called neurons, and their chemical messengers are called neurotransmitters. When neurotransmitters attach to special places on nerve cells (called receptors), they cause changes in the nerve cells.

This communication system can be disrupted by chemicals like hallucinogens, and the results are changes in the way you sense the world around you.

A Recent Discovery

MDMA and MDA cause neurons to release a neurotransmitter called serotonin. Serotonin is important to many types of nerve cells, including cells that receive sensory information and cells that control sleeping and emotions. The released serotonin can over activate serotonin receptors. In animals, MDMA and MDA have been shown to damage and destroy nerve fibres of neurons that contain serotonin. This can be a big problem, because serotonin neurons have a role in so many things, such as mood, sleep, and control of heart rate.

Scientists have recently found that the damaged serotonin neurons can regrow their fibres, but the fibres don't grow back normally. The fibres may regrow into brain areas where they don't normally grow, but not into other brain areas where they should be located. The new growth patterns may cause changes in mood, learning, or memory.

Actions of PCP in the Brain

PCP prevents the actions normally caused when a neurotransmitter, called glutamate, attaches to its receptor in the brain. It also disrupts the actions of other neurotransmitters.

This drug's effects are very unpredictable. For example, it may make some people hallucinate and become aggressive, while others may become drowsy and passive. It is also addictive.