Hallucinogens
are drugs that cause altered states of perception and feelings. They can
produce unexpected flashbacks of altered states of mind. Some are natural
substances such as mescaline and psilocybin that come from plants (cactus
and mushrooms. Others are manufactured such as LSD which is made from
lysergic acid which is found in a fungus that grows on rye and other
grains.
LSD binds to and activates a specific receptor for the
neurotransmitter serotonin, which normally binds to and activates its
receptors and then is re-absorbed into the neuron that released it. LSD
binds very tightly to the serotonin receptor, causing a greater than normal
activation of the receptor.
Because serotonin plays many important roles in the brain,
when LSD activates its receptors users experience a widespread effects that
include mood swings, altered perceptions, delusions, and visual
hallucinations.
MDMA (ecstasy) and PCP, while not a true hallucinogen, are
often classified as this type because of they change the way how the brain
perceives time, reality, and surrounding events. Users can hear voices, see
images, and feel sensations that do not exist. PCP and MDMA are both
physically addicting.
PCP interferes with the functioning of the neurotransmitter
glutamate, which is found in neurons throughout the brain. Like many other
drugs, it also causes dopamine to be released from neurons into the
synapse. PCB can cause effects that mimic the primary symptoms of
schizophrenia, such as delusions and mental turmoil. People that use PCP
for long periods of time have memory loss and speech difficulties.
MDMA, which is similar in structure to methamphetamine,
causes serotonin and dopamine to be released from neurons in greater amounts
than normal. Once released, these can excessively activate these
receptors. MDMA can destroy serotonin-containing neurons causing
hallucinations, confusion, depression, sleep problems, drug craving, severe
anxiety, and paranoia.