Hallucinations: From the Supernatural to the Scientific

For most of human history, hallucinations have been a mystery of the mind. The only way they could be explained were through spirits, demons, or other supernatural forces. However, modern science has made giant steps over the past century and scientists are finally being able to explain how our brain produces hallucinations. Each year, more is learned mostly due to the modern innovations of technology capable of mapping the brain and detecting the effects of different neurotransmitters. (Torgenrud, 2005)

In general, hallucinations are sensory perceptions that occur while a person is conscious, but there is no actual external stimulus. Hallucinations generally occur "when brain metabolism is altered from its normal level" (Hallucinations, 2001). This may happen in many different ways, such as through high fevers, brain tumors, strokes, hallucinogenic drugs, withdrawal from hallucinogenic drugs, and other brain damaging ailments. Hallucinations may occur during high physical stress, as well as times of extremely strong emotional stress. The emotional stress is usually caused by either severe trauma or by the pain of losing a close relative or friend. In addition to being caused by extreme physical or emotional stress, hallucinations often result from psychotic disorders such as schizophrenia, in which the affected person may hear voices or see things that are not actually there. (Ford-Martin, 2001)

Most of what actually causes hallucinations on a neurological level is relatively unknown. By studying the effects of hallucinogenic drugs on the functioning capacity of the brain, scientists are beginning to learn what goes on in each brain synapse that could cause hallucinations. Hallucinogens are drugs that "cause altered states of perception" (Mind Over Matter, 2003). While hallucinogens can be found in natural substances such as mescaline and psilocybin, they are more commonly natural substances that have been chemically altered. Both LSD and MDMA (ecstasy) affect the levels of serotonin in a brain's synapse. (Mind Over Matter, 2003)

In particular, LSD attaches itself to serotonin receptors in neurons and activates them. But, instead of the immediate reuptake that would occur if it had been serotonin that had bonded to the receptor, there is a "greater than normal activation of the receptor" (Mind Over Matter, 2003). This causes the ion channel to be open for an excess period of time, which results in an over stimulation of the neurons in certain areas of the brain. The areas most directly related to hallucinations are the temporal lobe, which contains the auditory cortex, and the occipital lobe, which contains the visual cortex (Mind Over Matter, 2003). If these areas are over stimulated to a certain degree, visual or auditory hallucinations will result (Hallucinations, 2001).

MDMA can produce similar effects on the brain as LSD; however, how these effects are accomplished is slightly different. MDMA affects the amount of serotonin released into the synaptic cleft dividing two neurons, thereby dramatically increasing the amount of serotonin neurotransmitters released that will bind to their appropriate receptors (Mind Over Matter, 2003). With so many extra neurotransmitters being released in each synapse, an over stimulation of certain brain regions will occur.

However, the most interesting effect of MDMA does not occur during the use of LSD. MDMA causes excess dopamine to be released at brain synapses. While no conclusions may be drawn from this information, it provides an intriguing possibility involving the psychotic disorder schizophrenia. "A leading neurobiological hypothesis," states Gulli and Rosick, both of which are accomplished scholars with a MD, MPH, BS, and DO between themselves, "looks at the connection between the disease and excessive levels of dopamine, a chemical (neurotransmitter) that transmits signals in the brain" (2005). More support for this hypothesis comes from the fact that MDMA is not the only drug that triggers excess dopamine to be released, which can result in hallucinations

The presence of Phencyclidine (PCP) also affects neurotransmitters, most notably glutamate and dopamine. While PCP is not actually a hallucinogen, it may act similar to a hallucinogen on the neurological level. Primarily, it affects glutamate, which in excess quantities commonly over stimulates the brain. As a secondary effect, PCP causes excess dopamine to be released. If large enough doses of PCP are taken, then hallucinations will occur sometimes. The Cleveland Clinic also points out that "PCP can also cause effects that mimic the primary symptoms of schizophrenia, such as delusions and mental turmoil" (Mind Over Matter). This implies not only the importance of dopamine to hallucinations, but also other neurotransmitters as well.

While dopamine may be related to hallucinations involving schizophrenia, it appears that serotonin may be the neurotransmitter closely related to drug withdrawal related hallucinations. Excess use of drugs such as "MDMA can damage and destroy serotonin containing neurons" (Mind Over Matter). A serious lack of serotonin can bring about different forms of hallucinations as a result of its side effects. One main function of serotonin is to help regulate sleep. A lack of serotonin will chronically affect a person's sleep, and with no sleep comes fatigue (Torgenrud). When too fatigued from a serious lack of sleep, it is possible that a person may have hallucinations as a result of severe physical stress. One can speculate that such hallucinations may result from a significant lack of serotonin.

Kagan's journal titled "Hallucinogens" summarizes our current knowledge on the subject matter: "How...hallucinogens produce these bizarre effects remains unknown" (Kagan, 1998). While this is true, each year more and more is discovered to help uncover the psychological mystery of hallucinations. The "educated" no longer turn to the supernatural as a scapegoat answer. Scientists know what tends to cause hallucinations, but the causes are so widespread that new discoveries are being made every year. It appears that neurotransmitters, particularly dopamine and serotonin, are the key to hallucinations, but questions still remain. It is still unclear exactly what some neurotransmitters' functions are and if there are others yet to be discovered. It is safe to say that tremendous achievements have been made over the past years providing an adequate answer to replace the previous supernatural one. But, this field is relatively new and the future is sure to hold more answers to this conundrum of modern science.

References

Cleveland Clinic. (2003). Mind Over Matter Teacher's Guide: Hallucinations, Retrieved October 19, 2005 from

http://www.clevelandclinic.org/health/health-info/docs/0900/0929.asp?index=5580&src=news

Ford-Martin, P. A. (2001). "Hallucinations." The Gale Encyclopedia of Medicine. Second Edition. Longe, J. L., Editor. 5 vols. Farmington Hills, MI: Thomson Gale.

Gulli, L. F. and Rosick, E. R. (2005). "Schizophrenia." The Gale Encyclopedia of Genetic Disorders,Second Edition. Brigham Narins, Editor. Farmington Hills, MI: Thomson Gale.

Hallucinations, (2001) Retrieved October 20, 2005 from

http://www.rwjhamilton.org/Atoz/encyclopedia/article/003258.asp

Kagan, J. (Executive Ed.). (1998). "Hallucinogens." The Gale Encyclopedia of Childhood and Adolescence. Gall, S. B., Managing Ed. Detroit, MI: Thomson Gale.

Torgenrud, C. (2005, September). Psychology. Unit 2:1 Neuroscience and Behavior. York School, Monterey, CA. Retrieved from http://www1.york.org/psych/2Neurosci1.htm