Schizophrenia is the most common form of major psychosis; it is estimated that over 45 million people are affected worldwide. The pathogenesis of schizophrenia is not fully understood but there is some evidence suggesting that the basis of this disease is disruption to the balance of chemical messengers and nerve pathways in the brain. Schizophrenia can sometimes be caused by heavy use of halluciogenic drugs, especially LSD; but it appears that one has to have a predisposition towards developing schizophrenia for this to occur. There is also some evidence suggesting that people suffering schizophrenia but responding to treatment can have an episode as a result of use of LSD. Methamphetamine and PCP also mimic the symptoms of schizophrenia, and can trigger ongoing symptoms of schizophrenia in those who are vulnerable. There is also some evidence that marijuana usage can be a contributing trigger to schizophrenia in vulnerable individuals.
The first schizophrenic episode typically occurs between the ages of fifteen and thirty. Men typically develop the symptoms five to ten years earlier than women. Relapse rates without treatment are high and without prompt and assertive treatment, permanent disability can result. The symptoms of the illness tend to improve later in life corresponding to decreases in the neurotransmitter Dopamine. Schizophrenia is incurable but can be treated with [antipsychotic drugs]?. These drugs can have many unpleasant side effects; many patients may stop taking their medication as a result of extrapyramidal side-effects (EPSE), a variety of movement disorders described at [[here]].
Symptoms of schizophrenia often overlap with other "major mental illnesses", particularly mood disorders or obsessive compulsive disorder. The term "schizoaffective disorder" is used for situations where an individual has the distinct "thought disorder" symptoms of schizophrenia, combined with "mood disorder" symptoms usually associated with Bipolar Disorder or depression.
In the 60's there was a movement called anti-psychiatry? that claimed that psychiatric patients are not ill and that they are just individuals that are misfit in society, and therefore put into asylums. Whilst there may have been some truth to this assessment with regards to mental illness in general, anthropological studies indicate that roughly equivalent percentages of people in a variety of cultures, some very different to modern Western culture, develop a disease recognised by that culture as such, with similar symptoms to schizophrenia, and subsequent medical examination of afflicted individuals show similar physical abnormalities as schizophrenics.
Researchers into shamanism have speculated that in some cultures schizophrenia or related conditions may predispose an individual to becoming a shaman.
The 1976 book The Origin of Consciousness in the Breakdown of the Bicameral Mind, by psychologist Julian Jaynes proposed that until the beginnings of historic times schizophrenia or a closely similar condition was the normal human consciousness; a "bicameral mind" in which a normal state of low affect suitable for routine activities would be interrupted in moments of crisis by "mysterious voices" giving instructions, which early people characterized as interventions from the gods. This theory was briefly controversial but continued work has not provided additional support.