What causes psychosis?

There has been a lot in the news lately about people suffering from psychotic episodes. Recently, a man, whom many thought was under the influence of bath salts, took off his clothes and chewed off the face of a homeless man. Toxicology reports denied him being under the influence of bath salts but confirmed marijuana being in his system. Another news event broadcasted the sad episode of a Jet Blue pilot who started behaving in an erratic way,  talking in religion themes and Iraq and the end of the world. He had to be restrained by flight attendants and passengers on the airplane before the plane making an emergency landing.
What causes psychosis? Is this a biochemical or genetic condition? Are there environmental factors or health habits that contribute to it? What can be done to treat or prevent the condition from happening?

The definition of psychosis found in Wikepedia is: refers to an abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a “loss of contact with reality”. People suffering from psychosis are described as psychotic. Psychosis is given to the more severe forms of psychiatric disorder, during which hallucinations and delusions and impaired insight may occur.
The two major categories of mental illnesses we often associate with psychosis are the mood disorders such as Depression and Bipolar Disorder as its substypes as well as Schizophrenia. In Bipolar Disorder these psychotic episodes occur during the manic phases of the illness. There are other condtions that can cause psychosis. People under the influence of psychostimulants such as Ritalin or Cocaine or Methamphetamine may become psychotic, particularly if predisposed genetically to psychosis. Lately, in the news we have heard about people acting strangely under the influence of Bath Salts. And very recently, marijuana may have been a factor in the face eating incident.
In later years there is another cause that is being more and more recognized. Children who experience trauma may exhibit psychotic symptoms, particularly hearing voices. These children often don’t meet criteria for drug usage, mood disorders like Bipolar illness or Schizophrenia.
I personally have concerns about Marijuana. Many people would like to think that Marijuana is harmless. It is used for some chronic health issues like pain control and lack of appetite. Unfortunately, it is also being used inappropriately. I have had patients who come see me for an Anxiety problem who have complained to me that pot makes them anxious or even “crazy”. Pot will do this in people that are genetically predisposed toward psychosis. I once saw a promising young 18 year old man deterioriate and contract Schizophrenia, and Marijuana was believed to be the major culprit.

What is the treatment? It depends on the cause. If it is Bipolar Disorder, mood stabilizers and psychotherapy are the treatment of choice. Schizophrenia will probably require antipsychotic medication. If psychostimulants brought it on, they probably will need to be discontinued. For children with the history of trauma, medications may not be as effective as psychotherapy. Although many may find some benefit from both. Finally, the cause of the psychosis of the Jet Blue pilot was found to be the lack of sleep. I can’t emphasize enough the role of sleep in good mental health. I teach all my patients sleep hygiene who come to see me. A brain cannot heal or function optimally without a good nights sleep. What is the optimal amount? About 7-8 hours for most people.