Psychosis is the name used in psychiatry for a number of conditions. People who suffer from psychosis are said to be psychotic. Usually, psychotic people lose touch with reality, they have trouble telling what is real and what is not. It is an extreme kind of altered state of consciousness.

The word psychosis has two parts. The first part comes from psyche, which means soul in Ancient Greek. The second part is the ending '-osis', which means illness or unnatural condition. So literally, psychosis means unnatural condition of the soul.

People with psychosis may have hallucinations, which means they can experience things that are not really there. They may also have delusions, which are fixed beliefs and ideas that are usually false. Sometimes their personality changes, and they cannot think straight. Some of these thoughts may be paranoid. Not every psychotic person has all of these problems.

Because of these, psychotics often act in strange ways, which also makes it difficult for them to live a normal life as part of  society. They often have trouble with making friends, as most people do not understand them.

Psychosis can affect people to different levels. Some people can continue with mostly normal lives, while other people will need medical help.

About 1 percent of people suffer from psychosis during their lives.

There are many things that can make someone seem psychotic. These include poisons, drugs, diseases of the nervous system, and other illnesses. For this reason, some people use the image of a fever of the central nervous system to talk about psychosis - a serious illness that may not have a very detailed explanation.

Many people have gone through unusual experiences that they believe are real. Hallucinations connected to religion or paranormal experiences seem to be quite common. Very often, these experiences cannot be called psychosis in a medical sense of the word. For this reason, some people have said that psychosis may simply be an extreme case of something that is experienced by most. People who have suffered from what could be called psychosis may simply have had experiences that were very strong or distressing.

In movies and the media in general, certain people who are shown as violent and antisocial are sometimes labelled psychotic. This image of psychosis is wrong, the people shown are usually psychopaths or sociopaths, they usually do not have hallucinations or delusions.

Psychosis is most associated with schizophrenia, bipolar disorder, depression, drug addiction and brain damage but it can be caused by a wide range of conditions.

Causes
Psychosis is not a disease but rather a name for a number of symptoms, that can be caused by different diseases and  conditions. Very broadly speaking there are two types of causes for psychosis:
In some cases, psychosis can be directly linked to a cause.  Some of the causes are:
Damage to the brain, tumors.
Wrongly using (or abusing) certain drugs; for example amphetamines, cocaine or alcohol
severe psychosocial stress
Lack of sleep This is not a problem for most people, as they will only experience hallucinations shortly before going to sleep or shortly after waking up, which is considered normal.
certain forms of epilepsy
exposure to some traumatic event (violent death, terrorist activity, etc.)
Certain drugs that are taken cannot simply be stopped from one day to the next, stopping them needs to be done in a certain way, usually assisted by a doctor. If this is not done the right way, psychosis can result.
Various mental illnesses (Schizophrenia, bipolar disorder, clinical depression are among them)
Different other diseases (syphilis, Alzheimer's disease, Parkinson's disease, AIDS, malaria, and leprosy are among them)
Syphilis Symptoms
There are certain cases of people who suffer from psychosis, where no cause for the psychosis is clear. In these cases, the causes are usually not known. Current research suggests that some of these psychoses may be linked to genetic factors, or due to certain events during the pregnancy of the mother, or the early childhood of the person suffering from psychosis. The first episode of psychosis may be triggered by stress.

Treatment
Most psychoses can be treated, so that those suffering from them can lead a normal life. The treatment depends on the cause of the psychosis. In general, there are two different forms of treatment available:
There is a class of drugs called  antipsychotics. These usually work by changing the way the brain and nervous system react to neurotransmitters.
There is therapy for psychotic people. This works by teaching them to recognise when they have an episode of psychosis, and to react to it in certain ways.

References