Psychosis is not a diagnosis but rather a feature or episode prevalent in several mental health diagnoses. Psychotic episodes (an incidence of psychosis) can look quite different but have in common some kind of "break from reality." These can include false beliefs (believing something has happened or is the case in spite of rational evidence to the contrary--delusions), hallucinations (most commonly auditory, particularly voices, but visual and other senses can be engaged), or thought disorder (typically highly disorganized or confused speech).
A number of non-psychiatric factors can cause psychosis, including drug use (both legal and non-legal drugs), brain tumors, epilepsy, and extreme sleep deprivation.
On the mental-health side, schizophrenia is the most common disorder featuring psychosis. Psychosis is also often associated with bipolar disorder, particularly manic episodes. Many are less aware that psychosis can also accompany extreme episodes of depression.
Historically, psychosis is treated with anti-psychotic medications, and while this is the most common option, many who experience psychosis, as well as mental-health advocates, challenge the assumption that psychiatric medications are always a necessity in treating psychotic symptoms. It is also important to note that anti-psychotic medications, including some of the newer "atypical" anti psychotic medications have serious, unpleasant side effects including intense weight gain, changes in hormones, difficulties sleeping, and hair loss.
While most people who suffer from psychotic symptoms choose to take medication and endure these side effects rather than endure the symptoms of their psychosis, it is important that individuals in this predicament be given autonomy whenever possible and supported through guidance and advocacy in their work with their psychiatrist or psychiatric nurse practitioner.
The common position among psychotherapists is that individuals who experience psychosis are not good candidates for talk therapy because their condition interferes with their ability to make use of the therapeutic work. In short, therapists typically believe that individuals with psychosis are "too crazy" to benefit from an activity designed to support them in creating their lives. While we do not believe that every person can benefit from therapy, we do not advocate a position that an entire class of people cannot. In many cases, individuals with occasional or chronic psychosis are able to gain help in therapy in building their lives, with all of the challenges in those lives, including psychosis.