It can feature auditory hallucinations, or hearing things that are not there. Less commonly, the person may experience visual hallucinations, in which they see things that do not exist.
There may be bizarre or paranoid delusions, and disorganized speech and thinking.
Schizophrenia is normally diagnosed in early adulthood. The United States (U.S.) Centers for Disease Control and Prevention (CDC), estimate that schizophrenia affects between between 0.6 and 1 percent of the global population.
Classification and diagnosis
Schizophrenia is a serious mental health issue.
In the past, there were different subtypes of schizophrenia, including:
- paranoid schizophrenia
- disorganized, or hebephrenic schizophrenia
- catatonic schizophrenia
- childhood schizophrenia
- schizoaffective disorder
In 2013 the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-V) changed the method of classification to bring all these categories under a single heading: schizophrenia.
According to the American Psychiatric Association (APA), the decision to eliminate these various subtypes was based on the conclusion they had "limited diagnostic stability, low reliability, and poor validity." It was concluded that they did not help to provide better treatment or to predict how patients would respond to treatment.
Two other important changes were made to the diagnostic criteria in 2013.
One was the removal of the requirement for a person to experience bizarre delusions and to hear two or more voices talking during an auditory hallucination to receive a positive diagnosis.
The second was that, to receive a diagnosis, a person must have at least one of the following symptoms:
- disorganized speech
Click here for a more comprehensive article on schizophrenia.
The following used to be subtypes of schizophrenia. Find out what has changed in the use of these categories.
A person with schizoaffective disorder experiences a combination of schizophrenia symptoms, such as hallucinations and delusions, and mood disorder symptoms, such as mania or depression.
In the past, the person had to have both sets of symptoms at the same time to receive a diagnosis of schizoaffective disorder.
The DSM-V update in 2013 now says that to be diagnosed with schizoaffective disorder, a person must have experienced mood disorders for most of the time they have also had the psychotic symptoms of schizophrenia, from when they first started having symptoms up to the present.
Catatonia includes extremes of behavior:
- Catatonia can include excessive and peculiar motor behaviors, sometimes referred to as catatonic excitement
- Catatonia can also include decreased motor activity and engagement. For example, people in a catatonic stupor demonstrate a dramatic reduction in activity, where the patient cannot speak, move or respond. Virtually all movements stop.
Catatonia can occur with schizophrenia and a range of other conditions including bipolar disorder. For this reason, it is now considered a specifier for schizophrenia and other mood disorders, rather than a type of schizophrenia.
Childhood onset schizophrenia
The symptoms of schizophrenia normally appear during early adulthood, but they can sometimes emerge during childhood, at the age of 10 years or earlier. It is extremely rare, with an incidence of less than 0.04 percent.
If schizophrenia occurs in a child, it is very serious, and treatment is needed.
However, healthy children can experience hallucinations, so if this happens, it does not mean that a child has schizophrenia.
Disorganized schizophrenia, or hebephrenia
Disorganized thinking and behavior are features of schizophrenia. The person may have incoherent and illogical thoughts and speech.
This can make it difficult to perform daily activities, such as preparing meals and taking care of personal hygiene, or washing. People may not be able to understand what the patient is saying. This can lead to frustration and agitation.
While disorganization is a feature of schizophrenia, it is no longer considered a separate subtype.
Paranoid SchizophreniaA person with schizophrenia may have false beliefs, or delusions, that an individual or group of people are conspiring to harm them or members of their family. They may spend time thinking about ways to protect themselves from the people they believe are persecuting them.
While delusions can still be key to a diagnosis of schizophrenia, this is no longer considered a separate subtype of the disorder.