What are the different types of schizophrenia spectrum and other psychotic disorders?

The particular combination of symptoms a person displays, and their duration, determines what diagnostic category they may fall into. There are five types of psychotic disorders described in the DSM-5-TR (see Table 4):

Schizophrenia.
Schizophreniform disorder.
Schizoaffective disorder.
Brief psychotic disorder.
Delusional disorder.

Table 4: Types of psychotic disorders

Disorder	Symptoms
Schizophrenia	Schizophrenia is one of the most common and disabling of the psychotic disorders. It affects a person’s ability to think, feel, and act. To be diagnosed with schizophrenia, two or more of the following symptoms must have been continuing for a period of at least six months: Delusions. Hallucinations. Disorganised speech. Grossly disorganised or catatonic behaviour. Negative symptoms (diminished emotional expression or avolition). These symptoms cause significant impairment in a person’s functioning at work, social relationships, or self-care. People are considered to have particular ‘types’ of schizophrenia depending upon the predominance of symptoms displayed (paranoid, disorganised, catatonic, undifferentiated, or residual type).
Schizophreniform disorder	Schizophreniform disorder is characterised by a symptomatic presentation that is equivalent to schizophrenia except its duration is limited to more than one month and less than six months, and it is not necessary to have a decline in social or occupational functioning.
Schizoaffective disorder	Schizoaffective disorder is characterised by the symptoms of schizophrenia alongside a major depressive or manic episode (described later in this chapter). This disorder may be divided into two types: Bipolar type (if the mood episode is manic). Depressive type (if the mood episode is major depressive).
Brief psychotic disorder	Brief psychotic disorder is a disturbance when delusions, hallucinations, or disorganised speech are present, with or without grossly disorganised or catatonic behaviour, for at least one day but less than one month.
Delusional disorder	Delusional disorder is characterised by at least one month of delusions. Hallucinations and other positive symptoms of schizophrenia are relatively absent, and functioning is not significantly impaired.

It should be noted that there are differences between the DSM-5-TR and ICD-11 classification systems regarding the types of psychotic disorders and their definitions. For example, ICD-11 does not distinguish between schizophrenia and schizophreniform disorder. Further, experiences of influence, passivity or control are recognised as separate from delusional symptoms of schizophrenia in ICD-11.

Box 2: Case study B: What does co-occurring psychosis and AOD use look like? Amal’s story

Case study B: Amal's story

Amal, a 21-year-old who identified as male, presented to his local AOD service at the insistence of his parents. Both his mother and father accompanied him to his appointment and joined in the consultation. When the AOD worker asked Amal what had brought him in, his father answered that they had brought Amal in because of his ongoing methamphetamine use. He said that Amal lived with them, and they had been aware of some methamphetamine use in the past. The last time they had become aware of Amal's methamphetamine use was approximately a year ago, and at that time Amal had promised not to use again. Amal's father appeared to be quite angry and explained to the AOD worker that Amal had agreed at that time that if he were ‘caught' using again, he would be brought straight to the AOD service.

During the assessment, Amal's father continued speaking and answering the AOD worker's questions on Amal's behalf. The AOD worker thanked Amal's parents for the support they showed in coming with Amal to his appointment and for being willing to be involved in his treatment planning – she spoke of the importance of active family involvement in helping people to achieve their goals. She asked Amal's parents to please go back to the waiting room for the remainder of Amal's assessment, until she was ready to discuss the next steps with the whole family. Once his parents left the room, Amal appeared to visibly relax. He said they were annoying, but he was happy for them to be involved in his treatment planning.

In talking about his methamphetamine use, Amal described periods of hallucinations and delusions that he has experienced in the past during the context of use but had not experienced these recently. He said that his neighbours were trying to obtain his family's house and had poisoned all of the plants in their front yard. After a discussion regarding various treatment options, Amal chose to try inpatient detoxification and Amal's family were happy with this plan.

A few days into Amal's detoxification, he began exhibiting suspicious and paranoid behaviours. His roommate complained to the nurse unit manager that Amal had been sitting up in his bed all night watching him sleep and believed he had gone through his belongings. Amal was also observed mumbling to himself. Upon questioning, Amal appeared to be highly paranoid, suspicious, watchful and guarded, was mumbling to himself and appeared to be responding to internal stimuli.

Key Points

What are the primary concerns for Amal?
Where to from here?

Case study B continues in Chapter B7.