What are schizophrenia spectrum and other psychotic disorders?

Schizophrenia spectrum and other psychotic disorders are among the most stigmatised disorders, even within healthcare. Historically, these disorders have not been well understood and people experiencing them have been marginalised, ostracised, incarcerated, and institutionalised. Although the term ‘schizophrenia’ literally means ‘split mind’, these disorders are not associated with any ‘multiple personality’ or dissociative disorders. Rather, schizophrenia refers to what is sometimes called a ‘split’ from reality.

The current classification systems consider schizophrenia to be on a spectrum of disorders that vary in terms of symptom severity and duration, all with similar symptoms. A person experiencing schizophrenia spectrum or other psychotic disorders can lose touch with reality. Their ability to make sense of both the world around them and their internal world of feelings, thoughts, and perceptions is severely altered. The most prominent symptoms are delusions, hallucinations, disorganised thinking, grossly disorganised or abnormal behaviour, and negative symptoms (see Table 3), which are not attributable to the effects of AOD use or withdrawal, medication use, or another physical condition (e.g., brain tumour). In general, these symptoms are clustered into three main categories: positive, negative and disorganised symptoms.

Table 3: Predominant symptoms associated with schizophrenia spectrum and other psychotic disorders

Positive symptoms: Behaviours or symptoms that are abnormally present
Delusions are fixed beliefs that usually involve a misinterpretation of perceptions or experiences and are resistant to change in light of conflicting evidence. For example, people who experience delusions may feel that someone is out to get them, that they have special powers, or that passages from the newspaper have special meaning for them. Delusions can be either bizarre or non-bizarre. Bizarre delusions are those that are clearly implausible, not understandable to same-culture peers, and not derived from ordinary life experiences (e.g., the belief that one’s brain has been removed and replaced with someone else’s without leaving any wounds or scars). Non-bizarre delusions are those which involve situations that could conceivably occur in real life (e.g., being followed, poisoned, or deceived by one’s partner).
Hallucinations are false perceptions such as seeing, hearing, smelling, sensing, or tasting things that others cannot. These are vivid and clear, with the impact of regular perceptions, and are not under voluntary control. Hallucinations can occur in any sensory modality but auditory hallucinations, experienced as voices distinct from a person’s own thoughts, are the most common in schizophrenia and related disorders. It is important to note that the classification of an experience as either a delusion or a hallucination is dependent upon culture. That is, the experience must be one that most members of that culture would consider a misrepresentation of reality.
Negative symptoms: Behaviours or symptoms that are abnormally absent
Negative symptoms account for much of the morbidity associated with schizophrenia but are less prominent in other psychotic disorders. These include: Diminished emotional expressiveness (i.e., reductions in intensity of emotional expressiveness). Avolition (i.e., lack of interest in initiating or continuing with activities). Alogia (i.e., restricted speech fluency and productivity of thought and speech). Anhedonia (i.e., restricted ability to experience pleasure from positive stimuli). Asociality (i.e., a lack of interest in social interactions).
Disorganised symptoms: Jumbled thoughts, behaviours, or speech
Disorganised speech usually reflects disorganised thinking, and involves difficulty with communication, through difficulty keeping track of conversations, switching between unrelated topics, with incoherent words or sentences. A person’s speech might be rambling with tangential ideas, with speech that can be difficult to understand, or even incoherent. These unconnected ideas and sentences are sometimes called a ‘word salad’.
Grossly disorganised or abnormal behaviour may be evident in several ways, ranging from inappropriate behaviour or silliness to unpredictable agitation. There may be problems with goal-directed behaviour interfering with usual daily activities, or difficulty with activities of daily living. Catatonic behaviour, which is a decreased reactivity to the environment (sometimes to the extreme of complete unawareness, maintaining a rigid or inappropriate posture, or complete lack of verbal or motor response) may be present, which can include purposeless and excessive motor activity.

People with AOD use disorders may display symptoms of psychosis that are due to either intoxication or withdrawal from substances. However, if the person experiences psychotic episodes even when they are not intoxicated or withdrawing, it is possible that they may have one of the disorders described in Table 4. Schizophrenia spectrum and other psychotic disorders are severely disabling mental disorders. Psychotic symptoms may also present in people with major depressive disorder or bipolar I disorder, or from a medical condition.

A case study example of how a person experiencing co-occurring psychosis and AOD use disorder may present is illustrated in Box 2.

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