Schizotypal disorder

Essential (Required) Features:

• An enduring pattern of unusual speech, perceptions, beliefs and behaviours that are not of sufficient intensity or duration to meet the diagnostic requirements of Schizophrenia, Schizoaffective Disorder, or Delusional Disorder. The pattern includes several of the following symptoms:
• Constricted affect, such that the individual appears cold and aloof;
• Behaviour or appearance that is odd, eccentric, unusual, or peculiar and is inconsistent with cultural or subcultural norms;
• Poor rapport with others and a tendency towards social withdrawal;
• Unusual beliefs or magical thinking influencing the person’s behaviour in ways that are inconsistent with subcultural norms, but not reaching the diagnostic requirements for a delusion;
• Unusual perceptual distortions such as intense illusions, depersonalization, derealization, or auditory or other hallucinations;
• Suspiciousness or paranoid ideas;
• Vague, circumstantial, metaphorical, overelaborate, or stereotyped thinking, manifest in odd speech without gross incoherence;
• Obsessive ruminations without a sense that the obsession is foreign or unwanted, often with body dysmorphic, sexual, or aggressive content.
• The individual has never met the diagnostic requirements for Schizophrenia, Schizoaffective Disorder, or Delusional Disorder. That is, transient delusions, hallucinations, formal thought disorder, or experiences of influence, passivity or control may occur, but do not last for more than 1 month.
• Symptoms should have been present, continuously or episodically, for at least 2 years.
• The symptoms cause distress or impairment in personal, family, social, educational, occupational or other important areas of functioning.
• The symptoms are not a manifestation of another medical condition (e.g., a brain tumour), are not due to the effects of a substance or medication on the central nervous system (e.g., corticosteroids), including withdrawal effects (e.g., from alcohol), and are not better accounted for by another Mental, Behavioural, or Neurodevelopmental Disorder.

Additional Clinical Features:

• Schizotypal Disorder is more common in biological relatives of persons with a diagnosis of Schizophrenia and is considered to be a part of the spectrum of Schizophrenia-related psychopathology. Having a first-degree relative with Schizophrenia gives additional weight to a diagnosis of Schizotypal Disorder but is not a requirement if the individual is experiencing distress or impairment in psychosocial functioning related to their symptoms.

Boundary with Normality (Threshold):

• The threshold between symptoms of Schizotypal Disorder and extravagant, eccentric, or unusual behaviour and beliefs in individuals without a diagnosable disorder is sometimes difficult to determine, especially as some people in the general population show eccentric behaviour and report psychotic-like or unusual subjective experiences without any apparent impairment in functioning. Schizotypal Disorder should only be diagnosed if the individual is experiencing distress or impairment in personal, family, social, educational, occupational or other important areas of functioning related to their symptoms.

Course Features:

• The course of Schizotypal Disorder is relatively stable and chronic, with some fluctuation in symptom intensity. Individuals often have severe functional impairments in academic, occupational, and interpersonal domains.
• The symptoms of Schizotypal Disorder are typically present prior to full symptomatic onset:
• Poor rapport with others and a tendency towards social withdrawal, suspiciousness or paranoid ideas; and
• Vague, circumstantial, metaphorical, overelaborate, or stereotyped thinking, manifested in odd speech without gross incoherence.
• The disorder may persist over years with fluctuations of intensity and symptom expression but rarely evolves into Schizophrenia.
• Affected individuals typically seek treatment for co-occurring Depressive or Anxiety or Fear-Related Disorders. Although intervention has demonstrated some efficacy in improving mood and anxiety symptoms, suspicion and paranoia often persist.

Developmental Presentations:

• Schizotypal Disorder typically begins in late adolescence or early adulthood, without a definite age of onset.
• Some symptoms of Schizotypal Disorder may first appear in childhood and adolescence affecting peer relationships and academic performance.

Culture-Related Features:

• A person’s behaviour, appearance, speech, or illness explanations may appear odd or unusual to clinicians who are unfamiliar with the person’s culture, but in the context of the person’s cultural group may be either normative or not be sufficiently severe as to reach the threshold of a mental disorder. Concepts and experiences that are common in some cultures include witchcraft or sorcery, speaking in tongues, life beyond death, shamanism, mind reading, sixth sense, evil eye, spirit possession, and magical beliefs related to health and illness.
• Reduced engagement in interpersonal relationships may be part of some cultural or religious practices (e.g., monastic isolation) and should not be considered pathological.

Sex- and/or Gender-Related Features:

• Schizotypal Disorder is slightly more common in males.

Boundaries with Other Disorders and Conditions (Differential Diagnosis):

• Boundary with Schizophrenia: In the prodromal and residual phases of Schizophrenia, the individual may experience extended periods of perceptual distortions, unusual beliefs, odd or digressive speech, social withdrawal, and other symptoms that are characteristic of Schizotypal Disorder. A diagnosis of Schizophrenia, however, requires a period of at least 1 month of psychotic symptoms, in contrast to Schizotypal Disorder, which requires that any psychotic-like symptoms not meet the diagnostic requirements for Schizophrenia in terms of severity or duration. Moreover, the pattern of unusual speech, perceptions, beliefs and behaviours tends to be stable over time—even over years—in individuals with Schizotypal Disorder, in contrast to an evolving symptom picture either in prodromal or residual phases of Schizophrenia.
• Boundary with Autism Spectrum Disorder: Interpersonal difficulties seen in Schizotypal Disorder may share some features of Autism Spectrum Disorder, including poor rapport with others and social withdrawal. However, individuals with Schizotypal Disorder do not exhibit restricted, repetitive and stereotyped patterns of behaviour, interests, or activities.
• Boundary with Personality Disorder: Personality Disorder is defined as an enduring disturbance in the individual’s way of interpreting and experiencing himself or herself, others, and the world that result in maladaptive patterns of emotional expression and behaviour, and produce significant problems in functioning that are particularly evident in interpersonal relationships. Individuals with Schizotypal Disorder should not be given an additional diagnosis of Personality Disorder based on disturbances in functioning and interpersonal relationships that are entirely a consequence of the symptoms of Schizotypal Disorder. However, if additional personality features are present that are judged to produce significant problems in interpersonal functioning, an additional diagnosis of Personality Disorder may be appropriate.