Schizotypal personality disorder

Schizotypal personality disorder is widely understood to be a "schizophrenia spectrum" disorder. Rates of schizotypal personality disorder are much higher in relatives of individuals with schizophrenia than in the relatives of people with other mental illnesses or in people without mental illness. Technically speaking, schizotypal personality disorder may also be considered an "extended phenotype" that helps geneticists track the familial or genetic transmission of the genes that are implicated in schizophrenia pathogenesis.[7] But there is also a genetic connection of STPD to mood disorders and depression in particular.[8] Prediction of schizophrenia based on schizotypal traits has a higher accuracy for individuals with high genetic risk for STPD.[9]

Unique environmental factors, which differ from shared sibling experiences, have been found to play a role in the development of STPD and its dimensions.[6] There is now evidence to suggest that parenting styles, early separation, trauma/maltreatment history (especially early childhood neglect) can lead to the development of schizotypal traits.[10][11] Neglect or abuse, trauma, or family dysfunction during childhood may increase the risk of developing schizotypal personality disorder. There is also evidence indicating influenza in the prenatal environment could have an effect on development of STPD.[12] Over time, children learn to interpret social cues and respond appropriately but for unknown reasons this process does not work well for people with this disorder.[13]

Schizotypal personality disorders are characterized by a common attentional impairment in various degrees that could serve as a marker of biological susceptibility to STPD.[14] The reason is that an individual who has difficulties taking in information may find it difficult in complicated social situations where interpersonal cues and attentive communications are essential for quality interaction. This might eventually cause the individual to withdraw from most social interactions, thus leading to asociality.[14]

There are various methods of screening for schizotypal personality. The Schizotypal Personality Questionnaire (SPQ) measures nine traits of STPD using a self-report assessment. The nine traits referenced are Ideas of Reference, Excessive Social Anxiety, Odd Beliefs or Magical Thinking, Unusual Perceptual Experiences, Odd or Eccentric Behavior, No Close Friends, Odd Speech, Constricted Affect, and Suspiciousness. A study found that of the participants who scored in the top 10th percentile of all the SPQ scores, 55% were clinically diagnosed with STPD.[15] A method that measures the risk for developing psychosis through self-reports is the Wisconsin Schizotypy Scale (WSS).[16] The WSS divides schizotypal personality traits into 4 scales for Perceptual Aberration, Magical Ideation, Revised Social Anhedonia, and Physical Anhedonia.[17][18][3] A comparison of the SPQ and the WSS suggests that these measures should be cautiously used for screening purposes of STPD.[18]

In the American Psychiatric Association's DSM-5, schizotypal personality disorder is defined as a "pervasive pattern of social and interpersonal deficits marked by acute discomfort with, and reduced capacity for, close relationships as well as by cognitive or perceptual distortions and eccentricities of behavior, beginning by early adulthood and present in a variety of contexts."[3]

At least five of the following symptoms must be present:

• ideas of reference
• strange beliefs or magical thinking that influences behavior and is inconsistent with subcultural norms (e.g., superstitiousness, belief in clairvoyance, telepathy, or “sixth sense”, bizarre fantasies or preoccupations)
• abnormal perceptual experiences, including bodily illusions
• strange thinking and speech (e.g., vague, circumstantial, metaphorical, overelaborate, or stereotyped)
• inappropriate or constricted affect
• strange behavior or appearance
• excessive social anxiety that does not diminish with familiarity and tends to be associated with paranoid fears rather than negative judgments about self

These symptoms must not occur only during the course of a disorder with similar symptoms (such as schizophrenia or autism spectrum disorder).[3]

The symptoms of "lacking close friends" and "suspiciousness or paranoia" have been used for diagnosing STPD by the DSM-V. These criteria overlap with symptoms for Paranoid personality disorder (PPD) and Schizoid personality disorder (SzPD), making these symptoms not as useful when distinguishing STPD from other personality disorders. [6]

The World Health Organization's ICD-10 uses the name schizotypal disorder (F21). It is classified as a clinical disorder associated with schizophrenia, rather than a personality disorder as in DSM-5.[19]

The ICD definition is:

A disorder characterized by eccentric behavior and anomalies of thinking and affect which resemble those seen in schizophrenia, though no definite and characteristic schizophrenic anomalies have occurred at any stage. There is no dominant or typical disturbance, but any of the following may be present:

• Inappropriate or constricted affect (the individual appears cold and aloof);
• Behavior or appearance that is odd, eccentric or peculiar;
• Poor rapport with others and a tendency to withdraw socially;
• Odd beliefs or magical thinking, influencing behavior and inconsistent with subcultural norms;
• Suspiciousness or paranoid ideas;
• Obsessive ruminations without inner resistance;
• Unusual perceptual experiences including somatosensory (bodily) or other illusions, depersonalization or derealization;
• Vague, circumstantial, metaphorical, over-elaborate or stereotyped thinking, manifested by odd speech or in other ways, without gross incoherence;
• Occasional transient quasi-psychotic episodes with intense illusions, auditory or other hallucinations and delusion-like ideas, usually occurring without external provocation.

The disorder runs a chronic course with fluctuations of intensity. Occasionally it evolves into overt schizophrenia. There is no definite onset and its evolution and course are usually those of a personality disorder. It is more common in individuals related to people with schizophrenia and is believed to be part of the genetic "spectrum" of schizophrenia.

This diagnostic rubric is not recommended for general use because it is not clearly demarcated either from simple schizophrenia or from schizoid or paranoid personality disorders, or possibly autism spectrum disorders as currently diagnosed. If the term is used, three or four of the typical features listed above should have been present, continuously or episodically, for at least two years. The individual must never have met criteria for schizophrenia itself. A history of schizophrenia in a first-degree relative gives additional weight to the diagnosis but is not a prerequisite.

STPD is rarely seen as the primary reason for treatment in a clinical setting, but it often occurs as a comorbid finding with other mental disorders. When patients with STPD are prescribed pharmaceuticals, they are usually prescribed neuroleptics, also known as antipsychotics, of the sort used to treat schizophrenia; however, the use of neuroleptic drugs in the schizotypal population is in great doubt.[20] While people with schizotypal personality disorder and other attenuated psychotic-spectrum disorders may have a good outcome with neuroleptics in the short term, long-term follow-up suggests significant impairment in daily functioning compared to schizotypal and even schizophrenic people without neuroleptic drug exposure.[21] Positive, negative, and depressive symptoms were shown to be improved by the used of olanzapine, a neuroleptic. [22] Those with comorbid OCD and STPD were most positively affected by the use of olanzapine, and showed worse outcomes with the use of clomipramine, an antidepressant. [23]

Antidepressants are also sometimes prescribed, whether for STPD proper or for comorbid anxiety and depression.[20] However, there is some ambiguity in the efficacy of antidepressants, as many studies have only tested people with STPD and comorbid obsessive-compulsive disorder or borderline personality disorder. They have shown little efficacy for treating dysthymia and anhedonia related to STPD. [6]

Both of these medications are the most frequently prescribed medication for STPD, though the use and efficacy of them should be evaluated differently for every case.[22]

The use of stimulants have also shown some efficacy, especially for those with worsened cognitive and attentional issues. Patients that suffer from concurrent psychosis should be monitored more closely if stimulants are used as part of their treatment. [6]

According to Theodore Millon, schizotypal personality disorder is one of the easiest personality disorders to identify but one of the most difficult to treat with psychotherapy.[5] Persons with STPD usually consider themselves to be simply eccentric or nonconformist; the degree to which they consider their social nonconformity a problem differs from the degree to which it is considered a problem in psychiatry. It is difficult to gain rapport with people with STPD due to the fact that increasing familiarity and intimacy usually increase their level of anxiety and discomfort.[24]

Group therapy is recommended for persons with STPD only if the group is well structured and supportive. Otherwise, it could lead to loose and tangential ideation.[20] Support is especially important for schizotypal patients with predominant paranoid symptoms, because they will have a lot of difficulties even in highly structured groups.[25]