Schizotypal personality disorder (StPD or SPD), also known as schizotypal disorder, is a mental disorder characterized by thought disorder, paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs. People with this disorder often feel pronounced discomfort in forming and maintaining social connections with other people, primarily due to the belief that other people harbor negative thoughts and views about them. People with StPD may react oddly in conversations, such as not responding as expected, or talking to themselves. They frequently interpret situations as being strange or having unusual meanings for them; paranormal and superstitious beliefs are common. Those with the disorder often score high on measures for self-disorder.
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) classifies StPD as a personality disorder belonging to cluster A, which is a grouping of personality disorders exhibiting traits such as odd and eccentric behavior. In the International Classification of Diseases, the latest edition of which is the ICD-11, schizotypal disorder is not classified as a personality disorder, but among psychotic disorders.
People with StPD usually disagree with the suggestion that their thoughts and behaviors are a disorder and seek medical attention for depression or anxiety instead. Schizotypal personality disorder occurs in approximately 3% of the general population and is more commonly diagnosed in males.
Signs and symptoms
Magical thinking Odd and magical thinking is common among people with StPD. They are more likely to believe in supernatural phenomena and entities. It is common for people with StPD to experience severe social anxiety and have paranoid ideation. Ideas of reference are common in people with StPD. They can feel as if expressing themselves is dangerous. They may also feel that others are more competent, and have deeply entrenched and pervasive insecurities. Strange thinking patterns may be a defense mechanism against these feelings. People with StPD usually have limited levels of self-awareness. They may believe others think of them more negatively than they actually do.
Affect Patients with StPD can have difficulties in recognizing their or others' emotions, which can extend to difficulty expressing emotion. They may have limited responses to others' emotions and can be ambivalent. It is common for people with StPD to derive limited joy from activities. People with StPD are typically more socially isolated and uninterested in social situations than people without StPD, although they are still likely to be socially active on the Internet. Depersonalization, derealization, boredom, and internal fantasies are common in patients with StPD. Abnormal facial expressions are also common in people with StPD, and they can have aberrant eye movements and difficulty responding to stimuli. They are often more prone to substance abuse or suicidal ideation. In an epidemiological study on suicidal behavior in StPD, even when sociodemographic factors were accounted for, people with StPD were 1.51 times more likely to attempt suicide. StPD is also often characterized as having similar symptoms as schizophrenia, but with less severe cognitive deficits.
Cognition People with StPD tend to have cognitive impairments. They can have abnormal perceptional and sensory experiences such as illusions. For example, someone with StPD may perceive colors as lighter or darker than others perceive them. Facial perception may also be difficult for people with the disorder. They may see others as deformed, misrecognize them, or feel as if they are alien to them. People with StPD can have difficulty processing information such as speech or language. They are more likely to speak slowly, with less fluctuation in pitch, and long pauses between speech. Patients with StPD may have a lower odor detection threshold, and can have impaired auditory or olfactory processing. It is also common for people with StPD to struggle with context processing, which cause them to form loose connections between events. In addition, people with StPD can have decreased capacities for multisensory integration or contrast sensitivity, either hyperreactive or impaired reactions to sensory input, slower response times, impaired attention, poorer postural control, and difficulties with decision-making. They can have difficulties in memory, and may have frequent intrusive memories of events. It is common for people with StPD to feel déjà vu or as if they can accurately predict future events due to abnormalities in the brain's memory storage.
Causes Genetic Although environmental factors likely play an important role in the onset of the disorder, people who have relatives with schizotypy, mood disorders, or other disorders on the schizophrenia spectrum are at a higher likelihood of developing StPD.
The COMT Val158Met polymorphism and its Val or Met alleles are suspected to be associated with schizotypal personality disorder. These genes affect dopamine production in the brain, a neurochemical thought to be associated with schizotypal traits. The gene may also contribute to decreased volumes of gray matter in the prefrontal cortex. This may lead to impaired capacities for decision-making, speech, cognitive flexibility, and altered perceptual experiences.
The rs1006737 polymorphism of the CACNA1C gene is also believed to have a part in schizotypal symptoms. It may lead to a significantly increased physiological response to stress through the cortisol awakening response in the brain. It may also negatively affect reward processing in the brain and lead to anhedonia or depression in patients. These factors possibly lead to the development of schizotypal traits.
The zinc finger protein 804A likely affects the levels of paranoia, anxiety, and ideas of reference in StPD. This gene is also thought to negatively impact attention in people with StPD. It may lead to an increased level of white matter volume in the frontal lobe.
Another gene, Notch 4, is thought to relate to schizophrenia spectrum disorders. It can lead to disruptions in the occipital cortex, and, therefore, to symptoms of schizotypy. The GLRA1 and the p250GAP genes are also potentially associated with StPD. It may lead to abnormally low levels of glutamic acids in NMDA receptors, which impairs memory and learning. StPD may stem from abnormalities in chromosome 22.
Neurological Exposure to influenza during week 23 of gestation is associated with a higher likelihood of developing StPD. Poor nutrition in childhood may also contribute to the onset of StPD by altering the course of brain development.
Numerous areas of the brain are thought to be associated with StPD. Higher levels of dopamine in the brain, possibly specifically the dopamine D1 receptor, might contribute to the development of StPD. StPD is associated with heightened dopaminergic activity in the striatum. Their symptoms may also stem from higher presynaptic dopamine release.
People with StPD may also have decreased volumes of grey or white matter in their caudate nucleus, which leads to difficulties in speech.
People with StPD likely have a reduced volume in their temporal lobes, possibly specifically the left hemisphere. The reduced levels of grey matter in these areas may be linked to their negative symptoms. Reduced volume of gray or white matter in the superior temporal gyrus or the transverse temporal gyrus are thought to lead to issues with speech, memory, and hallucinations. Deficits in the gray matter volume of the temporal lobe and prefrontal cortex are likely associated with impairments in cognitive function, sensory processing, speech, executive function, decision-making, and emotional processing present in people with StPD.
StPD symptoms may also be influenced by reduced internal capsule, which carries information to the cerebral cortex. People with StPD can also have impairments in the uncinate fasciculus, which connects parts of the limbic system. People with StPD have reduced levels of gray matter in their middle frontal gyrus and Brodmann area 10, although not as reduced as patients with schizophrenia, possibly preventing them from developing schizophrenia. Increased gyrification in gyri by the cerebellum may lead to dysconnectivity in the brain, and therefore, schizotypal symptoms.
Individuals with the disorder may also have a hyporeactive or hyperreactive amygdala, as well as hyperactive pituitary glands and putamens.
It is also possible that lower capacities for prepulse inhibition play a role in StPD. Research has suggested that people with StPD can have higher concentrations of homovanillic acids. Abnormalities in the cave of septum pellucidum may also be present.
In people predisposed to schizophrenia spectrum disorders, the consumption of cannabis can induce the onset of StPD or other disorders with psychotic symptoms.
Environmental Unique environmental factors, which differ from shared sibling experiences, have been found to play a role in the development of StPD and its dimensions. There is evidence to suggest that parenting styles, early separation, childhood trauma, and childhood neglect can lead to the development of schizotypal traits.Deidre M. Anglina, Patricia R. Cohenab, Henian Chena (2008) Duration of early maternal separation and prediction of schizotypal symptoms from early adolescence to midlife, Schizophrenia Research Volume 103, Issue 1, Pages 143–150 (August 2008)Howard Berenbaum, Ph.D., Eve M. Valera, Ph.D. and John G. Kerns, Ph.D. (2003) Psychological Trauma and Schizotypal Symptoms, Oxford Journals, Medicine, Schizophrenia Bulletin Volume 29, Number 1 Pp. 143–152 Neglect, abuse, stress, trauma, or family dysfunction during childhood may increase the risk of developing schizotypal personality disorder. People with the most severe cases of StPD usually have a combination of childhood trauma and a genetic basis for their condition.
During childhood, people with StPD may have seen little emotional expression from their parents. Another possibility is that they were excessively criticized or felt like they were constantly under threat, potentially resulting in the onset of social anxiety, strange thinking patterns, and blunted affect present in StPD.
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. Their difficulties in social situations might eventually cause the individual to withdraw from most social interactions, thus leading to asociality. Children with schizotypal symptoms usually are more likely to indulge in internal fantasies and are more anxious, socially isolated, and sensitive to criticism.
There is also evidence indicating that disruptions in brain development during the prenatal period could affect the development of StPD.
Diagnosis
Classification
The two most prominent frameworks for classification of mental disorders are the Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Classification of Diseases (ICD). While classified as a personality disorder in the DSM-5; under the name schizotypal disorder, it is classified among schizophrenia spectrum disorders in the ICD-11 and previous revisions of the ICD. Approaches to classification of personality disorders vary.
DSM-5