Biological Links to Eccentric Behavior

By Vidya Koesmahargyo

The most prevalent symptom of schizotypal personality disorder are the odd or eccentric beliefs and behavior of the individual. Depending on the severity, people with StPD can experience moderate to serious impairment in their day-to-day lives, as these unusual thoughts and consequent behaviors can affect their relationship with the people closest to them. (Bressert, 2014) They may have trouble forming relationships or understanding the impact of their behavior on others, and may also misinterpret others’ motivations and behaviors and develop significant distrust of others. These social misconceptions may lead to severe anxiety and a tendency to turn inward in social situations, causing even further isolation for people with StPD.

For neurotypical people, whose pattern of thinking are more or less organized, (though it may not always feel as so), mental disorders like StPD are a little hard to understand. The specific oddities may vary on an individual basis, but current diagnosis of StPD tends to focus on two criteria:

1. Cognitive-perceptual criteria: ideas of reference, odd beliefs, and perceptual disturbance, and

2. Oddness criteria: that is, odd behavior, odd speech and/or thought processes, and restricted affect. (Hummelen, 2012)

Simply put, the severity of StPD depends on perception, and oddness within that perception, while still not crossing over to any diagnostic criteria for schizophrenia. As a consequence, individuals with StPD often have poor real-world social adjustment, despite having relatively intact mental and social cognition. Studies have been done to map out cognitive structures that may have been unusually affected by the disorder, and how they affect social interaction.

In a study by Hur et. al, people with StPD display higher activity in the part of the brain involved in reward and decision making in response to the stimuli of biological motion, or body language. This suggests that these enhanced responses are possibly related to the peculiar ways that individuals with SPD behave in social contexts. The specific link between higher activation levels and odd thinking and behavior has not been investigated, but the researchers suggest that the hyperactive neurons result in a patient’s eccentric behavior, and inability to form coherent social interactions. It is important to note that despite possible biological links, mental illnesses such as personality disorders still have very real social and psychological implications that can not be dismissed by biological bases. Biological factors are only one facet in a multitude in understanding how neurological disorders work, how it affects the people with it and how we can provide better care for them.

Works Cited:

Bressert, S. (2014). Schizotypal Personality Disorder Symptoms. Psych Central. Retrieved on February 24, 2016, from

Hummelen  B, Pedersen  G, Karterud  S.  Some suggestions for the DSM-5 schizotypal personality disorder construct. Compr Psychiatry. 2012;53(4):341-349.

Hur, J., Blake, R., Cho, K. I., Kim, J., Kim, S., Choi, S., . . . Kwon, J. S. (2016). Biological Motion Perception, Brain Responses, and Schizotypal Personality Disorder. JAMA Psychiatry, 73(3), 260. Retrieved April 3, 2016.

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