When searching “schizotypal” around the net, you may have seen it referred to either as a personality disorder or simply a disorder.

Why is that, and what’s the difference?

I’ve dug through a few internet pages including APA’s (American Psychiatric Association) homepage and various danish sites on psychiatry and mental health information pages.

Far as I can tell, the main difference lies simply in the diagnostics system. There are two distinct, primary diagnostics systems used in psychiatry largely depending on where you live in the world: ICD (International Classification of Disease) and DSM (Diagnostic and Statistical Manual of Mental Disorders).

ICD is developed by WHO (World Health Organization). It is primarily used in Europe and various countries connected to WHO. It is the official diagnostics system used in Denmark, where I live. The newest iteration and currently used version is ICD-10. In this system, schizotypal is listed as a disorder. Here, it is loosely grouped with psychotic disorders such as Schizophrenia, paranoid delusions and acute or passing psychoses. This, I believe is due to the relationship and similarity to schizophrenia.

DSM is published by APA and is primarily used in USA, Canada and Australia. If memory serves correctly, it is also the system most commonly used in research papers. The newest iteration and current version in use is DSM-5. In this system, schizotypal is listed as a personality disorder. It is classed as a cluster A personality disorder, which is known as the “eccentric personality disorders” along with schizoid and paranoid personality disorders.

There are a total of 3 clusters of personality disorders in DSM-5.
B is the dramatic, emotional, irratic cluster, which consists of antisocial, histrionic, narcissistic and borderline personality disorders. cluster C is the fearful, anxious cluster and consists of avoidant, dependant and obsessive compulsive personality disorders.
So, what is a personality disorder? It is a type of disorder so deeply ingrained in a person’s behavior and way of thinking that it could be considered a distinct part of their personality. Roughly speaking. Symptoms typically become apparent during adolescence and cause long-term difficulties in personal relationships and function in society.

Essentially, Schizotypal Disorder and Schizotypal Personality Disorder are the same disorder, only classified differently, with slight variations. Symptoms are essentially the same. In DSM-5, the symptoms have to appear even without outside stressors, whereas ICD-10 is slightly more lenient in this. In practice, there’s hardly any difference that I could detect.

I might remember this wrong, but I believe the difference in classification comes from the structure of the diagnostics system. In ICD-10, disorders are largely classified on a spectrum or several, like autism spectrum disorders, whereas in DSM-5, they are largely categorical.

By calling it a personality disorder, DSM-5 focuses on the distinct pattern of thought and behavior in people with schizotypal personality disorder, which deviates from what is considered normal in society. Personality disorders affect the way one thinks of oneself, relates to other people, responds emotionally and controls one’s behavior. These problematic behaviors and thinking patterns persist over very long periods of time and treating a personality disorder can be a lengthy endeavor both with psychotherapy and if needed, medication. The fact that psychotic symptoms such as delusions and hallucinations are very limited or entirely non-existent probably also plays a role in this classification.

ICD-10 on the other hand seems to primarily consider the similarity of shizotypal disorder to schizophrenia. Research has shown a fairly strong familial relationship between schizophrenia and schizotypal disorder where families with cases of schizophrenia are more likely to also have cases of schizotypal disorder. Another reason for this classification might be the hierarchical nature of ICD-10, where disorders are ranked by numbers where the lower numbers take priority over lower numbers. So if someone has symptoms fitting into several different disorders, it is the disorder listed first in the system that takes priority. That way if I have enough symptoms to be diagnosed with both schizotypal disorder and bipolar disorder, depression or anxiety, it is the schizotypal disorder that is diagnosed first while any symptoms of the other disorders are treated as part of my schizotypal disorder. I’d guess this is to prevent over-long, messy diagnoses.

I am slightly more familiar with ICD-10, but I am by no means an expert in either diagnostics system, so there’s a good chance I got some things wrong. If you spot any mistakes, please correct me in the comments.

In this blog I use the term schizotypal disorder, because that is the term I am most familiar with.

TL;DR version: DSM-5 is American and calls it a personality disorder, ICD-10 is European and calls it a disorder related to schizophrenia.