SPD and STPD both involve social impairment and isolation. STPD is generally more severe and may involve distorted perceptions, and disjointed thought or speech patterns.

Schizoid personality disorder (SPD) and schizotypal personality disorder (STPD) are personality disorders that occur on the schizophrenia disorder spectrum.

Though they share similarities, they have key differences that affect those living with either condition.

This article explains the similarities and differences between SPD and STPD, including the symptoms, diagnosis, and treatment of both conditions.

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SPD is a condition that involves a lack of interest in forming close relationships with others. Those with SPD may seem cold, aloof, or detached from other people and appear indifferent to others’ opinions of them.

Often, those with SPD do not feel strong emotions and may lean toward solitary pastimes or occupations.

With SPD, this lack of desire for close personal connection is not due to other conditions, such as depression, nor is it merely an individual preference. It is a lifelong trend starting in childhood that affects all aspects of a person’s life.

Symptoms

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) states that a person may have SPD if they experience a sense of detachment from others and express little emotion in social situations. The symptoms must persist from at least early adulthood, occurring in various circumstances.

To receive a diagnosis of SPD, a person must also meet at least four of the following criteria:

  • no interest in close relationships
  • a preference for solitary activities
  • little or no interest in sex
  • finds few activities enjoyable
  • seems detached or distant or lacking emotion

For a healthcare or mental health professional to diagnose SPD, these symptoms must not occur due to another condition, such as autism spectrum disorder, anxiety, or depression. These behaviors must also be atypical of the culture to which an individual belongs.

If someone comes from a culture where people typically have few friends, for example, having few close relationships may not indicate SPD. However, having no close relationships and no interest in forming them could be a symptom of SPD if this is not typical of the person’s culture.

Read more about schizoid personality disorder.

STPD is a personality disorder that affects a person’s behavior. Healthcare professionals categorize both STPD and SPD as cluster A personality disorders. This group of personality disorders presents with symptoms that others might consider eccentric or odd.

According to research from 2018, the prevalence of STPD in the United States is around 4.6% of the population, with males more likely than females to develop the condition.

Symptoms

People with STPD may display symptoms that include:

  • difficulty forming, or lack of interest in, close relationships
  • unusual beliefs, such as believing in magic, the supernatural, or telepathy
  • high social anxiety
  • eccentric behavior
  • atypical thought patterns
  • suspicion of others and their motives
  • distorted perceptions that are not hallucinatory in nature
  • bizarre, quirky, or affected speech and mannerisms
  • dressing or expressing themselves in unusual ways, such as wearing ostentatious or ill-fitting clothes

Read more about schizotypal personality disorder.

Although they share many overlapping symptoms, both conditions have some key differences, including:

Schizoid personality disorder (SPD)Schizotypal personality disorder (STPD)
Social relationships Those with SPD are unlikely to desire social relationships.Those with STPD may wish to form connections but have difficulties due to their eccentric or unusual behaviors.
Expressing emotionsA person displays few if any emotions.May appear to exhibit strong or unusual emotions.
Perceptions and beliefsA person typically does not experience unusual beliefs or perceptions.May experience distorted perceptions, believe in magic or superstition, or think they have supernatural powers.
Interpersonal attitudesIndifferent to praise or criticism from others.May experience high social anxiety and worry others do not share their beliefs or thoughts.
FunctioningMay experience significant social or occupational impairment.May function reasonably well despite social isolation.

Presentations of both SPD and STPD share several overlapping behaviors, both with each other and with other personality disorders, which can make diagnosis difficult.

Though the underlying reasons may differ, the social impairment that characterizes both SPD and STPD can present outwardly in similar ways with both conditions, including:

  • spending lots of time alone or pursuing solitary activities
  • having few, if any, close friends or confidants
  • little or no interest in sexual or romantic relationships or experiences
  • seeming detached and isolated
  • appearing “out of sync” with the world in a way that others could interpret as self-centered

Researchers do not yet fully understand the exact causes of personality disorders. However, many believe the causes to be genetic.

Some scientists believe that specific physical abnormalities, such as brain lobe lesions or diseases relating to biochemistry or neurotransmitters, may play a role in the development of SPD. However, more research is necessary to confirm this theory.

Older research from 2011 also suggests that lower family socioeconomic status may also be a risk factor for developing SPD in adolescents.

Read more about the causes of personality disorders.

Treatments for STPD include:

There is no specific treatment for SPD. Treatment is typically similar to that of other personality disorders.

A common treatment for personality disorders is psychotherapy. The general aims and principles of this type of talking therapy are:

  • to reduce the individual’s distress
  • to help someone understand that their problems are internal to themselves
  • to reduce socially maladaptive or problematic behaviors

The following are answers to some questions people frequently ask about SPD and STPD.

Which is more severe, schizoid or schizotypal?

Both conditions appear on the schizophrenia disorders spectrum. Healthcare professionals classify SPD as less severe than STPD, and STPD falls between SPD and schizophrenia — which is the most severe — on the spectrum.

Can you be both schizoid and schizotypal?

Yes. While they may not necessarily receive a diagnosis of both, many people with severe personality disorders can meet the diagnostic criteria for several conditions simultaneously. Doctors call these co-morbidities, which is why differential diagnoses can be challenging.

SPD and STPD are both cluster A personality disorders, which is the group that contains disorders involving eccentric or bizarre-seeming behaviors.

Both conditions cause significant social impairment. However, people with SPD often experience no desire for connection with others. That said, those with STPD may desire social relationships but feel unable to maintain them due to high social anxiety and an inability to regulate socially maladaptive behaviors.