Continuing Education Activity

Schizoid personality disorder is a psychiatric disorder distinguished by detachment from social relationships and a restricted range of emotional expression in interpersonal settings. People with schizoid personality disorder are described as aloof, blunted, isolated, disengaged, and distant. The origins of schizoid personality disorder are complex and involve genetic, environmental, and psychological factors. The diagnosis of schizoid personality disorder is made using criteria described in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR). Schizoid personality disorder can adversely affect multiple aspects of life, underscoring the need for early intervention and interdisciplinary care. This activity illustrates the evaluation and management of schizoid personality disorder and highlights the role of the interdisciplinary team in improving care for patients with this condition.

Objectives:

• Identify the DSM-5-TR diagnostic criteria for schizoid personality disorder.
• Assess the etiology of personality development, including the role of temperament in schizoid personality disorder.
• Evaluate the available evidence for therapeutic interventions for schizoid personality disorder to effectively develop and implement an interdisciplinary treatment plan.
• Collaborate with interdisciplinary team members, including psychologists, psychiatrists, social workers, psychiatric-mental health nurse practitioners, psychiatric nurses, and primary care practitioners, to provide efficient, comprehensive, and coordinated care for patients with schizoid personality disorder.

Introduction

A pervasive pattern of detachment from social relationships and a restricted range of expression of emotions in interpersonal settings characterize schizoid personality disorder. Individuals with schizoid personality disorder have significant social withdrawal and can be viewed by others as eccentric, solitary, or isolated. People with schizoid personality disorder have considerable discomfort with social interactions, and their introversion is used as a defense mechanism to avoid psychological discomfort. The adjective "schizoid" was initially coined to describe the prodromal seclusiveness and isolation observed in schizophrenia. "Schizoid" originated with Bleuler,[1][2] and has been listed in each edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM). However, schizotypal personality disorder was not introduced in the DSM until 1980 (DSM-III). Before then, the diagnosis of schizoid personality disorder included the broad spectrum of both personality disorders, described as "non-psychotic schizophrenia-type illness."[1] Since the publication of DSM-III, schizoid personality disorder has been among the least studied personality disorders, with limited empirical investigations. Unfortunately, the personality disorders that have been associated with considerable decreases in quality of life include schizoid personality disorder, as well as avoidant, schizotypal, and borderline personality disorders;[3] there is a need for further research on these personality disorders.

Personality disorders are commonly grouped into 3 clusters based on shared characteristics consistent with the DSM-5-TR. These have classically been referred to as Cluster A, Cluster B, and Cluster C. Cluster A refers to personality disorders with odd or eccentric characteristics, including paranoid personality disorder, schizoid personality disorder, and schizotypal personality disorder.[4] Cluster B refers to personality disorders with dramatic, emotional, or erratic characteristics, including antisocial personality disorder, borderline personality disorder, histrionic personality disorder, and narcissistic personality disorder.[5] Cluster C refers to personality disorders with anxious and fearful characteristics, including avoidant personality disorder, dependent personality disorder, and obsessive-compulsive personality disorder.[6] Despite the historical context of using the "cluster" system, there are limitations when approaching personality disorders in this manner, and the 3 groupings are not consistently validated in the literature.[7]

Etiology

There are limited studies focused on the etiology of schizoid personality disorder. However, there are investigations into the etiology of cluster A personality disorders as well as investigations into personality disorders in general. The etiology of personality disorders is complex and multifactorial. Biological factors contribute to the development of personality through multiple means. Temperament is a heritable and innate psychobiological characteristic that significantly contributes to personality development.[8][9] Genetic factors have been attributed as significant contributors to the development of a personality disorder; this was supported by multiple studies that investigated twin, linkage, candidate gene association studies, genome-wide association studies, and polygenic analyses.[8] Twin studies using self-report questionnaires have estimated heritability rates for schizoid personality disorder to be about 30%.[10] Cluster A personality disorders are more commonly found to be biological relatives of an individual with schizophrenia than control groups; however, this was more often associated with schizotypal personality disorder than schizoid personality disorder.[11] Platelet monoamine oxidase levels are associated with sociability levels, with low levels occurring in schizotypal personality disorder but inconsistent findings in schizoid personality disorder.[12] Medical conditions are often associated with personality disorders or personality changes, specifically including those with pathology that may damage neurons. This includes but is not limited to head trauma, cerebrovascular diseases, cerebral tumors, epilepsy, Huntington disease, multiple sclerosis, endocrine disorders, heavy metal poisoning, neurosyphilis, and acquired immune deficiency syndrome (AIDS).[13]  

Children with major depressive disorder who develop a personality disorder are more likely to develop schizoid, avoidant, borderline, or schizotypal personality disorders compared to other adult personality disorders.[14] Additionally, adult prisoners with a childhood history of incarceration were more likely to have schizoid personality traits.[15] 

Psychoanalytic factors also contribute to the development of personality disorders. Psychoanalyst Wilhelm Reich described "character armor" as defense mechanisms that develop with personality types to relieve cognitive conflict from internal impulses and interpersonal anxiety. For instance, those with schizoid tendencies have withdrawal defense mechanisms.[16] From an object relations theory perspective, due to attachment issues during infancy, there is a hypothesized intense fear of intimacy in schizoid behaviors. Therefore, psychological fantasy is common in schizoid personality disorder, including ideas of fantasy lives and imaginary friends who provide internal satisfaction.[1]

Personality is a complex summation of biological, psychological, social, and developmental factors. Each individual's personality is unique, even amongst those diagnosed with a personality disorder. Personality is a pattern of behaviors that an individual uniquely adapts to address constantly changing internal and external stimuli. This is more broadly described as temperament, which has heritable and innate psychobiological characteristics.[8][9] Temperament is further shaped through epigenetic mechanisms, namely, life experiences such as trauma and socioeconomic conditions. These are referred to as adaptive etiological factors in personality development.[17][18] Temperament traits include harm avoidance, novelty seeking, reward dependence, and persistence.

Harm avoidance involves a bias towards inhibiting behavior that would result in punishment or non-reward.[19] High harm avoidance results in fear of uncertainty, social inhibition, shy behavior, and avoidance of danger or the unknown, all of which are characteristics of schizoid personality disorder.

Novelty seeking describes an inherent desire to initiate novel activities that are likely to produce a reward signal.[20] Schizoid personality disorder presents with low novelty seeking, resulting in slow-tempered, uninquiring, isolative, and stoical behaviors.

Reward dependence describes the amount of desire to alter behaviors in response to social reward cues.[21] Individuals with schizoid personality typically have low reward dependence and, as a result, spend most of their time in isolation, with little need for social reward compared to individuals without schizoid personality disorder. 

Persistence describes the ability to maintain behaviors despite frustration, fatigue, and limited reinforcement. Low persistence is consistent with schizoid personality disorder. Low persistence is associated with indolence, inactivity, and ease of frustration. These individuals rarely strive for higher accomplishments.[21][22]

Epidemiology

Schizoid personality disorder is one of the least prevalent personality disorders, with estimates ranging from 0.0% to 4.9% in different epidemiological studies, according to Chapter 6 of The American Psychiatric Publishing Textbook of Personality Disorders: DSM-5 Edition (2014). High-quality and multi-population measures are lacking.[23] A study published in 2005 using DSM-IV criteria estimated that among psychiatric outpatients, the prevalence of schizoid personality disorder was 1.4%.[24] It is not clear whether schizoid personality disorder or traits are more common among men. Schizoid personality disorder is associated with disability in at least one major area of functioning and poor quality of life.[25]  

Pathophysiology

There are limited investigations of neuroimaging and histopathological findings among cluster A personality disorders. One study of 20 subjects with either schizoid personality disorder or schizotypal personality disorder found that subjects had structural alterations of the pyramidal pathway compared to controls. Specifically, subjects presented with greater bilateral white matter volume in the superior corona radiata adjacent to motor/premotor regions. The hypothesized conclusion from these findings suggests that greater volume in motor pathways might relate to cognitive disorganization and negative symptoms in the schizophrenia spectrum illnesses.[26]

History and Physical

Clinically, individuals with schizoid personality disorder seem distant, cold, and aloof, have limited involvement in everyday events, and have little concern for other people. People with schizoid personality disorder live a life of solitude and have a decreased need for social ties, generally only maintaining relationships with first-degree family members. Even with close family members, they do not appear to derive satisfaction from being part of a family or social group.[1] People with schizoid personality disorder prefer solitary activities and hobbies and have limited interest in sexual experiences with other people. Other characteristics include indifference towards approval or criticism by others and rarely exhibiting strong emotions such as anger or joy.

It is essential to inquire how a patient with suspected schizoid personality disorder spends their time and who comprises their social circles. Obtaining a detailed social history may provide insight into how the patient's personality disorder impairs their ability to maintain normal social functioning, including educational struggles and difficulty with maintaining employment or obtaining adequate financial resources. In addition to obtaining a thorough social and personal history from the patient, collateral information is important in diagnosing personality disorders to augment the clinician's view of how an individual reacts to various circumstances over time.[1]

The following should be carefully considered in the psychiatric evaluation, including the mental status examination, of someone suspected of having schizoid personality disorder: 

• Appearance: The patient may be disheveled.
• Behavior: The patient may be uncomfortable and have difficulty making eye contact. The patient may be reluctant to cooperate, aloof, and difficult to engage. 
• Speech: Decreased amount of speech with short answers. No difficulties with speech initiation, volume, or vocabulary.
• Affect: Affective flattening (blunting) is a common feature of schizoid personality disorder
• Thought content: No hallucinations or delusions should be present. If magical content is present, the differential diagnosis should include schizotypal personality disorder. 
• Thought process: The thought process in schizoid personality disorder is usually linear, albeit limited in range and logic. Some disorganization may be present (such as looseness of associations); however, if this is a prominent feature, the differential diagnosis should be broadened to include schizotypal personality disorder and other schizophrenia spectrum illnesses. 
• Cognition: General cognition and orientation are not impaired in schizoid personality disorder but should be evaluated to rule out other psychiatric conditions where this is common, including schizophrenia. 

Evaluation

Diagnosis of a personality disorder depends on longitudinal observation of a patient's behaviors to understand the patient's long-term functioning. Many features of personality disorders overlap with symptoms of acute psychiatric illness.[27] Therefore, personality disorders should generally be diagnosed when there is not a concurrent acute psychiatric condition. An underlying personality disorder may contribute significantly to hospitalizations or relapse of another psychiatric condition (such as a major depressive episode).[28] It may take several encounters to firmly establish the diagnosis of schizoid personality disorder. 

If there is a strong suspicion of schizoid personality disorder, clinicians can utilize the Interpersonal Measure of Schizoid Personality Disorder, a validated and reliable psychometric tool to assess for schizoid personality disorder.[29] For formal diagnosis, the combination of information provided by personal history, collateral information, mental status examination, and psychometric tools can help determine if an individual meets the DSM-5-TR diagnostic criteria for schizoid personality disorder.

DSM-5-TR Criteria for Schizoid Personality Disorder

1. In interpersonal settings, there is a pervasive isolation pattern, limited social relationships, and restricted emotional expression. This pattern of behaviors starts in early adulthood and persists through a variety of contexts, including at least 4 of the following:

   1. No or limited enjoyment of close relationships, including with family. 
   2. Nearly always chooses solitary activities.
   3. Little interest in sexual experiences with others.
   4. Takes pleasure in few activities.
   5. Limited close friendships/relationships other than first-degree relatives.
   6. Indifference to praise and criticism. 
   7. Displays emotional coldness, detachment, and affective flattening.
2. These symptoms do not occur during a course of schizophrenia, bipolar, or a depressive episode with psychotic features. Symptoms are not better explained by autism spectrum disorder or another medical condition.
3. Notably, if schizophrenia develops after a diagnosis of schizoid personality is made, schizophrenia is added as a diagnosis, and schizoid personality disorder is then specified as: "schizoid personality disorder (premorbid)."[30]

Treatment / Management

Individuals with schizoid personality disorder may not recognize their illness and commonly present at the behest of a first-degree relative. Generally, this occurs after maladaptive behaviors have created stress on another rather than internal distress on the part of the individual with schizoid personality disorder. Therefore, it is essential to assess the goals of treatment in each case of schizoid personality disorder. As schizoid personality disorder is unlikely to remit with or without treatment, the focus of treatment may be aimed at reducing interpersonal conflict and stabilizing socioeconomic conditions.[1] Caution should be exercised when considering exposure therapy techniques, such as forcing individuals with schizoid personality disorder into social settings with the goal of improving social skills.

If the patient is not distressed by their isolation, there may not be an indication to pursue such treatments unless the patient desires. Therapists must tolerate a patient's distance while understanding their sense of vulnerability. With this in mind, therapists should use reassurance and a soft, quiet approach without insisting on reciprocal responses. Recognizing a patient's fear of social relationships and respecting their boundaries and fantasies is good for rapport and can be therapeutic.[1] There is no evidence that pharmacotherapy helps treat schizoid personality disorder unless there is a comorbid psychiatric illness. 

Differential Diagnosis

Many behaviors observed in schizoid personality disorder may overlap with symptoms of other psychiatric illnesses, so it is crucial to assess if schizoid personality disorder is occurring in isolation or conjunction with another psychiatric condition.[27] 

Negative symptoms of schizophrenia can overlap with symptoms of schizoid personality disorder. Diminished expression, affective flattening, and alogia are commonly observed with schizoid personality disorder, which may result in similar mental status examination findings between the 2 illnesses. Asociality and anhedonia generally are common in both illnesses. However, apathy is not usually present in schizoid personality disorder but is common in schizophrenia. Positive symptoms of psychosis are not characteristic of schizoid personality disorder. The presence of hallucinations and delusions should raise consideration of a schizophrenia spectrum illness rather than schizoid personality disorder. However, schizoid personality disorder may be a premorbid condition to schizophrenia and has its own DSM-5-TR specifier when this occurs.[30]

Paranoid personality disorder has some similar traits to schizoid personality disorder. However, those with paranoid personality disorder have more social engagement, aggressive verbal behaviors, and more projection-based defense mechanisms rather than the ambivalence and aloofness present in schizoid personality disorder. Individuals with obsessive-compulsive personality disorder and avoidant personality disorder may experience isolation but tend to express more feelings of loneliness compared to an individual with schizoid personality disorder.[4] Individuals with avoidant personality disorder tend to desire to participate in social activities even if they are unable to. Schizotypal personality disorder presents with oddities of thought and communication and with frequent magical thinking, while these symptoms are absent in schizoid personality disorder.  

Patients with autism spectrum disorder have more severe impairment in social interactions than those with schizoid personality disorder, despite people with schizoid personality disorder preferring less social interaction. Additionally, agitation is common in autism spectrum illness but not in schizoid personality disorder.[31]

Pertinent Studies and Ongoing Trials

There have been few studies of schizoid personality disorder since the publication of DSM-III in 1980.[1] In the new era of DSM-5-TR and the ever-shifting social landscape, there is a need for detailed case reports and case series that highlight how schizoid personality disorder presents in modern clinical practice. There are a few case reports describing violent behavior perpetrated by individuals with schizoid personality disorder,[32][33] which further highlights the need for research. 

There are significant limitations with the ongoing use of the "cluster" system for personality disorders as described in the various editions of the DSM. Despite behavioral patterns that have been classified into syndromes/personality disorders, the uniqueness of each person remains problematic for the diagnosis of and research into specific personality disorders.[7] Experts in the field of personality disorders have suggested switching to a dimensional model of personality rather than a cluster model. The proposed dimensional models generally describe temperament, utilization of defense mechanisms, and identification of pathological personality traits.[34] Although the DSM-5-TR did not incorporate these recommendations due to the radical change in clinical usage, the paradigm will likely shift in the coming decades as further research solidifies concomitantly with evolving clinical guidelines. DSM-5-TR acknowledged the transition to a new approach and identified a hybrid dimensional-categorical model in the "Emerging Measures and Models" section.

Prognosis

There are limited studies regarding the prognosis and long-term outcomes of individuals with schizoid personality disorder. A 2-year follow-up study found that individuals with schizoid personality traits and antisocial personality traits had the highest degree of stability compared to other personality traits.[35] An investigation using DSM-III era criteria found that people with schizoid personality disorder (along with antisocial, borderline, histrionic, and avoidant personality disorders) were more likely to have long-term impairment of global functioning compared to the other personality disorders.[36] Schizoid personality disorder is unlikely to resolve either on its own or with treatment. Interventions to optimize quality of life, including reducing psychiatric comorbidity and stabilizing socioeconomic factors, may improve the prognosis of schizoid personality disorder. 

Complications

Schizoid personality disorder may sometimes be a precursor of schizophrenia. However, not all cases of schizoid personality disorder evolve into schizophrenia.[30] Other personality disorders may be comorbid with schizoid personality disorder, most commonly paranoid, schizotypal, and avoidant personality disorders. Substance use disorders are common among personality disorders, but there is limited evidence on which personality disorders pose the most risk for a substance use disorder.[37] People with personality disorders have an increased likelihood of suicide and suicide attempts compared to those without personality disorders, and individuals with schizoid personality disorder should be screened regularly for suicidal ideation.[38]

Deterrence and Patient Education

The treatment of schizoid personality disorder hinges on developing and maintaining a therapeutic rapport. Therapists should offer reassurance and should neither expect nor insist upon a patient with schizoid personality disorder providing reciprocal responses. Patients should be encouraged to articulate any symptoms they would like addressed or any psychosocial stressors the treatment team can help alleviate. Clinicians should refrain from focusing on reducing isolative behaviors if the patient is not in clinical distress from these symptoms. Encouraging patients to utilize support networks through any social relationships is desirable. Involving the patient's family is a way of monitoring for decompensation. The therapist can educate the patient and family about ways to stabilize the patient's living situation.[30] Utilizing standardized assessments for quality of life may reveal ways to optimize the patient's ability to function.[3]

Enhancing Healthcare Team Outcomes

The diagnosis and treatment of schizoid personality disorder is complicated and ultimately an area open for psychiatric research. As diagnostic and treatment models shift away from a "cluster" system and towards a dimensional model of personality disorders, the implications for clinical practice are unclear. When a treatment team suspects that a patient has schizoid personality disorder, a thorough psychiatric evaluation, including a comprehensive history in conjunction with collateral information, is recommended before formally diagnosing schizoid personality disorder. The treatment team should educate family members about monitoring individuals with schizoid personality disorder for any positive symptoms of psychosis (such as delusions or hallucinations) that may indicate the development of schizophrenia.[30] It is important to include the patient's perspective and collaborate with the patient in determining the appropriate goals of care to prevent overmedicalization or iatrogenic harm to a patient who may not be suffering from any treatable symptoms. Collaboration with psychologists, psychiatrists, social workers, psychiatric-mental health nurse practitioners, psychiatric nurses, primary care practitioners, and family to optimize the psychosocial factors in a patient's life can offer stability to individuals with schizoid personality disorder. Treatment teams encountering cases of schizoid personality should consider publishing detailed case descriptions (Oxford CEBM evidence level 5), along with the treatments and psychosocial factor optimizations attempted and their outcomes.

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Disclosure: Kamron Fariba declares no relevant financial relationships with ineligible companies.

Disclosure: Nandhini Madhanagopal declares no relevant financial relationships with ineligible companies.

Disclosure: Tyler Torrico declares no relevant financial relationships with ineligible companies.

Disclosure: Vikas Gupta declares no relevant financial relationships with ineligible companies.