Schizoid Personality Disorder
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Schizoid personality disorder is a personality disorder that is associated with social detachment, emotional aloofness, and significant clinical impairment. Diagnostic criteria include a lack of close relationships, the preference for solitary activities, little interest in sexual experiences with another person, little interest in other activities more broadly, a lack of close friends other than first-degree relatives, indifference to praise or criticism, emotional coldness, detachment, and flattened affect.
Schizoid personality disorder (SZPD) is a mental disorder characterized by social detachment and affective flatness. SZPD is one of the most under-researched and poorly understood personality disorders within the DSM-5. Consequently, accurate prevalence estimates for SZPD are scarce, but they tend to range from 1% to 5% of the general population (American Psychiatric Association [APA] 2013). There has also been a significant amount of debate regarding the validity of the diagnosis; given its low prevalence rate and concerns that the SZPD diagnosis does not represent a distinct diagnostic construct, the DSM-5 Task Force recommended eliminating SZPD from the latest edition in its entirety. However, proponents of the diagnosis argued that it would lead to a loss of significant clinical understanding when diagnosing and treating those with schizoid personality features. Consequently, SZPD remains a diagnosis within the latest edition of the DSM. This entry will begin by providing an overview of the current DSM-5 diagnostic criteria for SZPD. A historical examination of SZPD throughout the editions of the DSM will also be provided. We will then review the clinical characteristics associated with SZPD. Finally, we will conclude by highlighting important treatment considerations for the disorder, with the caveat that more research is needed to fully understand SZPD.
Current Diagnostic Criteria for Schizoid Personality Disorder
Broadly speaking, the Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition (DSM-5; American Psychiatric Association [APA] 2013) defines personality disorders as enduring patterns of internal experiences and behaviors that are outside of the individual’s cultural context. Consequently, personality disorders are considered to be chronic and rigid disorders, which often lead to clinically significant distress and/or impairment in activities of daily life. Though a controversial diagnosis, modern conceptualizations of SZPD highlight a lack of and detachment from close social or familial relationships and the restricted range of emotional expression as defining features of this debilitating diagnosis. SZPD is often included as a “Cluster A” personality disorder, which also includes paranoid personality disorder and schizotypal personality disorder. Individuals with these personality disorders often appear odd or eccentric to others, and they tend to experience deficits in social functioning.
To meet DSM-5 (APA 2013) criteria for SZPD, an individual must be at least 18 years of age and demonstrate four or more of the following seven diagnostic criteria: (1) neither desires nor enjoys close relationships, including being part of the family unit; (2) almost always chooses solitary activities; (3) has little, if any, interest in sexual experiences with another person; (4) takes pleasure in few, in any, activities; (5) lacks close friends or confidants other than first-degree relatives; (6) appears indifferent to praise or criticism by others; and (7) shows emotional coldness, detachment, or flattened affect. The aforementioned characteristics of the disorder must not occur exclusively during the course of schizophrenia, bipolar disorder, depressive disorder with psychotic features, or autism spectrum disorder. Symptoms must also not be the result of the physiological effects of a medical condition.
Careful consideration should also be given when making a differential diagnosis, as SZPD shares similar characteristics with other mental disorders. Although an individual with SZPD may experience a brief psychotic episode, SZPD may be distinguished from delusional disorder, schizophrenia, bipolar disorder with psychotic features, and depressive disorder with psychotic features, as these diagnoses must include an episode of enduring psychotic symptoms (APA 2013). Evidence of SZPD must also exist prior to the development of any psychotic symptoms, and symptoms must remain once the psychosis has remitted. SZPD may also be difficult to distinguish from autism spectrum disorder, as both are generally characterized by social deficits. The DSM-5 (APA 2013) suggests that individuals with autism spectrum disorder likely experience greater difficulties in social functioning, as well as engagement in stereotyped and/or repetitive behaviors (e.g., lining up or flipping objects), as compared to those individuals diagnosed with SZPD.
SZPD also shares diagnostic characteristics with other personality disorders. For example, flattened affect and social isolation are also characteristics of schizotypal personality disorder and paranoid personality disorder. However, SZPD is distinguished from schizotypal personality disorder by a lack of odd cognitive and perceptual disturbances. SZPD may also be distinguished from paranoid personality disorder by the absence of suspiciousness and paranoia in SZPD. While social isolation is characteristic of both SZPD and avoidant personality disorder, those with avoidant personality disorder tend to suffer from a fear of embarrassment in front of others, as well as subsequent fears of rejection. In contrast, individuals with SZPD do not appear to outwardly desire any type of social connection or intimacy. In addition, individuals with obsessive-compulsive personality disorder may experience social isolation as a result of their devotion to work and distress surrounding the experience of affect, but unlike those with SZPD, individuals with obsessive-compulsive personality disorder possess the capacity for social connection and intimacy. Finally, the DSM-5 (APA 2013) reminds the clinician that, while someone may appear to be a loner or detached from others, an individual diagnosed with SZPD must demonstrate inflexible and maladaptive personality traits, which results in a significant amount of distress experienced by the individual or considerable impairment in activities of daily living.
A Historical Overview of SZPD in the DSM
The term schizoid is originally derived from the Greek word schiz, meaning, “to split;” as such, the term schizoid suggests that there are aspects of the individual’s personality that are “split off” or detached from one’s surroundings or reality (Hopwood and Thomas 2012). The term “schizoid” was first introduced to the psychiatric and medical community by psychiatrist Eugen Bleuler in 1908. At that time, he described the schizoid individual as having a limited ability to express their emotions, as well as a tendency to oscillate between emotional sensitivity and emotional flatness (Hopwood and Thomas 2012; Mittal et al. 2007). As outlined by Peralta and Cuesta (2011), Bleuler conceptualized psychotic psychopathology as being on a continuum, which ranged from the less-severe schizoid personality and potentially dormant schizophrenia to schizophrenia proper.
Unlike other personality disorders, SZPD has been included in all five iterations of the DSM. The first edition of the DSM, which was published in 1952, included short paragraphs that outlined the characteristics of each disorder, generally not exceeding 200 words; consequently, there was significant room for interpretation by clinicians, which resulted in problems related to diagnostic reliability (Blashfield et al. 2014). Early diagnostic conceptualizations of SZPD were based upon the writings of German psychiatrist Emil Kraepelin who viewed features associated with the schizoid personality as an antecedent to the development of an underlying psychotic disorder (e.g., schizophrenia). At that time, diagnostic criteria for SZPD included the avoidance of intimate relationships with others, an inability to express hostility or aggression directly, and “autistic thinking” (i.e., a preoccupation with inner thoughts or internal experiences). SZPD traits were believed to develop in childhood, based on observations of children with excessive shyness, quietness, obedience, and sensitivity. It was also believed that children with SZPD characteristics became increasingly withdrawn, isolative, and eccentric as they reached puberty and beyond.
With the introduction of the DSM-II (APA 2013), the diagnostic criteria for the schizoid personality remained largely unchanged. As such, diagnostic criteria included shyness, sensitivity, reclusiveness, avoidance of close relationships, and eccentric behavior. Much like the DSM-I, autistic thinking, as well as an inability to express hostility and aggression, remained important components of the disorder. The DSM-II also specified that individuals with SZPD tend to react to upsetting events with a sense of disengagement or emotional flatness.
In 1980, psychiatry moved toward a new conceptualization and understanding of psychiatric diagnosis and published the DSM-III (APA 1980). Prior to the development of the DSM-III, mental disorders were thought of in dimensional terms, heavily influenced by the psychoanalytic and psychodynamic tradition. However, by the 1980s, psychiatry as a discipline began to emphasize the importance of empirical evidence in the diagnosis of mental disorders. Mayes and Horowitz (2005) provided a historical rationale for this new understanding of mental disorders: “The DSM-III emphasized categories of illness rather than blurry boundaries between normal and abnormal behavior, dichotomies rather than dimensions, and overt symptoms rather than underlying etiological mechanisms” (p. 250). In other words, psychiatry wished to communicate clear criteria for what was thought of as a mental disorder and move away from vague, psychoanalytic concepts as explanations for the roots of dysfunction (Blashfield et al. 2014).
Psychiatry consequently transitioned from a Kraepelinian understanding of SZPD (i.e., as a precursor to later psychotic illness) and instead drew heavily upon the work of another German psychiatrist, Ernst Kretschmer (Hopwood and Thomas 2012; Millon 1981). There was significant overlap between SZPD and avoidant personality disorder at that time, and the DSM-III (APA 1980) aimed to distinguish the two disorders as distinct constructs. As a result, those involved in the development of DSM-III viewed SZPD from a Kretschmerian perspective, who conceptualized schizoid personality as two distinct subtypes: the hyperaesthetic subtype, which was characterized by uneasiness (similar to what is now considered avoidant personality disorder), and the anesthetic subtype, which was characterized by flattened affect (similar to modern conceptualizations of SZPD; Hopwood and Thomas 2012). While the SZPD diagnosis had originally been used as a diagnostic category to understand all seemingly odd or isolative behaviors, the new DSM-III conceptualization of SZPD focused on the emotional and interpersonal indifference that characterizes modern conceptualizations of the disorder. SZPD was subsequently differentiated from schizotypal personality disorder and avoidant personality disorder, and the DSM-III criteria for SZPD included a lack of interest in relationships with others, the preference to remain alone, limited sexual interest, a lack of pleasure or interest in activities more broadly, a lack of close friendships or social connections with others, emotional detachment, and indifference to rejection, praise, or criticism.
The diagnostic criteria of SZPD from DSM-III to DSM-IV remained largely unchanged, with the exception of one minor alteration: indifference to rejection was removed, as it was believed that the phrase was too broad and potentially left room for a significant amount of clinician interpretation (Hopwood and Thomas 2012). However, as preparations began for the release of the fifth edition of the diagnostic manual, there was a significant amount of debate surrounding the SZPD diagnosis among those on the DSM-5 Task Force. Given its low prevalence rate and concerns that SZPD does not represent a distinct diagnostic construct, it was recommended that SZPD be eliminated as a diagnosis from the latest edition of the DSM, as the SZPD diagnosis demonstrated poor psychometric qualities as a distinct construct.
To address validity and reliability concerns surrounding the diagnosis, the DSM-5 Task Force argued that schizoid personality features could be adequately captured through dimensional ratings of five personality disorder types (i.e., antisocial, avoidant, borderline, obsessive-compulsive, and schizotypal) and six personality trait domains (i.e., negative emotionality, introversion, antagonism, disinhibition, compulsivity, and schizotypy). For a thorough discussion and examination of this new model of personality assessment, see Waugh et al. (2017). Recent research has supported this alternative framework for SZPD. For example, Hummelen et al. (2015) found that the psychometric properties of the traditional conceptualization of the SZPD diagnosis were quite poor. However, when examined as a dimensional construct, SZPD traits fared better and were relatively distinct from other personality disorder criteria. In fact, the factor structure reported by Hummelen and colleagues (i.e., intimacy avoidance, withdrawal, and restricted affectivity) was in congruence with the alternative model for personality disorders proposed for DSM-5. Similarly, Ahmed et al. (2012) found that when SZPD was examined as a dimensional construct, it outperformed a categorical conceptualization of the disorder and significantly predicted social, mental, and emotional health measures.
Those who wished to retain the diagnosis of SZPD argued that there were, in fact, features of the construct that would not be adequately captured by the alternative model, and the removal of the diagnosis of SZPD would likely result in the loss of a nuanced understanding of a disorder that causes some individuals a significant amount of clinical distress. For example, it has been found that the inability to experience pleasure from social situations is predictive of SZPD, while the need to belong is associated with avoidant personality disorder (Winarick and Bornstein 2015). As such, it appears as though the underlying interpersonal mechanisms of each disorder are opposed to one another: one disorder is associated with a lack of a desire to form close relationships (i.e., SZPD), while the other disorder is associated with the desire to connect with others (i.e., avoidant personality disorder). Moreover, characteristics associated with the odd/eccentric personality disorders have been associated with the development of psychotic illnesses in adulthood, such as schizophrenia (Ekstrøm et al. 2006). Therefore, the ability to accurately assess for the presence of SZPD symptoms may have important implications for early intervention and treatment of psychotic illness.
Research has also addressed the importance of assessing for the presence of schizoid personality features using empirically validated assessments. For example, Kosson et al. (2008) developed the Interpersonal Measure of Schizodia (IM-SZ), in order to assess for the interpersonal aspects of SZPD. The authors examined the measure using two samples of incarcerated individuals. Across the two studies, the authors found that the measure demonstrated adequate reliability. In addition, it was found that the IM-SZ correlated with other measures of schizoid personality pathology in the expected directions. Therefore, it appears as though aspects of SZPD can be meaningfully measured using easy-to-administer assessment techniques, which suggests that the diagnosis is in fact a distinct clinical construct. Ultimately, the DSM-5 Task Force retained the DSM-IV diagnostic criteria for SZPD and moved the proposed alternative model to Section III (i.e., disorders that require further study) of the manual.
Clinical Characteristics of SZPD
Historically, SZPD is one of the least studied personality disorders within all iterations of the DSM (Treibwasser et al. 2012). Consequently, prevalence estimates of the disorder within the general population may not be entirely accurate. It is also not surprising that individuals with this disorder rarely present for treatment or participate in empirical investigations due to the social functioning deficits associated with SZPD. As such, the field’s understanding of the disorder is severely limited and heavily dependent upon case examples (Novović et al. 2013). Therefore, it is difficult to determine whether the identified characteristics of the disorder generalize to all individuals with schizoid traits or SZPD or just to those who have been extensively studied for case examples.
Despite the lack of research associated with the disorder, some prevalence estimates exist within the literature. As outlined in the DSM-5 (APA 2013), the National Comorbidity Survey Replication suggested a prevalence rate of 4.9% within the general population, while National Epidemiologic Survey on Alcohol and Related conditions (2001–2002) found a prevalence rate of 3.1% within the general population. However, earlier research reported a prevalence rate of less than 1% in the general population (Weissman 1993). More recent empirical work echoes these earlier results. Specifically, Hummelen et al. (2015) examined the prevalence of SZPD within a sample of 2,619 patients and found only 19 patients (or 0.7% of the sample) who met diagnostic criteria for SZPD. Based upon the available evidence, it is likely that the prevalence rate of SZPD ranges from approximately 1 to 5% in the general population, though further epidemiological research is warranted.
Much like the prevalence estimates for SZPD, the demographic and clinical characteristics associated with SZPD are also poorly understood. For example, very little is known about the developmental origins of SZPD in childhood or adolescence (Esterberg et al. 2010). Although a personality disorder cannot be diagnosed prior to the age of 18, it is not uncommon for problematic personality traits to be apparent from a very young age. With regard to SZPD, it is believed that childhood features include isolation, a lack of relationships with same-aged peers, poor achievement in school, and potential teasing or bullying by others (APA 2013). These traits tend to remain stable, and they are known to lead to the development of SZPD, schizotypal personality disorder, or schizophrenia in adulthood (Esterberg et al. 2010; Wolff et al. 1991). Major depressive disorder in childhood and/or adolescence also appears to be predictive of SZPD in adulthood (Ramklint et al. 2003). There also appears to be a significant genetic component of SZPD; Kendler et al. (2006) assessed the odd/eccentric personality disorders in 1,386 young adult twin pairs using the Norwegian Institutive of Public Health Twin Panel and concluded that SZPD had a genetic liability of 26%. However, further research is needed to determine the developmental trajectory of schizoid traits.
In adulthood, SZPD is more often diagnosed in men than in women (APA 2013; Hummelen et al. 2015). SZPD has also been associated with a significant amount of clinical impairment. For example, as part of a larger longitudinal study, Ullrich, Farrington, and Cold (Ullrich et al. 2007) examined the DSM-IV personality disorders and their associations with life success among 304 men at age 48. Within this sample, 6.3% of the men met criteria for a diagnosis of SZPD. Correlational analyses revealed that SZPD was significantly negatively correlated with successful intimate relationships, status, and wealth. Similarly, Cramer et al. (2006) examined the relationship between quality of life and personality disorders within a large sample of adults (N = 2053). Individuals with avoidant, schizotypal, paranoid, schizoid, and borderline personality disorders demonstrated the greatest reductions in quality of life.
As SZPD is characterized by social detachment, chronic disconnection from the social world may lead to a retreat into one’s internal fantasy world, resulting in brief psychotic or manic episodes (Beck and Freeman 1990). Chadwick (2014), a psychologist and author, recently shared his own experience of being diagnosed with SZPD in a peer-reviewed journal article. He described a significant amount of time immersed in his own thoughts, thus leading to difficulties with participating in activities of daily living, as well as a lack of meaningful attachment to others. For Chadwick, the most distressing aspect of being diagnosed with SZPD is others’ perceiving him as arrogant when in fact he feels a deep inner inferiority as compared to others, due to his social withdrawal. As other case examples suggest, SZPD often leaves the individual feeling misunderstood by others, which likely exacerbates the already difficult interpersonal symptoms associated with the disorder.
Extensive literature describing the clinical characteristics of the schizoid personality exists within modern psychoanalytic and psychodynamic theory. For example, McWilliams (2011) writes that schizoid individuals are extremely sensitive to interpersonal stimulation, and they retreat when they feel as though they are in danger of being engulfed by others. McWilliams was also a significant contributor to the Psychodynamic Diagnostic Manual (PDM 2006), which suggests that schizoid pathology operates on a continuum, from the profoundly troubled individual to the higher functioning individual. In order to cope with their intense fears of engulfment by others, schizoid individuals might isolate themselves, either by physically remaining alone or by retreating into an internal fantasy world. Consequently, schizoid individuals may appear distant and/or cold to others, yet they may also experience a deep sense of yearning for interpersonal connection. Their behavior may also appear odd or socially inappropriate to those around them. In addition, individuals with schizoid personality traits tend to be keenly aware of their internal processes, which may actually be unconscious or difficult to understand for those without schizoid pathology. Clinicians within the psychoanalytic or psychodynamic tradition suggest that individuals with schizoid personality traits tend to intensely feel their emotions, rather than simply deny the existence of emotion. Consequently, these individuals may also feel as though they must suppress their emotions, as a way to cope with affect and avoid feeling overwhelmed.
Treatment Considerations for SZPD
There are few published empirical studies that have examined the effectiveness of treatment for SZPD (Thylstrup and Hesse 2009; Treibwasser et al. 2012), or for the odd/eccentric personality disorders in general (Blom and Colijn 2012). Thus, little is known about the therapeutic interventions that could effectively target the symptoms of SZPD. Based on clinical experience, however, Thylstrup and Hesse (2009) offered several concrete treatment recommendations for working with patients diagnosed with SZPD. First, the authors suggested that, in order to effectively establish a working alliance, special attention must be given to the schizoid patient’s desire for “emotional space” (p. 163). These patients may need more time to develop a sense of trust with the therapist, due to their underlying and unconscious fears of being consumed by others. Second, the authors suggested using a non-confrontational approach in the beginning stages of treatment, as doing so allows the patient to avoid feeling smothered or judged by the therapist. Third, the authors also suggested providing the patient with psychoeducation regarding schizoid personality features and how these features may impact the patient’s overall functioning in the world. Fourth, the authors cautioned therapists to monitor their own responses to the patient, as the psychopathology associated with SZPD may evoke a sense of ineffectiveness in the therapist. They also encouraged the therapist to be vigilant for the development of any psychotic symptoms in their patient with SZPD, as the disorder is often associated with brief psychotic experiences, or the development of a later psychotic disorder. Thylstrup and Hesse (2009) also recommended that the schizoid patient be referred for group psychotherapy as an adjunctive treatment, so that the patient may learn to interact with others and reduce their fears of intimacy in a safe and supportive environment. It is also important to note that even individual psychotherapy allows for the development of an emotional relationship between therapist and patient that may serve as a model for subsequent fulfilling relationships outside of the context of therapy. Finally, the authors also recommended a medication consultation with a psychiatrist to treat the patient’s social anxiety in conjunction with psychotherapy.
Much of what is known about the treatment of SZPD is drawn from the modern psychoanalytic and psychodynamic literature. Hess (2016), for example, highlighted the challenges of working with the schizoid patient, including the schizoid patient’s difficulty in relating to others, emotional detachment, and a lack of interest in exploring one’s internal experience. Lewin (2015) noted the effectiveness of capacity learning as an intervention for the schizoid patient, where the therapist lends his or her belief that growth is possible to the patient implicitly, which fosters the patient’s ability to eventually believe in his or her own capacity for change. In addition, it is not uncommon for individuals with SZPD to also be creative and intelligent individuals; thus, the therapist may also consider the inclusion of literature, art, and music in the treatment, in order to engender improved emotional communication in psychotherapy.
Finally, the PDM (2006) suggests that those with schizoid personality traits tend to do best in psychotherapy when there is an opportunity for emotional intimacy, accompanied by respect for the patient’s need for space. McWilliams (2011) noted that the schizoid patient approaches therapy in much the same way they approach all interpersonal interactions, with an enduring fear that the other person will engulf them. As a result, the therapist may experience difficulty entering and understanding the patient’s internal world. McWilliams also suggested that the therapist should find the delicate balance between curiosity about the schizoid patient’s world, without causing undue fears of invasion.
In sum, schizoid personality disorder (SZPD) is characterized by a detachment from the social environment and emotional flatness. During the development of the DSM-5, there was significant debate regarding the diagnosis’ validity as a distinct diagnostic construct. Proponents of the SZPD diagnosis argued that a significant amount of clinical nuance would be lost if SZPD were to be eliminated from the diagnostic manual. Consequently, it was decided by the DSM-5 Task Force to retain the diagnosis in the most current edition of the manual. Despite this decision, SZPD remains a poorly understood diagnosis, likely due to a lack of empirical investigation into the characteristics of the disorder, as well as a hesitation by those with the disorder to present for treatment or participate in research. Although few treatment studies exist, professionals with experience treating the disorder suggest that the therapist should honor the schizoid patient’s wish for emotional space, as they have a tendency to become overstimulated during interpersonal exchanges. Doing so also allows for the development of a strong working alliance between patient and therapist. Psychoeducation as well as group psychotherapy also appear to be important aspects of the treatment of SZPD. However, more research is needed to understand and effectively treat this distressing and isolating personality disorder.
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