Encyclopedia of Autism Spectrum Disorders

Living Edition
| Editors: Fred R. Volkmar

Personality Disorders

  • Bram SizooEmail author
  • Ernst Horwitz
Living reference work entry
DOI: https://doi.org/10.1007/978-1-4614-6435-8_1548-3


Short Description or Definition

Personality disorders in autism refer to comorbidity (co-occurring psychiatric disorders). In medicine, comorbidity is relatively straightforward because it mostly concerns well-defined disease entities with known causes (e.g., a fractured leg co-occurring with diabetes). In psychiatry, however, disorders are defined as clusters of signs and symptoms (syndromes), with complicated and uncertain causal pathways. As a consequence, psychiatric disorders show a considerable overlap. This makes it difficult to decide whether symptoms have to be ascribed to either disorder A or disorder B (differential diagnostics) or to both A and B (comorbidity). This issue is important for achieving diagnostic clarity and for managing treatment.

This chapter deals with the dilemma posed when signs and symptoms point to a personality disorders (PD) as well as to an autism spectrum disorder (ASD).


Autism Spectrum Disorders (ASD)

In the previous version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), pervasive developmental disorders were subtyped by the Autistic Disorder (AD), Asperger’s Syndrome (AS), and the Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). In the new DSM version (DSM-5), these subcategories have been replaced by a single category: Autism Spectrum Disorder.

For the purpose of this chapter, it is important to note that whereas DSM-IV required an onset of symptoms before the age 3 years for the autistic disorder, in DSM-5 this restriction is less strict. Symptoms must be present in early childhood but may not become fully manifest until social demands exceed limited capacities, mostly in adolescence. ASD is diagnosed when there are persistent deficits in social communication and social interaction across contexts and restricted, repetitive patterns of behavior, interests, or activities.

Personality Disorders (PD)

In DSM-IV and DSM 5, 10 categorically defined personality disorders are characterized by enduring and pervasive patterns of inner experiences and behavior (manifested in the areas cognition, affectivity, interpersonal functioning and impulse control); the onset of the patterns can be traced back to adolescence or early adulthood (American Psychiatric Association [APA] 2000). The categorical nature of personality disorders in DSM-IV poses clinicians with classification problems when symptoms are subtle or can also be explained (but not necessarily better) by other disorders or comorbid conditions.

Personality Disorder and/or Autism Spectrum Disorder

The relationship between personality disorders and symptom disorders is complex. Different models have been postulated to describe the shared etiological and pathophysiological factors, such as the predisposition/vulnerability model and the complication/scar model. A promising approach is the model which describes the development and co-occurrence of syndrome and personality disorders as psychobiological in scope (Dolan-Sewell et al. 2001). The Cloninger model (see further below) is an example of this conceptualization. The relationship between PDs and ASD is even more complicated because of the developmental nature of both disorders. While the onset of PDs is theoretically in early adulthood, the first manifestation of behavioral maladaptive patterns occurs in many instances much earlier on in life. In the diagnostic process of distinguishing PD from ASD, untangling the pathways of symptoms along the lifespan, especially in retrospect, can be a daunting task.

Comorbidity is defined by the presence of two or more disorders present at the same time (Angold et al. 1999; Goldsmith 1999). DSM-IV, however, dictates that if a consistent pattern of experiences or behavior can be better ascribed to the expression or consequence of another psychiatric disorder (e.g., ASD), a PD cannot be diagnosed.

A practical answer to the comorbidity question is that if the clinical presentation of ASD is dominated by major symptoms that would be left underreported if only ASD were classified, it is possible to speak of comorbidity without violating the classification rules. So by classifying a comorbid personality disorder, the clinician draws attention to the complexity of the presentation requiring more than the usual ASD treatment.

However, for clinical purposes, it can be worthwhile to assess personality pathology and traits regardless of whether or not a personality disorder is classified. This is much in line with the proposed DSM-5 methodology.


There is no reliable data on the prevalence of personality disorders in autism. This is partly due to the earlier mentioned classification rules discouraging diagnosing both at the same time. Like in ASD, assessment of PDs with the “golden standard” (semistructured interviews) is time consuming.

Studies that examined personality profiles in adults with ASD with the Temperament and Character Inventory (Cloninger et al. 1993) show that ASD is characterized by high harm avoidance compared with the norm population, pointing to worrying and pessimistic individuals who are tense in unfamiliar situations or with strangers. In addition, patients with ASD had low scores for reward dependence, indicating little sentimentality and social attachment, and little dependence on approval of others (Anckarsäter et al. 2006; Sizoo et al. 2009; Söderstrom et al. 2002). The clinical significance of the temperament and character patterns found in patients with ASD is that these profiles sketch in a broad outline the nature and problematic quality of interpersonal relationships between them and others. Other studies showed similar patterns using other instruments like the Autism Spectrum Quotient and the Neuroticism Extraversion Openness Personality Inventory Revised (NEO-PI-R) (Austin 2005; Wakabayashi et al. 2006; Strunz et al. 2015).

Murphy et al. found that particular personality traits may also aggregate in the family members of autistic individuals (broad autism phenotype) and furthermore that some of these traits may be a manifestation of the liability to autism (Murphy et al. 2000; Piven et al. 1997).

In summary, little is yet known about the epidemiology of comorbidity patterns with ASD and PD.

Natural History, Prognostic Factors, Outcomes

In general, comorbidity with personality disorders becomes manifest in adolescence. In the current system of DSM 5, ASD often presents with symptoms that also address the criteria for a PD. This may cause confusion, however, when the first symptoms of ASD occur in adulthood. ASD can then be mistaken for a personality disorder, and vice versa, depending on the focus of the clinical assessment. Intelligence is an important prognostic factor in ASD (Seltzer et al. 2004), meaning that children with higher IQs have a better functional outcome in adulthood than those with lower IQs. Although it is possible that this is also the case in ASD comorbid with PD, clinical practice indicates that there are adults with ASD and high IQs whose functioning is severely hampered by comorbid personality traits. The outcome of ASD with PD has, however, not been studied in a systematic way. The clinical evidence suggests that, like in other symptom disorders, the presence of a PD in ASD increases the burden.

Clinical Expression and Pathophysiology

In ASD, impaired information processing in the brain is especially invalidating in complex situations involving social interaction and emotional communication. In addition, the insight in mental processes of others, but also the self, is often limited because of an impaired intuitive understanding of social relationships and contextual conventions. This implies that people with ASD require more time to evaluate (social) situations because cognitive compensation strategies are utilized to understand what people without ASD know without consciously thinking (Frith 2003).

The developing personality is also influenced by environmental factors, like in ASD. In this respect, the presence of ASD contributes to a pertinent environmental factor because impaired communication and difficulty interpreting social contexts lead to negative reactions of others, which in turn lead to avoidance, anxiety, or a lack of flexibility. The adverse experiences with social interaction may accentuate schizoid, avoidant, or dependent traits when looked at from the personality perspective. The impaired information processing and difficulty with correctly evaluating social contexts in ASD make a clear demarcation between reality and fantasy difficult, enhancing schizotypal personality traits (Towbin 2005). Early trauma and insecure attachment are risk factors for developing a borderline personality disorder (Fonagy and Bateman 2008). When a person with autism is exposed to these risk factors, the resulting phenotype can resemble both disorders. The overlap in phenomenology of ASD and borderline personality disorder, both characterized by altered social cognition, has been noted for some time (e.g., Dudas et al. 2017).

On the other hand, extremes in temperament that are distinctive of personality disorders can color the clinical picture of ASD. Social typologies used in ASD like “active but odd” are in part an expression of personality traits.

Evaluation and Differential Diagnosis

In the assessment, a reliable developmental history is mandatory to diagnose or rule out ASD and to find evidence for causal factors that could contribute toward the development of the personality disorder. An assessment of personality should also be a part of the ASD assessment. Early trauma, insecure attachment (Fonagy and Bateman 2008) in the case of borderline personality disorder and an arrested developmental phase in the case of narcissistic personality disorder (Fernando 1998) are among the descriptive etiological hypotheses.

The assessment can lead to a classification of ASD and/or a PD. However, more informative is a comprehensive descriptive diagnosis in which traits and behavior, neuropsychological and other impairments, and an overview of contributing (causal) factors combine to serve as an explanatory model for the patient, his close relatives, and the clinician.


In case of ASD comorbid with a PD, the effect of programs for personality disorders can be seriously reduced if no account is taken of the impairments that accompany ASD. For example, exposure therapy for social anxiety in an avoidant PD will be less effective when the origin of the avoidance is rooted in a fundamental inability to understand the other in social encounters, as in ASD. In fact, it may for some patients even be considered undesirable to change the avoidant behavior in autism as this could, in the worst case, deteriorate functioning by inducing more (disturbing) social stimuli.

In ASD comorbid with borderline personality disorder, clinical in-patient settings can undermine the autonomy of the individual, leading to serious regression with self-harm and aggressive behavior. Here, the clinical dilemma is between insisting that the patient takes her own responsibility (autonomy) while bearing in mind the cognitive and affective impairments resulting from ASD that prevents her from fully taking this self-responsible stance.

There is currently no systematic evidence to guide treatment of ASD comorbid with a PD or with prominent personality traits. Understanding the impairments (and adaptive aspects) of the individual is the best approach to tailor treatment. This requires a clinician to be familiar with treatment programs for personality disorders and to study the ins and outs of ASD in order to be able to adopt the content or pace of the programs targeting the comorbid PD. Unadjusted PD treatment in patients with ASD probably has a high failure rate, although this had not been systematically studied.

See Also

References and Readings

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© Springer Science+Business Media LLC 2018

Authors and Affiliations

  1. 1.PsychiatryCenter for Developmental DisordersDeventerThe Netherlands
  2. 2.Department of PsychiatryGroningen University Medical CenterGroningenThe Netherlands