Narcissistic Personality Disorder and Autism (3):

Prevalence and comorbidity

ASDs are known to exhibit a high degree of heterogeneity in both clinical presentation and outcomes. Differences in personality profiles, as well as the presence of comorbidities with Personality Disorders (PDs), can significantly impact various aspects of life for autistic individuals. These include social adaptability, quality of life, internalising symptoms, and employment rates (Schwartzman et al. 2016; Rodgers et al. 2018; Lodi-Smith et al. 2019; Grella et al. 2022).

Prevalence

The existing literature on the co-occurrence of NPD and ASD indicates a limited rate of comorbidity between ASD and NPD (Rinaldi et al. 2021, Vuijk et al. 2018). In fact, it appears that all Cluster B Personality Disorders are rarely diagnosed alongside ASD. In particular, NPD is rarely identified as a co-diagnosis with ASD, with reported co-occurrence rates ranging from 0% to 6.4% (Anckarsäter et al.2006; Lugnegård et al. 2012). However, although the reported co-diagnosis rates are low, it is common to encounter diagnostic doubts in clinical practice when clinical suspicions of psychopathological and behavioural features in ASD that resemble NPD presentation often arise during initial diagnostic assessments.

The matter is, the Diagnostic and Statistical Manual of Mental Disorders (DSM) primarily focuses on grandiose psychological experiences and behaviours (Pincus et al. 2009; Ronningstam 2009), which may impact the reported prevalence of NPD in various conditions/disorders, including ASD. Those research studies only used grandiose-narcissism-based categorical DSM criteria in order to determine co-occurrence rates. This limited approach may underestimate the prevalence of narcissistic spectrum manifestations within individuals with ASD without intellectual disabilities.

Only one study by Strunz et al. (2015) performed a direct comparison between individuals with ASD without intellectual disabilities to those with NPD using a dimensional approach. The researchers assessed levels of narcissism personality traits using the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ). The study revealed that individuals with ASD scored similarly to healthy controls on the Narcissism DAPP-BQ subscale, but lower than individuals with NPD. However, the Narcissism DAPP-BQ subscale does not differentiate between vulnerable and grandiose narcissism, making it difficult to determine the extent to which mixed features of grandiosity and vulnerability contribute to the subscale score.

The relationship between ASD and NPD, considering the dimensions of narcissistic grandiosity and vulnerability, represents an important differential diagnosis and potential ground of comorbidity, since both conditions show high grades of pervasiveness, a life-long course, ego-syntonic traits, and difficulties in building up and sustaining interpersonal relationships (Broglia et al. 2023).

The first research study directly investigating the dimensions of narcissistic vulnerability and grandiosity in a sample of adults diagnosed with ASD without intellectual disabilities was conducted by Broglia et al. (2023). The researchers used the PNI-52 instrument, specifically designed to distinguish between the two main dimensions of NPD. They found that individuals with ASD scored significantly higher than the normative population at the PNI-52 Total Score; in particular, significative differences emerged in the vulnerable narcissism dimension,[1] but not in terms of grandiose narcissism. Finally, Broglia et al. (2023) found that 28.7% of people in their sample could be considered potentially at risk for pathological narcissism.

These findings suggest a higher rate of comorbidity between the two disorders than previously reported. Moreover, the dimension of narcissistic vulnerability could explain, at least partially, the internalising symptoms frequently reported by ASD individuals without intellectual disabilities (Broglia et al. 2023).

The Vulnerable Narcissism subscale may provide indirect support for the hypothesis that ASD individuals exhibit more vulnerable narcissistic traits rather than grandiose ones. Of particular interest is the direct correlation observed, especially in the Social Relatedness subscale. This correlation suggests that challenges in social and interpersonal interactions may be a common area where narcissistic vulnerability and autism phenomenology intersect. It is possible that difficulties in social contact, compounded by avoidant and inhibited interpersonal styles characteristic of vulnerable narcissism, could exacerbate the neuroatypical impairments seen in individuals with ASD (Broglia et al. 2023).

Personality profile

Emerging research suggests a distinct Big Five Factor personality profile[2] in ASD individuals, characterised by elevated levels of neuroticism, particularly in those displaying frequent psychiatric symptoms and lower levels of adaptation (Schwartzman et al. 2016). Additionally, ASD individuals tend to exhibit lower levels of openness, conscientiousness, extraversion, and agreeableness (Lodi-Smith et al. 2019).

Conversely, recent studies in the realm of narcissism have highlighted a connection between vulnerable narcissism, characterised by emotional dysregulation and negative emotions such as shame, guilt, rage, and depression, and the personality trait of neuroticism (Miller et al. 2018; Soleimani et al. 2022). This suggests a potential link between the phenomenology of ASD and vulnerable narcissism through the shared trait of neuroticism, which may underlie both vulnerability to narcissism and certain fragile aspects of personality in individuals with ASD.

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The complexities of diagnosing and differentiating between ASD and NPD highlight the importance of thorough assessments and consideration of various factors in clinical settings. In accordance with the contemporary understanding of narcissism, it is beneficial to explore both the vulnerable and grandiose aspects of narcissism in individuals with ASD to address issues related to differential diagnosis and comorbidities.

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[1] Vulnerable narcissism was significantly associated with the "Ritvo Autism and Asperger Diagnostic Scale - Revised" subscale Social Relatedness.

[2] The Five Factor Model (FFM) of general personality structure comprises five broad domains: neuroticism (oremotional instability vs. stability), extraversion (vs. extraversion), openness (or unconventionality), agreeableness (vs antagonism), and conscientiousness (or constraint vs. disinhibition).

The ICD and DSM personality disorders are viewed as maladaptive variations of the FFM. However, it is important to note that no single measure of the FFM can fully encompass every personality disorder. The dimensional trait models found in the DSM-5 Section III and the ICD-11 are explicitly aligned with the FFM (Widiger & Crego 2019).