Differential Diagnosis: Autism Spectrum Disorder versus Schizotypal Personality Disorder in Geriatric Patients

Vol 10 #10

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Noam Raiter, BA¹, Ana Hategan MD²

 

Author information

1  Medical Student, Michael G. DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.  [email protected]

2  Clinical Professor, Geriatric Psychiatrist, Division of Geriatric Psychiatry, Department of Psychiatry and Behavioural Neurosciences, Michael G. DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.  [email protected]

 

ABSTRACT

The diagnoses of autism spectrum disorder and schizotypal personality disorder were only formally added to the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III) in 1980. This has led to underdiagnosis in older adults many decades after onset. These diagnoses are vastly overlapping and, therefore, differentiation is increasingly difficult in older age. The current case report described an older adult patient presenting with certain abnormal mannerisms involving his eye contact, conversational structure, and specific content fixations.  Although a formal diagnosis has not yet been established, some key points of distinction between autism spectrum disorder and schizotypal personality disorder are presented. Future work is needed to outline the geriatric presentation in individuals with autism spectrum disorder and schizotypal personality disorder.

Introduction

Over the past several decades, there have been significant reforms in the classification and diagnostic accuracy of psychiatric illnesses. Specifically, the now well-known diagnoses of autism spectrum disorder and schizotypal personality disorder were only formally included in the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III) in 1980 (American Psychiatric Association, 1980).  This has led to a distinctive problem of underdiagnosis in geriatric populations and revelation of certain psychiatric disorders many decades after onset. This problem is further complicated as such diagnoses are significantly overlapping and differentiation is increasingly difficult in older age (Barneveld et al., 2011). The current report discusses such a case study and may guide future practitioners encountering similarly unique presentations.

Case report

Mr. H was a 76-year old male who was hospitalized following repercussions of an ischemic stroke and related physical deterioration. When he was seen by the consultation-liaison psychiatry team, he presented as an evidently joyful and optimistic man but had certain mannerisms straying outside societal norms. In conversation, he failed to make appropriate eye contact and to follow traditional conversational flow. However, his odd speech patterns were halted when reaching a topic of particular interest. A particular fascination was with measurements of his household (i.e., height of stairs, size of the bedrooms) and his love for horses. He would speak circumstantially on these topics. Further, he later stated that he “likes spending time with horses because they do not judge me and talk back like people do”. Additionally, he showed remarkable recall of long-term memory stating details about his childhood such as all the house addresses that he has ever lived in.

Upon obtaining collateral information from his sister, it became apparent that some of these characteristics have been present since his childhood. He was described as always seen as “odd” growing up and acted more “childlike than appropriate.” He had many acquaintances but few close friends. His academic success was never a concern and was actually regarded to have a remarkably detailed memory. His thinking pattern was more circumstantial and specific interests such as taking care of horses were picked up. Increasing agitation was noted when his thought process was interrupted or when his routine was disrupted. He has preferred to spend most of his time alone despite stating he did enjoy the company of people. He has never been diagnosed with a psychiatric disorder and his mood has been normal.

Discussion

Mr. H presented a unique case not well discussed in existing literature. Although a formal diagnosis has not yet been established, some key points of distinction between autism spectrum disorder and schizotypal personality disorder are presented in Table 1.

Future work should aim to outline the developmental changes seen in individuals with both autism spectrum disorder and schizotypal personality disorder in order to better understand progression with age and geriatric presentation. Furthermore, the reality of aging patients with these disorders is that they may require a high level of support, at least due to problems with social communication and interpersonal interaction, while they may face a high risk of underdiagnosis or misdiagnosis (Hategan et al., 2017).

Table 1. Similarities and differences between autism spectrum disorders and schizotypal personality disorders

	Autism spectrum disorder	Schizotypal personality disorder
Social interactions	Deficits in social reciprocity   Deficits in developing/maintaining social relationships	Fear of social closeness (due to fear of “psychological annihilation”) (Waska, 2003) Deficits in developing/maintaining close/intimate social relationships
Communication	Stereotyped and repetitive speech Deficits in non-verbal communication (eye contact, facial expressions and conversational norms)	Odd speech (vague, metaphoric, circumstantial)
Affect	Limited/flat affect Lack of empathy	Limited/flat or inappropriate affect
Thought content	Highly specific and fixated interests Rigid routines	Unusual interests Magical and referential thinking Paranoia/suspiciousness
Cognitive abilities	Significant cognitive impairment in some individuals. Savant syndrome may allow for exceptional capabilities in some aspects.	Moderate cognitive impairment (specifically in memory) seen in some individuals
Onset	Symptoms present early in developmental period (intensity may increase with age as social demands exceed capacity)	No explicit onset markers

(American Psychiatric Association, 2013)

 

Conflict of interest

None.

Acknowledgments

None.

 

REFERENCES

American Psychiatric Association. (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). Washington, DC: American Psychiatric Association

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.978089042559

Barneveld, P.S., Pieterse, J., De Sonneville, L., Van Rijn, S., Lahuis, B., Van Engeland, H., & Swaab, H. (2011). Overlap of autistic and schizotypal traits in adolescents with autism spectrum disorders. Schizophrenia Research, 126(1-3), 231-236. doi:10.1016/j.schres.2010.09.004

Hategan, A., Bourgeois, J.A., & Goldberg, J. (2017). Aging with autism spectrum disorder: An emerging public health problem. International Psychogeriatrics, 29(4), 695-697. doi:10.1017/S1041610216001599

Waska, R. (2003). Fragmented attachments: The paranoid-schizoid experience of loss and persecution. Bull Menninger Clin, 67(1), 50-64. doi: 10.1521/bumc.67.1.50.23452