Elusive Nature of Schizotypal Personality Disorder: A Case Report on Diagnostic and Treatment Challenges

Abstract

Schizotypal Personality Disorder (SPD) is characterised by pervasive social and interpersonal deficits, cognitive–perceptual distortions, and eccentric behaviour, and is frequently misdiagnosed due to symptom overlap with schizophrenia, anxiety, and obsessive-compulsive symptoms. It occupies a distinct position across diagnostic systems, being placed within schizophrenia spectrum disorders in the International Classification of Diseases, 11th Revision (ICD-11), while the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) classifies it under Cluster A personality disorders. This case describes a 25-yearold male who initially presented with social anxiety and ritualistic behaviours and was diagnosed with social anxiety disorder with obsessive-compulsive features. In subsequent visits, additional diagnoses of depression and psychosis were considered based on the evolving symptom profile. He responded poorly to treatment despite multiple trials of medications and inpatient care. On his fourth admission, a comprehensive evaluation with diagnostic psychometry was undertaken, incorporating birth and developmental history and thorough tracking of the longitudinal course of symptoms, which revealed an enduring pattern of eccentric behaviour, persistent odd beliefs, impaired interpersonal functioning, constricted affect, transient stress-related suspiciousness, and poor treatment adherence, leading to significant occupational and social impairment. The diagnosis was revised to SPD, and he was treated with psychotherapy and pharmacotherapy. The case highlights the importance of a Kraepelinian longitudinal approach to evaluation in psychiatry, which is often neglected in contemporary practice.