Background: Despite increased attention and recognition of autism spectrum
disorders, many patients suffering from these disorders remain undiagnosed or are diagnosed
late due to their subtle clinical presentation. The challenge for clinicians working in the field
of mental health is not in screening and diagnosing young children showing typical signs of
autism spectrum disorders, but rather in identifying patients at the high-functioning end of
the spectrum whose intellectual abilities mask their social deficits.
Objectives: Because therapeutic interventions differ radically once the diagnosis of ASD has
been made, it is important to understand the trajectory of those adolescents and identify clues
that could help raise the diagnosis of ASD earlier.
Method: Records of eight adolescents with a late diagnosis of ASD were retrospectively
reviewed to identify relevant clinical features that were overlooked in childhood and early
Results: The patients were previously misdiagnosed with multiple mental health disorders.
These cases showed striking similarities in terms of developmental history, reasons for
misdiagnosis, and the clinical picture at the time of ASD recognition. The cases were
characterized by complex and fluctuating symptomatology, including depression, anxiety,
behavioural problems, self-injurious behaviour and suicidal thoughts. Their autism spectrum
disorder (ASD) went previously undiagnosed due to the individual’s intelligence and
learning abilities, which masked their social deficits and developmental irregularities. Signs
of ASD were continuously present since childhood in all the eight cases. Once the
developmental histories and the psychiatric evaluation of these adolescents were done by
psychiatrists with appropriate knowledge of autism, the diagnosis of ASD was made.
Conclusion: The ASD hypothesis should be raised in the presence of confusing symptoms
that do not respond to usual treatment and are accompanied by an irregular developmental
background. It is indeed a difficult diagnosis to make; however, the focused clinician can
note subtle signs of ASD despite the intellectual learning of social codes. Family history,
developmental irregularities, rigidity, difficulty in spontaneously understanding emotions,
discomfort in groups and the need to be alone are significant indicators to recognize. Once
the diagnosis has been considered, it must be confirmed or rejected by an experienced
multidisciplinary team. The challenge for clinicians working in the field of mental health is
not in screening and diagnosing young children showing typical signs of ASD, but rather in
identifying patients who are at high-functioning end of the spectrum whose intellectual
abilities mask their social deficits.