The language used to describe neurodevelopmental conditions like autism has changed significantly over time, reflecting a growing scientific understanding. Historically, the classification of mental health conditions lacked the specificity and structure professionals rely on today. The 1980s marked a major turning point with the publication of the third edition of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-III). This new manual established a more empirical, criterion-based approach to diagnosis, giving many conditions their own distinct identity.
The Dominant Diagnostic Framework (1980-1987)
The specific term used in the DSM-III, published in 1980, for the condition now commonly known as autism was Infantile Autism. This label emphasized the original observations of the condition, focusing on characteristics seen in very young children. The diagnosis was housed within a larger, newly created class of conditions called Pervasive Developmental Disorders (PDD).
The term “infantile” highlighted the strict age-of-onset requirement, demanding that symptoms must have begun before 30 months of age for a diagnosis to be made. This criterion ensured a narrow definition, distinguishing it from conditions that manifested similar symptoms later in childhood. This approach resulted in a highly restrictive diagnostic category that captured only the most severe, classic presentations.
The Pervasive Developmental Disorders category acknowledged that these conditions involved widespread developmental delays, not merely delays in one area like language. The initial DSM-III PDD category included Infantile Autism and a less common diagnosis called Childhood Onset Pervasive Developmental Disorder. This structure reflected a recognition that autism shared some underlying developmental features with other conditions.
Defining Features and Criteria (DSM-III)
The DSM-III established six specific criteria that had to be met to receive the diagnosis of Infantile Autism. The first defining feature was a pervasive lack of responsiveness to other people, meaning the child exhibited a profound failure to engage in reciprocal social interaction.
A mandatory criterion detailed gross deficits in language development, which could manifest as complete mutism or peculiar speech patterns. These patterns often included immediate or delayed echolalia (repeating words or phrases) or pronominal reversal (referring to themselves as “you”). The manual required evidence of these significant communication impairments.
The third required feature involved bizarre responses to the environment, including a strong insistence on sameness and intense resistance to change. This also encompassed peculiar interests in, or attachments to, inanimate objects. The criteria explicitly excluded features of schizophrenia, such as delusions or hallucinations, establishing Infantile Autism as a separate developmental disorder. Because of these strict requirements, a relatively small number of individuals qualified for the diagnosis compared to modern diagnostic rates.
Expanding the Spectrum (The PDD Category)
The restrictive criteria of the 1980 DSM-III proved difficult to apply to all children who displayed clear, but less severe, autistic behaviors. This recognition led to a significant revision in 1987 with the publication of the DSM-III-R, which renamed the primary diagnosis to Autistic Disorder. This change in terminology moved away from the assumption that the condition only presented in infancy, adopting a more developmentally flexible approach.
The DSM-III-R also broadened the diagnostic concept by introducing Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). This new category served as a catch-all for individuals who displayed severe impairments in social interaction and communication, along with repetitive behaviors, but did not meet the full criteria for Autistic Disorder. The introduction of PDD-NOS was a major step toward a spectrum concept, acknowledging a wider range of severity and symptom profiles.
The shift from DSM-III to DSM-III-R resulted in a substantial increase in the number of individuals receiving an autism-related diagnosis. By loosening the criteria, such as dropping the mandatory onset before 30 months, the DSM-III-R effectively broadened the definition. This allowed the inclusion of children who were socially impaired but not necessarily pervasively unresponsive to others.
Bridging the Past and Present Diagnosis
The Pervasive Developmental Disorders category, including Autistic Disorder and PDD-NOS, remained the standard classification throughout the 1990s and 2000s. This historical framework was eventually unified in 2013 with the publication of the DSM-5. The DSM-5 consolidated all previous PDD subtypes, which had grown to include Asperger’s Disorder, into a single, comprehensive diagnosis.
The current term used by clinicians and researchers is Autism Spectrum Disorder (ASD). This modern classification reflects the scientific consensus that the condition is a single spectrum with varying degrees of severity and presentation. The ASD diagnosis in the DSM-5 now encompasses the once-restrictive category of Infantile Autism and broader concepts like PDD-NOS under one umbrella. This evolution reflects the commitment to refine diagnostic tools to accurately reflect the complex reality of neurodevelopmental differences.