The DSM included in its fourth edition of “Pervasive Developmental Disorders – PDD” autistic disorder, Asperger’s disorder, childhood disintegrative disorder, pervasive developmental disorder not otherwise specified – PDDNOS- , and Rett’s disorder. In its fifth and last version, the manual opted to include Kanner’s autism, Asperger’s and PDD-NE under a single heading, being referred to as “Autism Spectrum Disorder”, a change that contributed to the disappearance of Rett syndrome and childhood disintegrative disorder from the group.
On the other hand, the World Health Organization (WHO) classification also uses the term “Pervasive Developmental Disorders” in its tenth edition, although its list is not identical to that used in the previous DSM. In ICD11, autism spectrum disorders are included under the general heading “Neurodevelopmental Disorders”.
Therefore, in view of these name changes, it is common for the term “autism” to be generally used, both in the media and in professional or associative environments, to refer to all disorders included under the denomination of “Pervasive Developmental Disorders” (ICD10) or the expression “Autism Spectrum Disorders – ASD” (DSM5).
Accumulated experience shows that there is great variability in the expression of these disorders. The clinical picture is not uniform and its presentation ranges on a spectrum from more to less affected; it varies over time and is influenced by factors such as the degree of associated intellectual ability or access to specialized support.
The concept of ASD attempts to reflect the clinical and social reality we face. However, it is not a universally shared term. The term ASD facilitates the understanding of the social reality of these disorders and promotes the establishment of support for affected individuals and their families.
Differential diagnosis of autism
We refer to autism as a set of observable behaviors that may or may not be associated with another known disorder. Therefore, if a person receives a diagnosis of a particular disease, such as Fragility X or Tuberous Sclerosis, and presents symptoms characteristic of autism, he/she will receive both diagnoses.
On the other hand, it is necessary to formally assess the level of development or intellectual, communicative and adaptive capacity of the person since, knowing their levels, it will be possible to evaluate the presence of possible symptoms of autism. When discrepancies are seen between the general mental age and the socio-communicative development and the possible tendency to routine, and qualitative differences appear, characteristic of autism, the double diagnosis of intellectual disability (formerly called mental retardation) and autism (or TDD or ASD) can be established.
The diagnosis of intellectual disability should not be made before the age of five years, using the term Global Developmental Delay. Many authors question the limited validity of making a dual diagnosis if the person does not exceed an IQ of more than 20 points, since the clinical presentation and the real needs of the person will be basically determined by his or her intellectual disability.
It is also necessary to make a differential diagnosis with severe developmental language disorders (dysphasia), in which the symptomatology may initially coincide, since in these disorders there is a marked improvement in social and communication skills.
The importance of clinical diagnosis
There are other disorders with which it is common to confuse MDD, such as multiple and complex developmental disorder, childhood-onset schizoid personality disorder and right hemisphere syndrome.
In any case, clinical diagnosis is fundamental for the advancement of knowledge, but when establishing a personalized support program it is also important to determine the health, educational, cultural and social needs. These are the elements that individualize the person within the varied spectrum of these disorders are those that ultimately determine the individualized plan to be followed.