Final answer:
The concept highlighted is societal construction of mental illness, which refers to how society constructs and defines a mental illness and its symptoms.
Step-by-step explanation:
The sociological concept highlighted by the fact that ADHD was not recognized by the American Psychiatric Association in the form we now know it until 1987 despite children exhibiting the same symptoms of ADHD before 1987 is societal construction of mental illness.
This concept refers to how society constructs and defines what is considered as a mental illness, including the criteria for diagnosis and the understanding of its symptoms. The recognition and acceptance of ADHD as a mental disorder in 1987 by the American Psychiatric Association demonstrates how societal perspectives and knowledge can shape the understanding and recognition of mental illnesses.