Table 1.

Neurodevelopmental/psychiatric disorder (NPD)^a cases (N=4,301) within the population-based birth cohort (N=31,220)

NPD hierarchical profilesc		NPD Clustersb
		ASDd	ChildhoodPsychosise	Develop-mental/Cognitivef	Speech/Languageg	Non-Psychosis/Childhood Psychiatrich		Neurologic/Motori
N=4,301						Other: - anxiety - oppositional/conduct - self-injurious	ADHD
ASDd N= 242
Childhood Psychosise N= 41
Developmental/Cognitivef N=1,863
Speech/Languageg N=905
Non-Psychosis/Childhood Psychiatrich	Other N=1,018
	ADHD N=232

^aSelective and relevant group of NPDs among whom all potential autism spectrum disorder (PASD) cases are identified. (See Figure 1).

^bThe NPD clusters were defined from clinical diagnoses from the medical record and the corresponding educational disability classification (EDC) codes from the school records. These clusters were determined by consensus among members of research team (psychologist, two developmental pediatricians, speech/language pathologist, MD epidemiologist).

^cIndividuals in each row have a diagnosis and/or EDC code in the NPD cluster with the solid black box with or without one or more of comorbid NPD clusters presented by gray boxes in corresponding row. Individuals with only Neuro/Motor clusters were not included as NPD cases. Rows were organized according to highest priority (i.e., significance) in identification of PASD.

^dASD Cluster consisted of the EDC code for ASD along with ASD related diagnoses, for example: Autistic Disorder, Early Infantile Autism, Infantile Autism, PDDNOS, Autism Spectrum Disorders, Asperger’s Syndrome.

^eChildhood Psychosis Cluster included diagnoses such as childhood schizophrenia, childhood psychosis, and disintegrative psychosis.

^fDevelopmental/Cognitive Cluster included the EDC codes for developmental cognitive disabilities and developmental delay and diagnoses such as mental retardation/intellectual disability, borderline mental retardation/borderline intelligence, and delayed development.

^gSpeech/Language Cluster consisted of the EDC code for speech/language impaired and diagnoses such as autistic speech, telegraphic speech, echolalia, and mixed receptive-expressive language disorder.

^hNon-Psychosis Childhood Psychiatric Cluster consisted of the EDC code for emotional/behavioral disorder and diagnoses such as attention-deficit hyperactivity disorder, hyperkinetic conduct disorder of childhood, obsessive-compulsive disorder, unspecified disturbance of conduct, oppositional disorder of childhood, self-injurious behavior, and anxiety disorders.

ⁱNeurologic/Motor Cluster included the EDC code for physically impaired and traumatic brain injury disabled and diagnoses such as epilepsy, seizure disorder.