IDD (intellectual developmental disorder)

Diagnostic criteria

IDD diagnostic criteria

Intellectual and adaptive functioning deficits in conceptual, social, and practical domains with the following 3 criteria being met:

  • A. Deficits in intellectual functioning
    • Reasoning
    • Problem solving
    • Planning
    • Learning
    • Judgement
  • B. deficits in adaptive functioning that result in failure to meet developmental and social standards for personal independence and social responsibility
    • communication
    • social participation
    • independant living
    • across multiple environments (home, school, community)
  • C. Onset of intellectual and adaptive deficits during the developmental period

Risk factors

  • Adverse postnatal development
    • Deprivation of nurturance and other stimulation
  • Pregnancy and perinatal problems
    • fetal malnutrition, prematurity, hypoxia, viral and other infections. trauma
  • general medical conditions
    • seizure disorders, infections, etc

Comorbidity

• Very common (range 10 – 70%) • Type may vary according to severity of IQ impairment • Depression, anxiety, antisocial more common in those with higher levels • Psychotic, autism spectrum disorder more likely in lower levels • Challenging behaviour common • ?reflects emotional problems • Maltreatment common (cause or outcome?) • Beware diagnostic overshadowing

ASD

Three domains of ASD

  • Social
  • Communication
  • Repetitive and restrictive behaviour

Diagnostic criteria

  • A. Persistent deficits in social communication and social interaction across multiple contexts
    • Social emotional reciprocity
    • nonverbal communicative behaviours
    • relationships
  • B. Restricted repetitive behaviours, interest or activities (at least 2)
  • C. Symptoms must be present in early childhood (however may not fully manifest until social demands exceed limited capacities)
  • D. Clinically significant impairment

Social communication disorder is pragmatic difficulties with communication just without restricted and repetitive behaviour

Risk Factors

• Family history • Rate of autism in siblings aprox 50 times than of general population • High concordance in monozygotic twins • Recurs in families at rate of 3 – 6% • Maternal age • Paternal age • Perinatal complications (e.g., hypoxia)

Common comorbidities

• IDD (50 – 80%) • Specific Learning Disorder • Speech Language Disorders • Anxiety • ADHD • Mood • Tic Disorder • Seizure Disorders