1. Exploding Autism Communication impairments Social impairments Restricted/ Repetitive Behaviours & Interests Restricted/ Repetitive Behaviours & Interests Twin studies suggest: - 3 traits correlate 0.3-0.5 - genes only partly overlap - isolated deficits common Monolith or Composite? Happé, Ronald & Plomin, 2006 Nature Reviews Neuroscience

2. Autism: No single neurocognitive explanation Communication impairments Social impairments Restricted/ Repetitive Behaviours & Interests Restricted/ Repetitive Behaviours & Interests Problems recognising mental states Problems generating, planning, monitoring Theory of mind Executive functions Detail-focused cognitive style weak coherence Anxiety (Hallett et al, 2009) Savant skills ( Vital et al, 2009)

3. Implications of fractionated triad 0.6% Abandon search for G/E predisposing to autism Look for contributors to parts of triad No single factor (genetic, neural, cognitive) specific to ASD Overlap with other diagnoses predicted Heterogeneity expected at every level Single deficits common (10% TEDS); dx, needs?