Note that investigating the biometric decomposition of symptom count correlations is only applicable to the full sample, because the subsample analysis of individuals symptomatic by age 17 was, by definition, a within-individual analysis and disregards unaffected or later-affected (after age-17) co-twins. Resulting biometric decompositions would be difficult to interpret because included in the cross-twin correlations are only those pairs of twins both of whom were symptomatic by age 17.
