features for a diagnosis (Mattson, et al., 1997). One study indicated that children with FAS have mean IQ scores significantly lower than those with partial FAS and ARND, who do not differ significantly from one another (Chasnoff, Wells, Telford, Schmidt, & Messer, 2010), and another reported a significant relation between general cognitive function and degree of dysmorphic features and growth deficiency (Ervalahti et al., 2007). The average IQ estimate of individuals with heavy prenatal alcohol exposure is 70 for those with FAS (Streissguth et al., 1991) and 80 for nondysmorphic individuals (Mattson, et al., 1997). Although a clinically significant difference between verbal and nonverbal intelligence scores is often present, the direction of this difference is not consistent (for review, see Mattson & Riley, 1998). Furthermore, IQ score is significantly correlated with psychopathology; children with moderate and severe intellectual disability experienced greater psychiatric disturbance, and IQ scores below 50 indicated poor psychiatric outcome (Steinhausen, Willms, & Spohr, 1994).
