“…Low-level parental occupation (Campbell, 1995;Kalff et al, 2001a), family size (Williams et al, 1990), race (Costello et al, 1996), family structure (Velez et al, 1989), low maternal age at delivery (Orlebeke et al, 1998), and maternal depression (Lavigne et al, 1998) are important family-related risk factors. Although the environment in which a child grows up is a potential risk factor for behavioral problems (Kalff et al, 2001b), little is known about its influence on DSM-based diagnoses (Hermanns and Leu, 1998). Data were collected during a longitudinal population study in the south of the Netherlands, titled the Study of Attention Disorders in Maastricht (SAM), that used a two-stage design (Kalff et al, 2001a;Kroes et al, 2001).…”