These fast facts highlight key issues related to the occurrence of developmental problems for maltreated children younger than the age of 3:
- Twenty-two percent to eighty percent demonstrate acute and chronic health problems (Chernoff, Combs-Orme, Risley-Curtiss, & Heisler, 1994; Frame, 2002; Hochstadt, Jaudes, Zimo, & Schachter, 1987; Leslie et al., 2005; Silver et al, 1999; Sullivan & Knutson, 2000).
- Eleven percent demonstrate failure to thrive (FTT; National Survey of Child and Adolescent Well-Being, CPS Sample Component Wave 1 Data Analysis Report April, 2005).
- Twenty percent demonstrate growth delays (Silver et al., 1999).
- Four percent to forty-seven percent demonstrate gross and fine motor delays (Leslie et al., 2005; Reams, 1999; Silver et al., 1999).
Differences in rates are most likely caused by variations in methods used to document developmental delays. Information from numerous studies offers evidence that medical problems and growth delays may be not only outcomes of but also risk factors for maltreatment. In particular, physical injuries (both minor and serious), low birth weight, growth delays, and abnormalities in brain functioning are hypothesized outcomes of abuse and neglect (Beniot, 1993; Block, Kreb, American Academy of Pediatrics Committee on Child Abuse and Neglect, & American Academy of Pediatrics Committee on Nutrition, 2005; Crittenden, 1987; Zelenko, Lock, Kraemer, & Steiner, 2000). However, research indicates that children with medical problems and motor delays are at increased risk of being maltreated primarily neglected (Famularo, Fenton, & Kinscherff, 1992; Miller, Fox, & Garcia-Beckwith, 1999; Sullivan & Knutson, 1998, 2000; Wu et al., 2004).
Recent research on the brain structure and brain functioning of maltreated infants may be able to explain how all these physical, social, and emotional problems are interrelated. Research using brain imaging data revealed that children who were maltreated during infancy and early childhood had noticeable differences in overall brain size; the same study found that the duration of maltreatment was associated with greater differences in brain structure (De Bellis et al., 1999). These differences in size and structure of the brain may affect the body's ability to grow, plan, and regulate stress. In other studies of the brain, children exposed to neglect and sexual abuse variously have demonstrated variations in cortisol levels, which affect reactions to stress (King, Mandansky, King, Fletcher, & Brewer, 2001; for a review, see Gunnar & Donzella, 2002).
Neuroscientists currently studying brain development and functioning are working to better understand the pathways by which stress and abuse impact overall brain structure and functioning.