Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by developmentally inappropriate symptoms of inattention, hyperactivity and impulsivity and significant impairment in multiple domains of functioning (American Psychiatric Association [APA], 2000
). Impairment in the school domain is one of the most prominent difficulties faced by children and adolescents with ADHD (DuPaul & Stoner, 2003
). Compared to their peers, children with ADHD earn significantly lower school grades (Frazier et al. 2007
), score significantly lower on standardized achievement tests (Frazier et al. 2007
) and experience higher rates of special education placements, grade retention and school dropout (Barkley, 2006
; Molina et al., 2009
). Given the negative long-term implications of chronic academic underachievement and underperformance on occupational functioning and financial stability, these trends are of major concern (Barkley, Murphy, & Fischer, 2008
; Biederman et al., 2006
Although it is clear that children diagnosed with ADHD commonly experience academic underachievement that persists into adolescence (Fischer, Barkley, Edelbrock, & Smallish, 1990
; Massetti et al. 2008
), less is known about factors that predict these negative academic outcomes. Longitudinal prediction studies are important given the observed variability in the academic outcomes of children diagnosed with ADHD. For example, the prevalence of ADHD in college settings is estimated to be between 2 and 8%, which is not that different from the prevalence in elementary school (DuPaul, Weyandt, O’Dell, and Varejao, 2009
), demonstrating that many adolescents with ADHD perform well enough in secondary school to gain admission to college. It is essential to ascertain the specific, potentially malleable, childhood characteristics that are linked to persistent academic underachievement, as their identification could serve to direct early intervention efforts.
Predictors of academic underachievement have been examined in general population samples and in samples of children diagnosed with ADHD. In general population samples, attention problems during childhood have consistently been shown to predict lower academic achievement during adolescence as measured by standardized tests (Fergusson & Horwood, 1995
; Fergusson, Lynskey & Horwood, 1993
; Fergusson, Lynskey & Horwood, 1997
) and functional outcomes, such as grade retention and school dropout (Galera, Melchior, Chastang, Bouvard, & Fombonne, 2009
). The series of studies by Fergusson and colleagues demonstrated that the academic underachievement of children with ADHD is uniquely explained by attention problems. Specifically, while comorbidities such as conduct problems may contribute to academic underachievement (Galera et al., 2009
), it is clear that there is an independent negative relationship between attention problems in childhood and academic outcomes in adolescence (Fergusson, Lynskey & Horwood, 1997
). The evidence collected to date also supports the assertion that academic underachievement is more strongly related to symptoms of inattention than to symptoms of hyperactivity/impulsivity (Fergusson & Horwood, 1995
Rapport, Scanlan, and Denney (1999)
expanded on the work by Fergusson and colleagues by testing the hypothesis that a Dual Pathway Model exists, whereby classroom performance mediates the relationship between attention problems and academic achievement. In a general population cross-sectional sample, Rapport et al. (1999)
found that teacher-rated classroom performance significantly mediated the relationship between attention problems and academic achievement to the point where the direct relationship was rendered nonsignificant. The overall model, including attention problems, select cognitive abilities and classroom performance, accounted for 77% of the variance in achievement on standardized tests. DuPaul et al. (2004)
later supported this finding by demonstrating in a general population cross-sectional sample, that teacher-rated classroom performance was more closely related to academic achievement than symptoms of ADHD.
Only a few studies have longitudinally examined predictors of academic outcome in samples of children diagnosed with ADHD. Longitudinal studies with diagnosed samples are important to support the predictive validity of an ADHD diagnosis. Further, diagnosed samples are often more severe than general population samples and different predictor variables may be important. In the most comprehensive longitudinal study of academic outcomes completed to date, Massetti et al. (2008)
reported on a cohort of children diagnosed with ADHD at 4–6 years of age and assessed seven times over an 8 year period. A diagnosis of ADHD in childhood predicted lower reading, spelling and math standardized achievement test scores in adolescence after controlling for intelligence. Interestingly, children diagnosed with ADHD – Inattentive Type in childhood had lower scores in adolescence than children diagnosed with ADHD - Combined Type and comparison children. To date, the role of the predictor variables shown to be important in general population samples (e.g. classroom performance) has not been examined in samples of children diagnosed with ADHD. Further, tests of meditational relationships, such as the model presented by Rapport et al. (1999)
, have not been completed in longitudinal samples of any kind.
Across all of the studies reviewed above, academic outcome was most often defined as performance on standardized achievement tests. Standardized test results provide a limited definition of academic outcome, which may or may not reflect overall academic performance in school (Loe & Feldman, 2007
). The educational psychology literature emphasizes that school grades and achievement scores are separate indices of academic outcome and should not be used interchangeably. Grades are strong predictors of school dropout (Keith & Benson, 1992
), are often weighted more heavily than standardized test scores in the college admission process, and are highly correlated with college freshman grade point average (Zwick & Sklar, 2005
). Further, malleable factors such as the child’s motivation and behavior are more strongly related to grades than they are to achievement scores (Barrington & Hendricks, 1989
). Finally, school grades warrant study because of their ecological validity. Grades are the most frequently used metric of learning and are viewed by parents as the primary indicator of academic success (Wentzel, 1989
The primary goals of this study are to: 1) Examine predictors of two different types of academic outcomes (i.e. standardized test performance and grades in school); 2) Expand our understanding of variables that predict academic outcome by examining a wide range of predictor variables, including academic and service use variables; and 3) Determine if the relationship between symptoms of ADHD in childhood and academic outcome in adolescence is mediated by academic and/or service use variables.
We examined three academic predictor variables. Given the findings from the Rapport et al. (1999)
and DuPaul et al. (2004)
studies, we examined the predictive power of teacher-rated classroom performance. We also included parent-ratings of homework completion and homework management as academic predictors because time spent on homework and the amount of homework completed are positively correlated with class grades and achievement test scores (Cooper, Lindsay, Nye, & Greathouse, 1998
; Cooper, Robinson, & Patall, 2006
). For service use, we examined two commonly received services for children with ADHD: 1) psychotropic medications prescribed for ADHD; and 2) special education services. Consistent with previous research (Rapport et al., 1999
), we hypothesized that teacher-rated classroom performance would mediate the relationship between symptoms of ADHD in childhood and academic outcomes in adolescence. Given that previous studies have demonstrated that homework problems are related to achievement scores and grades (Cooper et al., 2006
), we predicted that the homework variables would also mediate the relationship between symptoms of ADHD and academic outcomes in adolescence.