Effects of Symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD) on Academic Performance and Educational Attainment.

The aim of this longitudinal population-based cohort study was to examine the effects of ADHD and ODD symptoms in adolescence on academic performance at age 16, and on educational attainment by the age of 32. The population studied here was the Northern Finland Birth Cohort 1986 (NFBC1986). The participants were classified into four groups: those with symptoms of ADHD, ODD, ADHD + ODD, and a control group. Early academic performance at the age of 16 years was based on the Joint Application Register for Secondary Education, and eventual educational attainment was derived from the registers of Statistics Finland and included information recorded up to 2018. Although symptoms of pure ODD had a negative effect on academic performance at school relative to the control group, this effect was weaker than that of pure ADHD symptoms. The ADHD + ODD group, both males and females, had the greatest deficits of all in educational attainment in adulthood and failed to progress to an institution of higher education as often as the control group. Symptoms of ODD in adolescent females predicted educational attainment in adulthood that extended no further than the compulsory comprehensive school level. The results remained statistically significant after adjustment for the educational level of the parents of the subjects, family type, and any psychiatric disorders (other than ADHD or ODD). The findings provide valuable information on the pervasive effects of co-occurring symptoms of ADHD and ODD that persist into adulthood.