Child Psychiatry Consult

ADHD in the long term


Parents whose kids are diagnosed with ADHD face important questions about what to expect in the long term and how that might inform treatment. Studies find that ADHD diagnosed in childhood tends to persist in up to 65% of adolescents (some estimates are lower depending on criteria used),1 and about 50% of people are estimated to continue to meet criteria for ADHD as adults.2 Many studies have attempted to understand what long-term risks are associated with ADHD, as well as the factors that help better predict which characteristics in childhood might predict those risks. A recent article was published on a cohort of boys followed over 33 years.3 This, as well as other large prospective studies, such as the Multimodal Treatment of ADHD (MTA) provide us with helpful long-range data that inform this article.4-6 This article reviews risks in adolescence and adulthood and the factors thought to be associated with them.

A doctor talking to her patient. javi_indy/ Thinkstock

What predicts persistence of ADHD symptoms in adolescence?

Several factors emerge consistently, including higher symptom severity, comorbid conduct disorder, and lower childhood IQ; other findings include family-related factors, such as lower parental mental health, less-positive parenting, and lower rates of parental education. In general, hyperactivity and impulsivity wanes, while inattention symptoms remain more stable.

What does ADHD predict for adolescents?

Adolescents with ADHD are more than twice as likely to be involved in pregnancies under the age of 18 years, true for both male and female genders.7 This finding also is associated with increased substance use and low academic achievement but not completely explained by it. Adolescents with persistent ADHD symptoms experience poorer educational success than do kids without ADHD symptoms, according to teacher reports of performance and measurements of grade point average. They are more likely to repeat a grade.8 Related but independent is the relationship of substance use disorders in kids with ADHD. Adolescents with ADHD are more likely to use nicotine or marijuana or meet criteria for any substance use disorder than adolescents without ADHD. Finally, adolescents aged 12-18 years with ADHD are at higher risk for motor vehicle accidents and all types of accidental injuries.9

What predicts persistence of ADHD symptoms in adulthood?

A follow-up study of the MTA trial 16 years later looked at ADHD diagnosed before age 12 years and the association with symptom persistence in adulthood, defined by the DSM-5 cutoff criteria of five symptoms. The following factors related to symptom persistence: childhood psychiatric comorbidity, higher ADHD symptom severity, and parental mental health problems. Notably, family socioeconomic status, child IQ, and parental education were not associated. In addition to looking at symptom persistence, other studies have looked at predictors of functional impairment in adulthood following a childhood ADHD diagnosis (independent of whether people continue to meet criteria for the disorder). The main findings that seem consistently related to all functional outcomes, including social, occupational, and educational, are lower childhood IQ and history of conduct problems (in the absence of meeting criteria for full childhood conduct disorder). Educational family-related factors, such as socioeconomic status and lower parental education, were related to lower educational functioning only.

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