Severe teen ADHD symptoms predict lower income and higher arrest rates by age 40

A longitudinal study in Christchurch, New Zealand found that individuals who displayed the most severe ADHD symptoms as adolescents were at an elevated risk of developing substance use disorder, depression, and suicidal ideation in early adulthood. They were also more likely to engage in crime and be unemployed. These individuals tended to have lower income and living standards, and less stable relationships. The paper was published in the British Journal of Psychiatry.

Attention-deficit/hyperactivity disorder, or ADHD, is a neurodevelopmental condition characterized by persistent patterns of inattention, hyperactivity, and/or impulsivity that interfere with daily functioning or development. It typically begins in childhood, although many individuals continue to experience symptoms into adolescence and adulthood. Most often, ADHD is diagnosed when an individual starts school as behavior caused by ADHD comes into conflict with school rules.

ADHD is more commonly diagnosed in males, although females are often underdiagnosed due to less overt symptoms. Genetic factors play a major role in ADHD. ADHD often co-occurs with other conditions such as learning disorders, anxiety, depression, or oppositional behavior. Symptoms can significantly adversely affect academic performance, work productivity, and social relationships.

Study author James A. Foulds and his colleagues used data from a 40-year longitudinal study of a birth cohort in Christchurch, New Zealand to estimate the association between ADHD symptoms in adolescence and a broad range of mental health and psychosocial outcomes in early adulthood up to 40 years of age.

Data used in this analysis came from the Christchurch Health and Development Study. This study enrolled 1,265 individuals born in Christchurch in 1977 and assessed them annually from birth to 16 years of age. After that, data were collected when participants were 18, 21, 25, 30, 35, and 40 years of age. In the final three data collection waves, 75–80% of surviving study participants provided their data.

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Data used in this analysis were assessments of ADHD symptoms, conduct disorder, and oppositional defiant disorder symptoms when participants were 14–16 years of age. Of the data collected between 16 and 40 years of participants’ age, study authors used information on substance use disorders (alcohol and cannabis), illicit drug use, and internalizing mental health problems.

Internalizing mental health problems are psychological difficulties characterized by inwardly directed distress, such as anxiety, depression, and withdrawal. Of the data collected between participants’ 25 and 40 years of age, this analysis used information on participants’ unemployment (lasting at least 3 months), relationship breakdowns, income, and home ownership.

Results showed that the 25% of participants with the most severe ADHD symptoms in adolescence were more likely to smoke tobacco (34% vs 15%), fulfill criteria for alcohol use disorder (26% vs 14%), and cannabis use disorder (18% vs 7%) compared to participants with less severe or no ADHD symptoms.

These individuals also more often met the criteria for major depression (29% vs 19%), anxiety disorders, and suicidal ideation. They were more likely to have been arrested (9% vs 3%), more likely to have engaged in both violent and property crime, and were more often unemployed. Participants who had the most severe ADHD symptoms as adolescents owned their homes less often and tended to have lower personal income. They more often reported breakdowns of relationships.

“Higher levels of adolescent ADHD symptoms are associated with substance use problems and criminal offending in adulthood. Long-term secondary prevention activities are needed to detect and manage coexisting problems among adults with a history of ADHD,” the study authors concluded.

The study sheds light on the links between ADHD symptoms in adolescence and key life outcomes in adulthood. However, it should be noted that the study was conducted on a group of individuals born in a single city (Christchurch) in the same year (1977), meaning that the observed associations may be affected by cultural and social specificities of Christchurch during the studied period. Results in other cultures and other historical periods may differ.

The study authors also note that only 5 participants were prescribed stimulant medication for their ADHD. This differs from the modern situation where people suffering from ADHD receive medication for their condition much more often. Finally, it remains unknown how much the association with the outcomes is due to ADHD symptoms and not due to other co-occurring conditions like autism spectrum disorder, a condition that was largely not diagnosed properly in the 1970s.

The paper, “Long-term outcomes associated with adolescent ADHD symptomatology: birth cohort study,” was authored by James A. Foulds, Joseph M. Boden, Jessica A. Kerr, Katie M. Douglas, Michaela Pettie, Jesse T. Young, Mairin R. Taylor, Katherine Donovan, and Richard Porter.