What is ADHD?
ADHD stands for Attention Deficit Hyperactivity Disorder. It is a neurodevelopmental disorder characterized by inattention, hyperactivity and impulsivity that interferes with daily functioning. ADHD symptoms often begin in childhood and can continue into adulthood.
The exact causes of ADHD are unknown but research suggests genetics and environmental factors both play a role. ADHD is one of the most commonly diagnosed mental disorders in children. An estimated 9.4% of children in the U.S. have been diagnosed with ADHD as of 2016.
Is ADHD something you’re born with?
There is strong evidence that genetics play a major role in ADHD:
- ADHD tends to run in families – if one family member has ADHD, there is an increased chance that other family members will too.
- Studies of twins show that ADHD has a high heritability, meaning a large amount of variation in ADHD symptoms can be explained by genetics.
- Research has identified differences in certain genes, as well as brain structure and function in people with ADHD compared to those without.
However, ADHD is considered a complex polygenic disorder. This means that multiple genes are involved, each contributing only a small amount to the overall risk. Environmental factors also play an important role.
So while genetics are a major risk factor, it’s not as simple as being “born” with or without ADHD. The latest research suggests that both nature and nurture work together in the development of ADHD.
Can you develop ADHD later in life?
ADHD has traditionally been considered a childhood disorder, with symptoms expected to emerge before age 12. However, the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) states that in a minority of cases, onset of symptoms may not become apparent until adolescence or adulthood.
Several long-term studies provide evidence that ADHD can newly develop or be diagnosed in adulthood:
- In a 33-year longitudinal study, 68% of children with ADHD continued to meet criteria for ADHD as adults. However 32% did not, suggesting their symptoms remitted by adulthood.
- A 10-year study found that 2.7% of adults ages 19-40 who did not meet criteria for ADHD as children went on to develop sufficient symptoms later in life to warrant an ADHD diagnosis.
- In a 5-year study of adults ages 21-40 who did not have childhood ADHD, 4.4% met criteria for adult ADHD during follow-up assessments.
Additionally, many individuals with ADHD are not diagnosed until later in life. This may be because:
- Their symptoms were not impairing enough in childhood to be identified.
- They were able to compensate for their symptoms when younger.
- Expectations and demands increase with adulthood, revealing previously hidden symptoms.
- A traumatic brain injury or other factors alter the brain in ways that unmask latent ADHD symptoms.
In summary, while ADHD often originates in childhood from a combination of genetic and environmental influences, it is possible in some cases for ADHD symptoms to newly emerge or become impairing enough for diagnosis later in adolescence or adulthood.
Why might symptoms appear later in life?
There are several factors that could lead to ADHD symptoms newly emerging or worsening in adolescence or adulthood:
- Brain development – The prefrontal cortex, responsible for executive functions like focus, planning and impulse control, continues to develop into the 20s. Delayed development here may unmask ADHD symptoms.
- Increasing demands – As teens transition to college or adults take on greater work/family responsibilities, previously manageable ADHD symptoms may become impairing.
- Loss of structure – Many teens and adults with undiagnosed ADHD rely heavily on external structure from parents or school. Removing this structure can reveal symptoms.
- Substance use – Adolescent substance use may trigger the onset of ADHD symptoms and impairment in genetically susceptible individuals.
- Brain injury – A traumatic brain injury can alter the brain in ways that bring about ADHD symptoms, like inattention and impulsivity.
- Medical conditions – Certain medical problems that develop with age like sleep apnea, hormone imbalances, strokes, etc. may result in ADHD-like symptoms.
In cases where ADHD symptoms only become impairing later in life, individuals likely had an underlying genetic susceptibility to ADHD. But various biological, environmental and lifestyle factors may have interacted to keep symptoms below a diagnosable threshold earlier on.
Can adults be diagnosed with ADHD for the first time?
According to DSM-5 criteria, a diagnosis of ADHD requires the presence of impairing symptoms before age 12. However, adults can still be clinically diagnosed with ADHD for the first time if:
- They had significant symptoms in childhood that were missed or not recognized as ADHD at the time.
- They have late-onset ADHD where their first symptoms emerged after age 12.
- A doctor determines their symptoms and impairment are better accounted for by ADHD than another condition.
The diagnostic process in adults may involve:
- Interviews about current symptoms, childhood history and family members’ recollections.
- Rating scales assessing past and present ADHD symptoms.
- Neuropsychological testing to evaluate attention, impulse control and executive functioning.
- Determining symptoms are not better explained by another disorder like anxiety, depression or a medical condition.
- Looking for evidence of impairment in multiple life domains like work, relationships, education, etc.
While uncommon, it is possible for ADHD to be newly diagnosed in adulthood. But a thorough evaluation is needed to confirm symptoms have been present since childhood or determine late adolescent/adult onset.
Conclusion
In summary:
- ADHD is a neurodevelopmental disorder with strong genetic factors but also influenced by environment.
- Although ADHD often originates in childhood, in some cases symptoms may not become apparent or impairing until adolescence or adulthood.
- Multiple factors can contribute to late onset of ADHD symptoms and impairment.
- Adults can be clinically diagnosed with ADHD for the first time, but a thorough evaluation is required.
While ADHD is usually considered a childhood disorder, emerging research indicates it is possible to develop symptoms later in life in susceptible individuals due to both biological and environmental influences. But experts agree more research is needed on adults with ADHD without a childhood diagnosis.