There is a significant overlap between adult ADHD and substance use disorder (SUD)1,2

The presence of SUD can make treatment of ADHD more challenging3

Image: Man Looking Out The Window

Adult ADHD and SUD

Image: Man Drinking Alcohol

SUD is prevalent in adults with ADHD, and may relate to the core symptoms of the disorder1,3

  • Risk for SUD has been found to be double for individuals with ADHD vs those without4
  • Approximately 50% of adolescents and adults with SUD also have ADHD (which generally develops first)2,5
  • A recent multicenter survey of adults newly diagnosed with ADHD found that SUD was the most common comorbid disorder, occurring in 39% of patients1

In particular, the rates of tobacco use, alcohol use, and marijuana use are higher2-4

  • Alcohol use has been found to be nearly 10 times more common in adults with ADHD3
  • Adolescents with ADHD are up to 3 times as likely than those without to smoke, and 4 to 5 times more likely to progress to heavy use of nicotine and marijuana after trying these substances once2,3
  • Of the core ADHD symptoms, hyperactivity/impulsivity have shown a more robust relationship with abuse of alcohol and tobacco4

Is there a link between the “ADHD brain” and the “substance use brain”?

Evidence shows that patients with ADHD and SUD share similar abnormalities in brain structure and function, including4:

  • Smaller volumes in the frontal cortex, cerebellum, and subcortical structures4
  • Deficits in anterior cingulate activation4
  • Alterations in dopaminergic and striatal involvement2,4

It has also been postulated that genetically mediated personality traits common to both ADHD and SUD (such as novelty seeking and impulsivity), may result from shared neurologic substrates.5

A psychosocial link has also been suggested between the social difficulties of childhood ADHD and later “self-medication” with substances.2

You can learn more about the neurobiology of adult ADHD here

Managing ADHD Within the Context of SUD

Treating ADHD in adults with underlying SUD presents certain clinical complexities:

  • ADHD can significantly impact the development and course of SUD, making early diagnosis important6
  • Stimulant medications, which constitute the mainstay of pharmacotherapy in adult ADHD, have been shown to decrease the risk for developing SUD, due possibly to their protective effect against impulsive decision making or to the prosocial benefits of treatment7
    • Stimulants, however, increase dopamine levels in the brain—the same mechanism through which illicit substances exert their reward effects8
    • Risk of abuse of stimulants is increased in patients with SUD, particularly young adults6,8

Common Comorbidities in Comorbid Complex ADHD: Prevalence, Age of Onset, Diagnosis, and Clinical Implications

Dr. Cutler, MS, MD, associate clinical professor in the Department of Psychiatry, SUNY Upstate Medical University in Syracuse, NY, discusses comorbid complex ADHD—prevalence, age of onset, diagnosis and clinical implications.

Hello, I'm Dr. Andrew Cutler, associate clinical professor in the Department of Psychiatry, SUNY Upstate Medical University in Syracuse, New York. And I'm pleased to be discussing comorbid complex ADHD – prevalence, age of onset, diagnosis, and clinical implications.

Comorbid complex ADHD is very common — studies show that three- quarters of individuals with ADHD have at least one psychiatric condition, and 80% of those have more than one comorbidity. 1

But why do people with ADHD have comorbidities? It’s possible that one disorder is a precursor to the other (evolving over time), it could be a risk factor for developing the other, or they may have a common genetic basis. Some comorbid disorders (such as depression and anxiety) may develop due to the impact of ADHD, making it a secondary condition. 2,3

The comorbidity profile can change throughout the lifespan. In children and adolescents, studies have shown a high incidence of oppositional defiant disorder, which decreases in adulthood. However, in adults, we see problems with emotional dysregulation, stubbornness, trouble managing anger, and other negative emotions. In addition, those comorbidities that tend to be less common in childhood, such as conduct issues, anxiety, major depressive disorder, and substance use disorder, increase in incidence through adolescence, and into adulthood.

The cumulative burden of comorbid complex ADHD evolves and accumulates throughout the lifespan. For example, although oppositional defiant disorder is the most common comorbidity in children, conduct disorder and anxiety are also seen, with the impact of these, along with ADHD, resulting in low self-esteem in this age group. Moving from childhood into adolescence and adulthood, oppositional defiant disorder and conduct disorder decrease, but criminal behaviors start to show, with antisocial personality disorder becoming more common. In addition, learning delays in childhood develop into complex learning difficulties in adolescence and adulthood. With this progression, people often become demoralized and frustrated, resulting in lack of motivation and under achievement. Substance abuse comes into play as well. 2,4-8Es

The presence of comorbidities in different age groups can complicate the diagnosis of ADHD, as symptoms of these comorbidities often overlap with symptoms of ADHD. For example, ADHD symptoms of restlessness, agitation, difficulty concentrating, and decreased attention are also seen in major depressive disorder, bipolar disorder, anxiety, substance use disorder, and sleep disorders; and the ADHD symptom of impulsivity [activate slide build] is also seen in conduct disorder, bipolar disorder, and substance use disorder. 2,9

So, given the overlap of symptoms of ADHD and its comorbidities, what are the steps to ensure an accurate diagnosis? First, it's important to establish the diagnosis, by confirming that the individual meets DSM-5 criteria for ADHD. Then, you should rule out alternative explanations for the symptoms. Finally, and as we've already talked about, it's important to assess for comorbid conditions, which may affect the treatment of ADHD, as well as the diagnosis. 10

For example, to differentiate ADHD from depression, it is necessary to identify which symptoms of depression overlap with ADHD and which are distinct. Overlapping symptoms include loss of motivation, problems concentrating, and restlessness or irritability. So, if your patient has any of these symptoms, it could be ADHD, depression, or both. However, if your patient has only symptoms of depression that are distinct from ADHD, such as feelings of sadness, thoughts of suicide, or changes in eating or sleeping, it is likely depression. 2

Thank you for being part of this Team ADHD educational presentation.

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