ADHD vs Anxiety
ADHD and Anxiety
ADHD and anxiety share a complicated relationship. There is a robust link between anxiety and ADHD. Estimates vary, but it is estimated up to 50% of people with ADHD will experience anxiety at some point in their life (Katzman et al., 2017). The risk for nearly all anxiety disorders is higher among ADHDers (Katzman et al., 2017). They also share similar symptoms, which can cause diagnostic confusion, particularly when both are present.
ADHD-inattentive type appears to have higher rates of co-occurring anxiety, which can make for a particularly complex clinical picture. Co-occurring ADHD-inattentive type and anxiety are likely the most difficult to tease out diagnostically. Without the presence of hyperactivity, it can be particularly difficult to tease out whether inattention is due to anxiety and worry or due to difficulty regulating attention due to AD(H)D.
Another challenge is that ADHD often comes with secondary anxiety (anxiety associated with ADHD difficulties), different from generalized anxiety disorder. Secondary ADHD anxiety involves being anxious about executive functioning difficulty (anxiety about school and work, missing details, timelines, the stress that comes with difficulty managing time and tasks, and so forth).
ADHD worry is often connected to executive functioning tasks (finances, health, relationships, school, and work), while generalized anxiety will be more global and pervasive in nature. People with generalized anxiety will experience uncontrollable worry for most days; the worry will be disproportionate to the actual stressor.
So, let's dive into the co-occurrence, overlapping traits, and how to distinguish the two. But first, an overview of both (feel free to skip the next two sections if you don’t need the overview):
Contents:
ADHD Overview
ADHD is classified as a neurodevelopment disorder, meaning the onset occurs during the developmental period (typically early childhood) and has a strong genetic component. The parts of the brain that regulate emotions, attention, and focus are impacted in the context of ADHD. ADHD is characterized by persistent inattention, hyperactivity, and impulsivity (American Psychiatric Association 2015). There are three classifications of ADHD a person can be diagnosed with: ADHD-primarily inattentive type, ADHD-primarily hyperactive-impulsive, or combined type.
The Criteria for diagnosing ADHD include the presence of inattention, impulsivity, and hyperactivity (or just inattention in the case of ADHD-inattentive type). The symptoms must interfere with daily functioning in at least two contexts (for example, home and school or work and home) (American Psychiatric Association, 2000). Some common symptoms of ADHD include:
difficulty focusing or staying on task
problems keeping track of materials
trouble following through on complex projects
distractibility and forgetfulness
appearing not to listen when spoken to
increased need to be up and moving
fidgetiness
impulsivity
tendency to interrupt other people
excessive talking
While present from birth, the symptoms of ADHD may not become apparent until demands exceed capacity. And many children develop sophisticated compensatory strategies to offset areas of struggle. In these cases, the person's ADHD is recognized even later in life.
ADHD has a worldwide prevalence of 5.2 % among children and adolescents (Polanczyk et al. 2007). Based on the (CDC), current estimates estimate that 6.1 children in the U.S. are diagnosed with ADHD, approximately 9.4% of children, making ADHD one of the most commonly diagnosed developmental disorders in the U.S.
Overview of Generalized Anxiety Disorder (GAD)
Generalized anxiety is characterized by pervasive, excessive, and uncontrollable worry. The anxiety and worry must be excessive, occurring more days than not for at least six months, about several events or activities (such as work or school performance). The intensity, duration, or frequency of the anxiety and worry is out of proportion to the actual likelihood or impact of the anticipated event. What distinguishes GAD from everyday anxiety and worry is the excessive nature and interference with work, school, and daily living. When a person is experiencing GAD they are often having significant difficulty with completing life's daily activities and responsibilities, leading to problems with school, work, relationships, and more (American Psychiatric Association, 2013).
In addition to difficulty controlling worrisome thoughts, the person experiences three of the following symptoms associated with their anxiety:
1. Restlessness or feeling keyed up or on edge.
2. Being easily fatigued.
3. Difficulty concentrating or mind going blank.
4. Irritability.
5. Muscle tension.
6. Sleep disturbance (difficulty falling or staying asleep, or restless, unsatisfying
To meet the diagnostic criteria for GAD the anxiety must not be due to substances, another medication condition, or better explained by another mental health condition (American Psychological Associates, 2013).
Many people who experience anxiety symptoms do not seek help, and thus it may go undiagnosed at high rates. Approximately 20% of people who experience anxiety seek help. The lifetime risk of a generalized anxiety disorder is 9% (American Psychiatric Association, 2013). The risk of GAD peaks in middle age and declines during the later years of a person's life. In 12 months, the prevalence of GAD among adolescents is 0.9% and 2.9% among adults.
Co-Occurrence of Anxiety and ADHD
ADHD and anxiety are distinct conditions but often co-occur. While estimates vary, approximately half of people with ADHD also have anxiety (Katzman et al., 2017). The right treatment will help improve both symptoms of ADHD and anxiety.
Prevalence Rates of Co-Occurrence
25-50% of ADHD has a co-occurring anxiety disorder (Schatz and Rostain, 2006; Katzman et al., 2017)
Tsang, et al. 2015 found 31% of people with ADHD also met the criteria for GAD.
While 5-15% of children have an anxiety disorder, among ADHD children, the rate of anxiety disorder goes up to 15-35%
Some studies place co-occurrence of anxiety with ADHD as high as 50% (Mancini et al., 1999; Katzman et al., 2017)
ADHD children had higher rates of agoraphobia, simple phobias, separation anxiety disorders, social phobia, and OCD (Spencer et al., 1999).
27% of ADHD children had more than one anxiety disorder (compared to 5% of the control group) Spencer et al., 1999
When anxiety is also present, this can cause ADHD symptoms to be exacerbated. A person who is experiencing ADHD and anxiety may experience exacerbated symptoms of:
Worry
Feeling on edge
Stress
Fatigue
Sleep issues
Greater impairment to working memory
An increase in the severity of ADHD symptoms is linked to more severe symptoms of GAD (Tsang, et al. 2015).
Different types of phobic anxiety than those without ADHD
May inhibit impulsivity but make inattention worse (which may also make it harder to get diagnosed as this child is less likely to be disrupting class) (Pliszka et al., 1999)
Other Specific features of co-occurrence include:
Anxiety may inhibit impulsivity but make inattention worse (which may also make it harder to get diagnosed as this child is less likely to be disrupting class) (Pliszka et al., 1999)
When a person has anxiety and ADHD, they are often diagnosed later in life than those without anxiety; the presence of anxiety may inhibit impulsivity, making it less likely for the person to be diagnosed with ADHD (Katzman et al., 2017)
People with both are less likely to display off-task and hyperactive behavior
ADHD + anxiety participants showed longer reaction times (thus more difficulties with inattention) than ADHDers without anxiety (Hammerness et al., 2009)
ADHD + anxiety children scored better on response inhibition items but performed worse (than non-anxious ADHD children) on working memory tasks (Hammerness et al., 2009)
Methylphenidate improves working memory in non-anxious children but not in anxious children (Tannock and Schachar, 1995)
The presence of co-occurring ADHD negatively impacted school functioning in children with anxiety disorders. The frequency of mental health treatment in children with anxiety disorders was significantly increased in the presence of co-occurring ADHD (Hammerness et al., 2009)
The presence of anxiety may predict a poorer response to stimulant treatment for ADHD Hammerness et al., 2009)
Symptoms classified as "severely impairing" occurred at significantly higher rates in the anxiety plus ADHD group (56% compared to 45%) (Hammerness et al., 2009)
No difference in global functioning, however school functioning of children with anxiety disorders was negatively impacted by co-occurring ADHD (Hammerness et al., 2009)
Children with both had increased rates of extra help and double placement in special classes Hammerness et al., 2009)
ADHDers with anxiety disorders tend to have more severe anxiety symptoms (than non-ADHD people with anxiety disorders), earlier age of onset of anxiety, and more additional co-occurring mental health diagnoses and substance use problems than non-ADHDers with anxiety (Katzman et al., 2017)
Misdiagnosis of ADHD or Anxiety?
The most common misdiagnosis likely occurs either because one condition is missed or when ADHD-inattentive type is misdiagnosed as anxiety or vice versa. ADHD-inattentive type and GAD clinically present with similar symptoms and thus may be misdiagnosed.
Another misdiagnosis that may occur is when GAD is diagnosed; however, the person is experiencing secondary anxiety to ADHD. Secondary anxiety results from the fact that the person needs to work ten times harder than everyone else to get the work done. Anxiety can be related to missing details, assignments, or social missteps, and this is different than "primary anxiety."
ADHD and Anxiety Overlap
There are many overlapping symptoms and experiences that may cause these conditions to look like one another or for one diagnosis to be missed. Following are some of the overlapping experiences:
Inattention
Excessive worry can make it difficult to focus. The brain may be hyperfocused on fear signals and less primed to attend to other signals and cues. Difficulty regulating attention is a key feature of ADHD.
Sleep Issues
Sleep issues are common among ADHDers, and anxiety can interfere with sleep. Sleep problems, particularly insomnia and nightmares, are higher among people with GAD (Staner, 2003). Sleep issues are also common among people with ADHD; approximately 25-50% of people with ADHD struggle with circadian rhythm sleep disorders, insomnia, narcolepsy, restless leg syndrome, sleep-disordered breathing, and insomnia (Wajszilber et al., 2021). Nightmares and insomnia are also common among ADHD children (Grünwald and Schlarb, 2017). And up to 70% of children with ADHD have sleep difficulties (Sciberras, 2020).
Intrusive Thoughts
Experiencing intrusive thoughts can be a common symptom of many anxiety disorders. Intrusive thoughts are also more common in the context of ADHD (Abramovitch and Schweiger, 2009).
Digestive Issues
ADHDers have more digestive issues (Kedem et al., 2020). Digestive issues are also common in the context of anxiety and mood disorders (Shah et al., 2009).
Sympathetic Nervous System (SNS) Dominant (Fight-or-Flight)
ADHDers tend to be more SNS dominant, meaning they spend more time in the activated part of the nervous system and have a harder time getting into the "rest and digest" part of the nervous system (parasympathetic). When anxiety is present, it is also common to exist primarily in the Sympathetic mode. (To watch a video about the autonomic nervous system, see this great Khan academy series on it)
Low GABA
Speaking of the nervous system, both anxiety and ADHD are associated with low levels of GABA. Gaba is the primary inhibitory neurotransmitter within the central nervous system (Lydiard, 2003). GABA plays an important role in processing sensory information and choosing the appropriate behavioral response (Edden, 2012). When the GABA-Glutamate cycle is off, this can lead to hyperactivation within the central nervous system (hence why a person with ADHD and anxiety tends to be sympathetic nervous system dominant).
Restlessness, Agitation, and Irritability
These are common among both conditions (also related to GABA and central nervous system activation), among other things.
Difficulty Focusing and Concentrating
Both conditions involve difficulty with concentrating; however, the origin will be different. Someone with anxiety may be so overwhelmed with anxious thoughts that their executive functioning will suffer, and they may have difficulty processing additional information. For the ADHDer, even in a state of relative calm or peace, they continue to experience difficulties with attention and concentration.
How to Spot the Difference between ADHD and Anxiety
It can be difficult to tease out ADHD from anxiety, and there are several things the clinician should consider.
Primary vs. Secondary Anxiety
One of the things for the clinician to tease out is whether the person is experiencing primary or secondary anxiety. ADHD can cause anxious thoughts and worry about getting things done or the ability to get things done. If the person's worry and stress are explicitly tied to executive functioning difficulties, be aware this may be secondary anxiety associated with ADHD (vs. primary generalized anxiety disorder). . Alternatively, the person may be experiencing a co-occurring primary anxiety disorder on top of ADHD. In the case of the second option, the person's worry and anxiety will likely be more global than ADHD concerns. People with an anxiety disorder, on top of ADHD, experience broader and more general anxiety. The anxiety is not explicitly connected to ADHD difficulties and will be more generalized and pervasive in nature. They will likely also have many of the physical manifestations of anxiety (restlessness, sleep difficulties); however, given these all-mimic ADHD symptoms, the clinician must understand the triggers for worry and understand the internal and mental experience of the worry thoughts.
Consider the Proportion of the Stressor/Risk to the Worry
Determine the proportion of worry to risk/stressor. In the context of generalized anxiety disorder, the proportion of worry and anxiety to the actual risk will be disproportional. In the context of ADHD, the person may commonly experience worry, anxiety, and stress associated with executive functioning difficulties. These worries are more likely to be proportional. The person is experiencing significant difficulty completing tasks on time, making it to appointments, completing details, and so forth. Therefore, the stress associated with this is generally proportionate to the stress encountered.
Understand the Cause of Inattention
To understand the difference between ADHD and anxiety, the clinician must understand the experience of the person and determine if the difficulty with attention and focus is due to the presence of fearful, apprehensive, and all-consuming worry thoughts, or whether the person has difficulty focusing and concentrating even in the absence of worrisome or stressful thoughts (which would indicate ADHD). People with anxiety will struggle with focus and attention, but it's because their minds are so preoccupied with anxious and worry-filled thoughts. Whereas the ADHD brain struggles with focus and attention due to being easily distracted (Drake Institute).
4) The clinician should obtain a thorough clinical history. This will help to differentiate the causes of inattention and help in determining if this is a primary anxiety disorder, ADHD, or a secondary anxiety disorder associated with ADHD struggles (Drake Institute).
GAD screening tool: https://adaa.org/screening-generalized-anxiety-disorder-gad
ADHD Screening Tool: ASRS: https://psychology-tools.com/test/adult-adhd-self-report-scale
Clinical Implications
Medication
Stimulants activate the central nervous system. Anxiety can at times, be a side effect of stimulants. Possible stimulants will make anxiety worse, at which point your doctor may recommend a non-stimulant medicine for ADHD.
Screening
Clinicians should screen for ADHD-inattentive type when diagnosing anxiety. Perhaps, particularly for girls, as girls are more likely to present with both ADHD-inattentive types and present with anxiety.
Treatment
Treatment should focus on helping support executive functioning difficulties and reducing anxiety symptoms. While both conditions are treated, this will ease the burden placed on executive functioning, which will be helpful for the person.
Treatments
Medication (ADHD: stimulants and non-stimulants; GAD: antidepressants and anxiolytics)
Executive Functioning Coaching
Cognitive Behavioral Therapy and Acceptance Commitment Therapy
Bodily movement (i.e., exercise).
Mindfulness (Headspace is one of my favorite apps that teaches mindfulness).
GABA supplements (A few brands I like: Thorne and NOW for a more economical version)
References
Abramovitch, A., & Schweiger, A. (2009). Unwanted intrusive and worrisome thoughts in adults with Attention Deficit\Hyperactivity Disorder. Psychiatry research, 168(3), 230–233. https://doi.org/10.1016/j.psychres.2008.06.004
American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (DSM-5). American Psychiatric Pub.
Anxiety and Depression Association of America (ADAA). Screening for Generalized Anxiety Disorder (GAD).
Drake Institute of Neurophysical Medicine. Retrieved at: https://www.drakeinstitute.com/adhd-vs-anxiety-whats-the-difference
Edden RAE, Crocetti D, Zhu H, Gilbert DL, Mostofsky SH. Reduced GABA Concentration in Attention-Deficit/Hyperactivity Disorder. Arch Gen Psychiatry. 2012;69(7):750–753. doi:10.1001/archgenpsychiatry.2011.2280
Kedem, S., Yust-Katz, S., Carter, D., Levi, Z., Kedem, R., Dickstein, A., Daher, S., & Katz, L. H. (2020). Attention deficit hyperactivity disorder and gastrointestinal morbidity in a large cohort of young adults. World journal of gastroenterology, 26(42), 6626–6637. https://doi.org/10.3748/wjg.v26.i42.6626
Gregory KD, Chelmow D, Nelson HD, et al. Screening for anxiety in adolescent and adult women: A recommendation from the Women's Preventive Services Initiative. Ann Intern Med. 2020. doi:10.7326/M20-0580
Hammerness, P., Geller, D., Petty, C. et al. Does ADHD moderate the manifestation of anxiety disorders in children?. Eur Child Adolesc Psychiatry 19, 107–112 (2010). https://doi.org/10.1007/s00787-009-0041-8
Katzman, M.A., Bilkey, T.S., Chokka, P.R. et al. Adult ADHD and comorbid disorders: clinical implications of a dimensional approach. BMC Psychiatry 17, 302 (2017). https://doi.org/10.1186/s12888-017-1463-3
Kedem, S., Yust-Katz, S., Carter, D., Levi, Z., Kedem, R., Dickstein, A., Daher, S., & Katz, L. H. (2020). Attention deficit hyperactivity disorder and gastrointestinal morbidity in a large cohort of young adults. World journal of gastroenterology, 26(42), 6626–6637. https://doi.org/10.3748/wjg.v26.i42.6626
Mancini, C., Van Ameringen, M., Oakman, J. M., & Figueiredo, D. (1999). Childhood attention deficit/hyperactivity disorder in adults with anxiety disorders. Psychological Medicine, 29, 515-525.
Lydiard, R. B. (2003). The role of GABA in anxiety disorders. Journal of Clinical Psychiatry, 64, 21-27.
Pliszka, S. R., Carlson, C., & Swanson, J. M. (1999). ADHD with comorbid disorders: Clinical assessment and management. New York: Guilford.
Sarkis, S. M. (2015). Natural Relief for Adult ADHD: Complementary Strategies for Increasing Focus, Attention, and Motivation with Or Without Medication. New Harbinger Publications.
Schatz, D. B., & Rostain, A. L. (2006). ADHD With Comorbid Anxiety: A Review of the Current Literature. Journal of Attention Disorders, 10(2), 141–149. https://doi.org/10.1177/1087054706286698
Scriberras, E. (2020) How Can We Help Children with ADHD Get a Better Night’s Sleep? CHADD retrieved at: https://chadd.org/attention-article/how-can-we-help-children-with-adhd-get-a-better-nights-sleep/
Shah, E., Rezaie, A., Riddle, M., & Pimentel, M. (2014). Psychological disorders in gastrointestinal disease: epiphenomenon, cause or consequence?. Annals of gastroenterology, 27(3), 224–230.
Spencer, T., Biederman, J., & Wilens, T. (1999). Attention deficit/hyperactivity disorder and comorbidity. Pediatric Clinics of North America, 46, 915-927
Staner L. (2003). Sleep and anxiety disorders. Dialogues in clinical neuroscience, 5(3), 249–258. https://doi.org/10.31887/DCNS.2003.5.3/lstaner
Tannock, R., & Schachar, R. (1995). Differential-effects of methylphenidate on working-memory in ADHD children with and without comorbid anxiety. Journal of the American Academy of Child & Adolescent Psychiatry, 34, 886-896.
Tsang, T. W., Kohn, M. R., Efron, D., Clarke, S. D., Clark, C. R., Lamb, C., & Williams, L. M. (2015). Anxiety in Young People With ADHD: Clinical and Self-Report Outcomes. Journal of Attention Disorders, 19(1), 18–26. https://doi.org/10.1177/1087054712446830
Wajszilber, D., Santiseban, J. A., & Gruber, R. (2018). Sleep disorders in patients with ADHD: impact and management challenges. Nature and science of sleep, 10, 453–480. https://doi.org/10.2147/NSS.S163074
