We’re continuing today with the Comorbidity Series, a monthly series of posts about ADHD and comorbidity with other common psychiatric conditions. You can see all of the posts here.

Comorbidity is the occurrence of two or more psychiatric and/or neuropsychological conditions in a person. If a person has ADHD and depression, the conditions are considered comorbid.

Comorbidity can be tough! It makes diagnosis difficult, especially when those two or more conditions present with similar manifestations. Then it can be difficult to say “what’s the ADHD” and “what’s the other condition”.

Today we’re talking ADHD and Generalized Anxiety Disorder, which have many overlapping manifestations and can be extremely difficult to diagnose together.

Defining Each Condition

Attention Deficit Hyperactivity Disorder (ADHD) is a neuropsychological disorder characterized by difficulty with paying attention, hyperactivity, impulsivity, and/or difficulty controlling or regulating emotions. ADHD is broken into three categories (or presentations): Primarily Inattentive, Primarily Hyperactive-Impulsive, and Combined.

Generalized Anxiety Disorder (GAD) is a psychological condition characterized by relentless worry about a variety of external and internal factors in one’s life. It may include worrying about money, health, relationships, work, or safety. People who have GAD find it difficult to manage racing thoughts and general nervousness, and may experience a variety of physical symptoms like stomachaches, headaches, and jaw aches caused by clenching.

How Do I Know if I Have Anxiety?

Anxiety is how the body responds to stress. It’s typically a fear-centered reaction of what might happen or what’s to come in the future.

Everyone experiences anxiety at some point. We all feel worried about things and we all feel stress.

But having an anxiety disorder means that you have persistent and recurring feelings of worry or fear, and these may be around specific types of scenarios or more generalized.

These feelings of worry or fear may make it difficult or impossible for you to partake in daily life activities. They may cause anxiety attacks, panic attacks, compulsive behaviors, or avoidant behaviors, among other effects.

The types of anxiety include:

  • Panic Disorder
  • Generalized Anxiety Disorder
  • Social Anxiety Disorder
  • Obsessive Compulsive Disorder
  • Post-Traumatic Stress Disorder
  • Phobias
  • Hypochondria
  • Separation Anxiety

Today we’re comparing ADHD and Generalized Anxiety Disorder. Subscribe if you’d like to learn more about ADHD and other anxiety disorders in upcoming Comorbidity Series posts!

Comparing ADHD and GAD

ADHD and GAD have quite a few manifestations in common, and can be difficult to diagnose and treat because of this. It’s estimated that around 50% of ADHDers also experience some kind of anxiety disorder.

When you compare ADHD and GAD you’ll find that they can present with the following manifestations:

ADHDGAD
Difficulty with attention or focusxx
Poor memoryxx
Internalized/externalized restlessnessxx
Trouble with sleepxx
Irritabilityxx
Difficulty with task activationxx
Seeking out variety or excitementx 
Headaches and stomachaches x
Persistent fatiguex 
General nervousness x
Fearfulness of change x

Though they have much in common, the key difference can be found in the causes of the manifestations. ADHDers and those with GAD may experience the same things, but not necessarily for the same reasons.

Difficulty with Attention or Focus

A marker of ADHD is difficulty with maintaining attention on singular tasks for too long (not counting hyper-focus capabilities). This is due to a neurological short-circuit in the executive functioning skill known as attentional control.

People with ADHD may find it difficult to hold attention on a single task, and may get easily distracted by other environmental factors or just their own thoughts. This can occur with things that appear boring, but also with things that appear interesting. It’s essentially out of the control of the ADHDer.

In contrast, GAD may come with difficulty maintaining attention because the person who has it may be so lost in their worries or fears that they are unable to focus on other tasks. Difficulty with attention may occur when the person with GAD is experiencing anxiety, and not at other times.

Poor Memory

Many people with ADHD experience very poor memory and difficulty pulling up relevant information when they are set to perform a task or activity.

This is due to deficits in working memory, which is essentially a short-term storage tank that holds information as it’s learned and when it’s needed for action.

With anxiety, memory loss may occur due to the nature of the body’s stress response. Repeated overproduction of adrenaline and cortisol in response to real or perceived threats can overtax the brain’s ability to formulate new memories.

Internalized/Externalized Restlessness

Adults who have hyperactive or combined type ADHD don’t typically experience hyperactive episodes in the same way children do.

Children may run around or be unable to sit at all. As we age, we tend to internalize our hyperactivity and it is more often exhibited as internal-focused restlessness or subtle fidgetiness.

Adults with ADHD may feel like they are humming or buzzing, and in turn may become irritable if they have no outlet. They may also fidget in their chairs – rocking, spinning, crossing and uncrossing legs, bouncing knees.

While people with ADHD can feel hyperactive or restless any time and it tends to strike at random, people with GAD may feel restless specifically when they are experiencing an anxiety episode. They may become fidgety or feel the internal humming if they are feeling fearful or stressed about something.

ADHDers and people with anxiety may experience racing thoughts as well, but the nature of these thoughts can be different.

With ADHD, the thoughts may jump from topic to topic and appear random to an outsider but feel easily connected by the ADHDer. With anxiety, the thoughts are typically intrusive and centered around what is making someone feel anxious.

Trouble with Sleep

Sleep troubles are incredibly common among ADHDers. It’s estimated that up to 80% of adults with ADHD may experience difficulty with sleeping – including falling asleep, staying asleep, waking up, and staying awake during the day.

There are some theories that executive dysfunction may be the cause. ADHDers have difficulty with activation, which may mean they can’t activate themselves to go to bed or to wake up in the morning.

Many people with ADHD may also experience delayed sleep phase disorder, or insomnia, in part because their brains are more active at night. They may have trouble falling asleep because their thoughts are racing due to hyperactivity.

With GAD, sleeping problems tend to occur when the person who has it experiences a state of mental hyperarousal at night. Their mind is so active and consumed with fears and worries that they are unable to relax enough to sleep.

GAD can also cause a person to get less rapid eye movement (REM) sleep, which is critical in making adults feel rested and refreshed. They also may be more likely to experience nightmares that cause waking in the middle of the night.

Not sleeping may in turn cause more anxiety throughout the day, creating a vicious cycle of anxiety and sleeplessness.

How Do You Tell ADHD and GAD Apart?

ADHD and GAD have so much in common, and can both arise in childhood, and they occur so often together, that many people who have ADHD can go years without knowing it because their anxiety masks or mimics their ADHD manifestations.

They may appear more outwardly organized and “put together” because they have such anxiety about disorganization that they develop intense coping mechanisms throughout their life. If strong enough, anxiety can curb some common ADHD manifestations like impulsivity. Or they may appear to have ADHD manifestations that are attributed solely to anxiety, like fidgetiness and irritability.

And anyone who experiences both ADHD and anxiety may have a difficult time picking apart which common manifestations belong to which condition at any given time.

Doctors who are looking to determine if there is a comorbid diagnosis of ADHD and GAD, or one or the other, will look at when manifestations first began. ADHD tends to begin early, by age 10-12, whereas GAD is more likely to begin in teenage years or adulthood.

A diagnosing doctor will also question when the manifestations occur and what’s causing them. Is it seemingly random, or does there appear to be a pattern?

As explained above, people with ADHD will experience most of their manifestations randomly and uncontrollably. Attention can wander, restlessness can settle in, and sleep can be lost at any time. A person with GAD might experience these manifestations randomly as well, but they can come on more strongly while they are feeling anxious and not so much at other times.

Anxiety also tends to present with physical manifestations like upset stomach or indigestion, headache, muscle tension, heart palpitations, and trembling or difficulty with muscle control.

Is GAD a Comorbidity or a Secondary Manifestation?

While it’s possible for a person to have both ADHD and GAD at the same time, in many cases a person’s anxiety isn’t necessarily a second condition but rather can be considered a secondary manifestation of the ADHD.

This may be the case if the person who has ADHD and GAD has a tendency to experience anxiety that surrounds their ADHD manifestations.

For example, a person with both may feel great anxiety about their job. They may feel anxious about managing emails, organizing their to do list, making phone calls, planning a new project, etc.

These nervous feelings might be due to the ADHDer not knowing if they will be able to activate to get their work started, or stay on task, or get things done on time because they have had difficulty in the past. Thus, the anxiety isn’t about activities in general – it’s specifically anxiety about their ability to execute on these activities.

Another example is an ADHDer who tends to overprepare for things. They might make many plans and lists for something as simple as an outing to a park. They may bring extra food and water and medication and maybe even create a backup plan for rain.

This could potentially be attributed to the ADHDer’s past experience with under-preparedness because of their difficulty with planning and organization and working memory. They aren’t nervous about going to the park – they’re nervous about forgetting something and being caught in a surprise situation.

Treating ADHD and GAD

There are two schools of thought on treating ADHD and GAD together:

  1. Treat the more debilitating or intrusive condition first, then introduce treatment for the other condition when the first one has stabilized
  2. Treat the ADHD first in hopes that it may lessen the severity of GAD

The approach will differ from person to person based on whether the diagnosing doctor believes the anxiety stems from the ADHD, or presents on its own.

An important part of treatment may be to identify which manifestations are being caused by which condition. This can change the tactics used to manage them. A symptom diary may be a useful tool in this regard. One would use it to log when manifestations arise and in what situations – what happens and what else is going on in the environment at the time.

ADHD is typically managed with any combination of medication (either stimulant or non-stimulant), coaching, Cognitive Behavioral Therapy (CBT), and group support.

A possible side effect of stimulants is an increase in anxiety. However, stimulants should not be ruled out in treating someone with both ADHD and GAD. For some people, the physical symptoms they experience when newly starting a stimulant – dry mouth, racing heart, jitteriness – can be mistaken for anxiety. In reality, these might be purely physical reactions to the stimulant that can subside in a matter of days or weeks.

Anxiety is typically managed with anti-anxiety medications, with popular options including benzodiazepines, SSRIs, and MAOIs, and Cognitive Behavioral Therapy (CBT). Many people with ADHD and GAD take both ADHD medication and anti-anxiety medication to treat both at the same time with great success.


References, in no particular order or citation style:

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