ADHD vs. Anxiety: Key Differences

ADHD affects 22 million people in the US, while anxiety affects 6.8 million. However, it can be challenging to identify the differences between the two.

Around 25% of individuals diagnosed with ADHD also fit the criteria for anxiety disorders. Because of this, misdiagnosis and improper treatment may happen.

Knowing how ADHD and anxiety are similar and different helps in making the correct diagnosis and managing them well. This article will explain the main distinctions, where they overlap, and how to treat both conditions.

Shared Symptoms of Anxiety and ADHD

Shared symptoms of anxiety and ADHD include sleep-related symptoms, neurological factors, and cognitive impairments. Whenever such symptoms overlap, people may mistake one diagnosis for the other.

Sleep-Related Symptoms

Both ADHD and anxiety involve sleep disturbances, particularly insomnia. It is a significant feature in about 70–80% of people with anxiety. Excessive worry and fear can make it difficult to fall asleep and stay asleep all night.

In the same manner, about 44.4% of adults with ADHD also experience insomnia, and it’s more common in people who have more severe ADHD symptoms. People with ADHD often have trouble sleeping due to feeling a sudden rush of energy right when they lie down in bed. Other times, they find it challenging to get their mind to relax when it’s time to sleep.

Neurological Factors

Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. GABA neurons in the amygdala play a role in controlling anxiety. When GABA receptors are less active, it may result in anxiety-like behaviors.

Similarly, a study discovered that people with ADHD also have lower levels of GABA compared to those without the condition. Reduced GABA activity may indicate deficits in cortical inhibition, which is essential for filtering sensory information and choosing the proper behavioral responses.

Cognitive Impairments

The root causes differ, but both ADHD and anxiety can make it hard to focus and concentrate.

In anxiety, concentration problems often arise due to excessive worry, which distracts attention and worsens anxiety symptoms. These difficulties increase the clinical severity of anxiety through impaired role functioning and perceived distress.

In the same way, inattentiveness, or difficulty in concentrating, is a primary symptom of ADHD. People with ADHD have trouble focusing because of issues with their brain chemistry. Those with ADHD have lower levels of dopamine and norepinephrine, which are essential for keeping the brain alert and focused.

Anxiety vs. ADHD: Key Differences

It's essential to know the different traits of anxiety and ADHD so that individuals can get the proper treatment. This section examines how they differ in signs and symptoms, causes, age of onset, and medications used to treat them.

Signs and Symptoms

One key difference between anxiety and ADHD are the signs and symptoms associated with the conditions. The following sections will review some of the features of anxiety and ADHD.

Anxiety Signs and Symptoms

Those who suffer from anxiety may exhibit the following symptoms:

• Excessive fear or worry about a particular situation
• Feelings of restlessness, tension, and irritability
• Difficulties in decision-making
• Experiencing heart palpitations, tremors, trembling, or perspiration
• Difficulty in sleeping

ADHD Signs and Symptoms

Meanwhile, symptoms of ADHD change over time, but below are the general signs and symptoms:

• Difficulty organizing tasks, paying attention, and following instructions
• Forgetting daily routines
• Frequent fidgeting and talking
• Difficulty sitting still for long periods
• Constant movement in younger children
• Restlessness and impulsivity
• Difficulty waiting for turns or listening to directions

Causes

Anxiety and ADHD also differ in terms of their causes. Let’s look into this further:

Causes of Anxiety

Anxiety can come from different reasons, like medical issues or life experiences.

The following medical conditions may be associated with anxiety:

• Diabetes: According to a meta-analysis, adults aged 16 and older and with diabetes are more likely to experience anxiety problems and have more severe symptoms of anxiety.
• Irritable bowel syndrome: A study found that compared to healthy individuals, 39% of those with IBS had a threefold increased risk of anxiety, while 23% had co-occurring anxiety disorders.
• Drug and/or alcohol withdrawal or misuse: Around 10 to 20% of those with anxiety disorders misuse alcohol or other drugs. However, most individuals with anxiety and alcohol disorders believe their anxiety preceded alcoholism.
• Chronic obstructive pulmonary disease (COPD): Being unable to breathe deeply due to COPD can cause anxiety. The prevalence of anxiety in COPD patients varies between 7 and 50%.
• Heart disease: Patients with cardiovascular conditions, such as coronary artery disease (CAD) and heart failure, frequently experience anxiety.
• Thyroid problems: Anxiety is prevalent in approximately 60% of individuals with hyperthyroidism, compared to up to 40% in those with hypothyroidism. Those with an overactive thyroid are also more likely to experience specific anxiety disorders.

There are other risk factors for the development of anxiety, such as:

• Stress: Having high levels of cortisol and other stress hormones and long-term activation of the stress response system may disrupt almost all of the body’s functions. As a result, this may put you at a higher risk for anxiety.
• Traumatic events: Trauma survivors may experience anxiety in various forms, ranging from heightened generalized worries to episodes of panic attacks.
• Having relatives and/or family members diagnosed with anxiety: Anxiety disorders are known to run in families. While the exact mechanisms are unclear, factors such as genetic inheritance, anxiety-promoting behaviors, and shared negative environments all likely contribute to this association.

Causes of ADHD

Similar to anxiety, a combination of factors is likely to be responsible for ADHD. Such factors may include:

• Genetics: Family and twin studies estimate the heritability of ADHD to be around 80%, indicating a strong genetic component in its development.
• Differences in brain structure: Children with ADHD often have smaller overall brain size, slower brain maturation, and reduced volume in areas like the amygdala, hippocampus, and frontal lobe. These structural differences can impact emotion regulation, attention, and social behavior.
• Imbalances in neurotransmitter levels: ADHD may be caused by lower dopamine levels in the brain, which may alter the brain's processing of motivation and reward.

Specific individuals are also thought to be more prone to ADHD, including those with:

• Premature birth: A study discovered that children born between 37 and 38 weeks had considerably higher ADHD symptom scores than those born between 39 and 41 weeks.
• Low birth weight: A study found that low birth weight is independently associated with the severity of ADHD symptoms. After controlling for external factors, this link remains, which suggests that fetal growth restriction and/or environmental factors may cause ADHD.
• Brain injury: According to a study, traumatic brain injury significantly increases the risk of developing ADHD, with prevalence rates up to 50% post-injury.
• Epilepsy: Children with epilepsy are at risk of developing attention difficulties and/or ADHD, with clinical studies indicating a prevalence rate of up to 40%.

Diagnosis

The way doctors diagnose anxiety and ADHD is quite different, though both conditions require careful evaluation by healthcare professionals using the DSM-5 criteria by the American Psychiatric Association.

Diagnostic Criteria for Anxiety

Anxiety can manifest in different forms, ranging from nonpathological to pathological. Pathological anxiety, such as generalized anxiety disorder (GAD), is distinguished by its excessive and persistent nature, interfering with daily functioning.

According to the DSM 5, the diagnostic criteria for GAD are as follows:

• Excessive worry and anxiety for at least 6 months about specific events or activities
• Difficulty in controlling their worry
• Anxiety and worry are linked to at least three of the following symptoms: restlessness, fatigue, difficulty concentrating, irritability, muscle tension, sleep disturbances
• Symptoms of anxiety result in clinically significant distress or impairment in occupational, social, and other important areas of functioning
• Disturbance is not caused by a substance or another medical condition
• Another mental disorder cannot explain the disturbance

Generalized anxiety disorder differs from nonpathological anxiety in several ways:

Diagnostic Criteria for ADHD

On the other hand, DSM-5 ADHD diagnostic criteria include:

• Persistent inattention and/or hyperactivity-impulsivity that interferes with functioning or development
• At least six symptoms (5 for individuals aged 17 and older) for inattention, persisting for more than 6 months and negatively impacting social or academic/occupational activities
• At least six symptoms (5 for individuals aged 17 and older) for hyperactivity/impulsivity, persisting for more than 6 months
• Symptoms are present before age 12 and occur in 2 or more settings
• Clear interference with social, academic, or occupational functioning
• Not better explained by another mental or psychotic disorder

The table below discusses inattention and hyperactivity/impulsivity symptoms more thoroughly:

Medications

Lastly, prescribed medications given for anxiety and ADHD are different. Doctors may elect to use antidepressants and benzodiazepines to help with anxiety, while stimulant and non-stimulant medications are typically used for treating ADHD.

Anxiety Medications

The following medications are commonly used to treat anxiety disorders:

Antidepressants

These medications address the chemical imbalances in the brain that contribute to anxiety. Selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs) are the most frequently used medications for anxiety.

SSRIs and SNRIs increase the availability of chemicals in the brain which alter your mood. This helps to control symptoms of anxiety and prevent anxiety attacks. In the absence of adverse effects, most users of antidepressants are advised to take them for 6–12 months. It may take several weeks for the medications to take full effect.

Benzodiazepines

Benzodiazepines, also known as sedatives, enhance the calming effects of certain chemicals in the brain and nervous system.

These medications are generally used to reduce anxiety in the short term and are sometimes prescribed to treat sleep difficulties. They are not suggested for long-term use due to their addictive properties.

ADHD Medications

Common medications used to treat ADHD include methylphenidate, lisdexamfetamine, dexamfetamine, atomoxetine, and guanfacine.

Methylphenidate

Methylphenidate is a stimulant medication used for ADHD and is prescribed for adults, teenagers, and children over 5 years old. It can be taken as immediate-release tablets or modified-release tablets.

Lisdexamfetamine

Lisdexamfetamine is another type of stimulant medication used to enhance concentration and attention and reduce impulsive behavior. This medication can be given to individuals with ADHD if treatment with methylphenidate is not effective. This medication is typically dosed once a day given its long acting duration.

Dextroamphetamine

Dextroamphetamine functions similarly to lisdexamfetamine. It may be offered to adults, teenagers, and children over 5 with ADHD.

Dextroamphetamine can be taken as a tablet 2 to 4 times each day, but also is available in an oral solution or transdermal patch.

Atomoxetine

Atomoxetine is a type of non-stimulant medication. It is an SNRI and has a different mechanism of action compared to other ADHD medications. Atomoxetine raises noradrenaline levels in the brain, which helps improve focus and control impulses.

Atomoxetine is available in capsules and is usually taken 1–2 times daily.

Guanfacine

Guanfacine, another type of non-stimulant, works by improving attention and also reducing blood pressure. It is usually taken as a tablet once daily, either in the morning or at night.

Guanfacine is not suggested for adults with ADHD unless a specialist gives advice.

Wrap Up

It is easy to mistake ADHD and anxiety for one another because of their shared symptoms in cognitive impairments, sleep-related symptoms, and neurological factors. ADHD-related sleep troubles often result from hyperactivity. Meanwhile, anxiety-driven insomnia arises from excessive worry.

ADHD reduces cortical inhibition, and anxiety increases fear responses due to low GABA levels. Although both conditions involve trouble concentrating, ADHD results from brain chemical imbalances, while anxiety distracts focus with excessive worry.

Another difference between ADHD and anxiety is their diagnosis. Anxiety diagnosis focuses on persistent worry, while ADHD diagnosis focuses on inattention and hyperactivity-impulsivity. Treatment also differs, with anxiety managed by antidepressants or benzodiazepines and ADHD treated with stimulant and/or non-stimulant medications.

FAQs on ADHD vs. Anxiety

How do ADHD medications affect anxiety?

Stimulant medications for ADHD can make anxiety symptoms worse because you may experience side effects like feeling more nervous or tense. Non-stimulant medications like Strattera or Qelbree are usually a better choice for people who also have anxiety.

Do diet and nutrition influence ADHD or anxiety symptoms?

Dietary patterns influence both ADHD and anxiety symptoms. A study found that diets rich in vegetables, fruits, and minimally processed foods reduce anxiety symptoms. Another study found that healthy eating patterns are inversely associated with ADHD.

Can untreated ADHD lead to anxiety disorders?

Yes, challenges from untreated ADHD symptoms can make people feel inadequate and worthless. These emotions may develop into anxiety and depression.

Is there a treatment option that can be used for both anxiety and ADHD?

Cognitive Behavioral Therapy (CBT) is proven to be an effective treatment for both ADHD and anxiety. A study stated that CBT is the gold standard for treating anxiety disorders. Another study found that CBT reduced ADHD symptoms and improved quality of life.

Is there an evaluation tool to distinguish ADHD vs. anxiety in adults?

Evaluation tools that can be used to distinguish ADHD vs. anxiety in adults may include the Adult ADHD Self-Report Scale (ASRS-v1.1) for ADHD and the Generalized Anxiety Disorder Scale (GAD-7) for anxiety.