Narcolepsy and ADHD are two distinct disorders, but they’re commonly seen together and may share similar underlying mechanisms.

At first glance, narcolepsy and attention deficit hyperactivity disorder (ADHD) may not seem to have much in common. We know that narcolepsy causes excessive sleepiness, while ADHD is best known for hyperactivity.

But research suggests that these two neurological disorders do have some overlap and may even share some underlying mechanisms.

It’s not uncommon to have both narcolepsy and ADHD. In fact, up to 30% of people with narcolepsy also meet the criteria for ADHD (compared to only 4.4% of the general population).

But even if you don’t have both disorders entirely, there’s still some symptom overlap.

ADHD-like symptoms are very common in people with narcolepsy. Some evidence suggests that ADHD symptoms are twice as likely in children and adolescents with narcolepsy.

For instance, the excessive daytime sleepiness seen in narcolepsy can lead to inattention, poor executive function, and impulse control problems — all symptoms that mimic ADHD and respond well to stimulant medications.

Similarly, people with ADHD often have sleep-related problems. Research suggests that sleep problems are reported in an estimated 25%–50% of individuals who have ADHD. And one study found that 3 of the 15 child participants with ADHD showed narcolepsy-like symptoms during sleep.

Sometimes the symptom overlap between the two disorders can lead to misdiagnosis.

Are ADHD and narcolepsy related?

Narcolepsy and ADHD are two distinct disorders, but some evidence suggests they may share some common mechanisms.

One underlying mechanism may involve the neurotransmitter noradrenaline. It’s believed that ADHD is linked to the dysregulation of the neurotransmitters dopamine and noradrenaline. Research suggests that noradrenaline dysfunction may also lead to changes in REM sleep, similar to what’s observed in narcolepsy.

Both ADHD and narcolepsy are effectively treated with stimulants, which target these specific neurotransmitters.

Another similarity between the two disorders relates to how iron is metabolized in the body. Research suggests that low iron levels are commonly seen in both ADHD and narcolepsy and that low iron levels are also linked to greater symptom severity.

Some evidence also points to a genetic link between narcolepsy and ADHD.

Some people with ADHD and hypersomnia (excessive daytime sleepiness or prolonged nighttime sleep) meet the diagnostic criteria for type 2 narcolepsy, also called narcolepsy without catalepsy (sudden, brief episodes of muscle weakness triggered by strong emotions).

These individuals lack a specific genetic trait seen in people with type 1 narcolepsy (narcolepsy with catalepsy) as well as those with type 2 narcolepsy without ADHD. This might suggest that people with ADHD and hypersomnia have their own subtype of type 2 narcolepsy.

ADHD and narcolepsy symptoms

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness occurring alone or with sudden, brief episodes of muscle weakness triggered by strong emotions (cataplexy).

There are two major types of narcolepsy:

  • Type 1 narcolepsy (narcolepsy with cataplexy): Type 1 involves low levels of hypocretin (brain chemical that regulates sleep and wakefulness) or the presence of cataplexy and excessive daytime sleepiness.
  • Type 2 narcolepsy (narcolepsy without cataplexy): Type 2 involves excessive daytime sleepiness without cataplexy and with normal hypocretin levels.

ADHD is a neurodevelopmental disorder characterized by difficulty with paying attention, impulsivity, and hyperactivity.

ADHD diagnostic criteria divide people into the following types:

  • inattentive
  • hyperactive-impulsive
  • combined presentation

Some symptoms that may be seen in both narcolepsy and ADHD include:

  • excessive daytime sleepiness
  • difficulty paying attention or staying focused
  • impulsivity or difficulty controlling behavior
  • difficulty with organization and time management
  • hyperactivity or restlessness
  • sleep disturbances, such as difficulty falling asleep or staying asleep

There are some distinct differences between the two disorders as well. For instance, “sleep attacks” (suddenly falling asleep without warning) and cataplexy are distinct narcolepsy symptoms that aren’t typical ADHD symptoms.

There are several medications that can be used to treat both narcolepsy and ADHD.

Certain stimulants, such as modafinil (Provigil) and armodafinil (Nuvigil), are often used to increase alertness and wakefulness in narcolepsy. These medications may also be prescribed off-label to help manage ADHD symptoms, such as inattention and impulsivity.

The stimulant methylphenidate (Ritalin) is often used to treat ADHD and may be used off-label for narcolepsy to help with daytime sleepiness.

Other medications that may be used to treat both narcolepsy and ADHD include amphetamines, such as dextroamphetamine (Dexedrine) and lisdexamfetamine (Vyvanse), and non-stimulant medications, such as atomoxetine (Strattera).

Though two distinct disorders, narcolepsy and ADHD do have symptom overlap and may also share some underlying mechanisms. Both are neurodevelopmental disorders that may feature daytime sleepiness, inattention, and poor executive function.

If you have any symptoms of narcolepsy or ADHD, consider reaching out to a healthcare clinician to get a professional diagnosis. Both disorders are highly treatable, and the right treatment may help you manage your symptoms and improve your quality of life.