Narcolepsy is a chronic sleep disorder characterised by overwhelming daytime drowsiness and an irresistible need for sleep. It tends to have an onset in adolescence to early adulthood. It can significantly impact daily life, and it can also be resource-intensive and time-consuming to assess and diagnose. Although narcolepsy and ADHD are distinct conditions, they can co-occur, and both can be treated together.
There is evidence suggesting a higher prevalence of ADHD symptoms in individuals with narcolepsy. A systematic review and metanalysis published in January 2024 found that the pooled prevalence of ADHD in samples of people with narcolepsy was around 25%. This is significantly higher compared to the general population, where prevalence of ADHD is around 5%. The comorbidity may be due to overlapping symptoms such as attention deficits and executive function impairments, as well as potential neurobiological links involving the hypocretin/orexin system (see below).
What is Narcolepsy?
Narcolepsy is a neurological disorder affecting the brain's ability to regulate sleep-wake cycles. People with narcolepsy often find it challenging to stay awake for long periods, regardless of the circumstances, meaning that they experience an irresistible need for sleep. This disorder can lead to serious disruptions in daily activities and overall quality of life.
Narcolepsy is primarily caused by the loss of hypocretin-producing neurons in the hypothalamus. Hypocretin, also known as orexin, is a neurotransmitter that plays a crucial role in regulating wakefulness and REM (rapid eye movement) sleep. The loss of these neurons leads to an inability to maintain normal sleep-wake cycles, resulting in the symptoms of narcolepsy.
There are two types of narcolepsy:
Type 1 Narcolepsy: Characterised by excessive daytime sleepiness and cataplexy, often involving low levels of hypocretin, a brain chemical that regulates wakefulness.
Type 2 Narcolepsy: Involves excessive daytime sleepiness without cataplexy, typically with normal hypocretin levels.
In narcolepsy with cataplexy (Type 1), the loss of hypocretin neurons is more severe. The exact cause of this neuronal loss is not fully understood, but it is believed to involve autoimmune mechanisms, genetic predispositions, and environmental factors.
Key Symptoms of Narcolepsy
Excessive Daytime Sleepiness (EDS): The primary symptom, EDS, is characterised by persistent and overwhelming sleepiness during the day, often resulting in unintended naps.
Abnormal REM sleep. Dreaming can occur right after falling asleep, rather than at the end of a sleep cycle which is typically around 90 minutes. This intrusion of sleep leads to the experience of sleep paralysis and hallucinations as described below.
Cataplexy: This sudden, brief loss of muscle tone can cause weakness and loss of voluntary muscle control. It is usually triggered by strong emotions such as laughter or surprise. It can affect large or small muscles, leading to anything from falling to muscle weakness.
Sleep Paralysis: A temporary inability to move or speak while falling asleep or upon waking.
Hypnopompic and Hypnogogic Hallucinations: Vivid, often frightening, dream-like experiences that can involve visual, auditory, tactile, or olfactory (smell) sensations. They occur while falling asleep or waking up.
Disrupted Nighttime Sleep: Despite excessive daytime sleepiness, individuals with narcolepsy often experience fragmented sleep at night.
Diagnostic Criteria and Assessment
Diagnosing narcolepsy involves a comprehensive evaluation, including:
Epworth Sleepiness Scale (ESS): This screening questionnaire may be used to gauge levels of sleepiness during the day.
Medical and Sleep History: Detailed information about sleep patterns, symptoms, and any relevant family history.
Polysomnography (PSG): An overnight sleep study that records brain activity, eye movements, muscle activity, heart rate, and breathing during sleep.
Multiple Sleep Latency Test (MSLT): Conducted the day after a PSG, this test measures how quickly a person falls asleep in a quiet environment during the day. It helps determine the presence of sleep-onset REM periods, which are indicative of narcolepsy.
The combination of these assessments helps in accurately diagnosing narcolepsy and differentiating it from other sleep disorders.
Treatment Options for Narcolepsy
While there is no cure for narcolepsy, various treatments can help manage symptoms and improve quality of life:
Medications:
Stimulants:
Modafinil is wakefulness-promoting medication that works on a number of neurotransmitter systems including dopamine, norepinephrine, serotonin, glutamate and GABA, as well as histamine
Methylphenidate and amphetamines can also be used to treat narcolepsy
Antidepressants: Certain antidepressants, such as SSRIs, SNRIs, and tricyclics can help manage cataplexy, sleep paralysis, and hallucinations.
Lifestyle Modifications:
Scheduled Naps: Taking short, regular naps can help manage daytime sleepiness.
Good Sleep Hygiene: Maintaining a consistent sleep schedule, creating a restful sleep environment, and avoiding caffeine and alcohol before bedtime.
Behavioural Therapy:
Cognitive Behavioural Therapy (CBT): This can help address the psychological impact of living with narcolepsy and improve coping strategies.
Support and Education:
Support Groups: Connecting with others who have narcolepsy can provide emotional support and practical advice.
Education: Educating affected people and their families about the condition can help manage expectations and improve understanding.
Managing Narcolepsy and ADHD Together
When narcolepsy and ADHD co-occur, managing both conditions can be challenging but achievable with a comprehensive approach:
Medication Management: Stimulants used for ADHD, such as methylphenidate and amphetamines, can also be effective for narcolepsy. Modafinil can be used in conjunction with methylphenidate or amphetamines to enhance wakefulness and manage symptoms more effectively. Modafinil can occasionally be used off-label as a treatment for ADHD.
Integrated Treatment Plan: Combining medication with behavioural strategies can be beneficial. For example, using stimulant medications alongside behavioural therapies can help manage ADHD symptoms while also addressing excessive daytime sleepiness due to narcolepsy.
Routine and Structure: Maintaining a structured daily routine, including scheduled naps and consistent sleep and waking times can help manage symptoms of both conditions.
Regular Follow-ups: Regular consultations with healthcare providers including a sleep specialist and psychiatrist can ensure that treatment plans remain effective and adjusted as needed to address any changes in symptoms or side effects.
Holistic Support: Incorporating therapy and educational resources, as well as finding a community of people also affected by narcolepsy and ADHD can aid in addressing emotional and practical challenges of living with both conditions.
Conclusion
With proper assessment, diagnosis and management, people with narcolepsy without or without ADHD can lead fulfilling lives. If you suspect you may have narcolepsy, seeing your GP is the first step to accessing screening and assessment.
See this fact sheet from the National Institute of Neurological Disorders and Stroke for information about narcolepsy characteristics, assessment, and treatment.
MyNarcoplepsyTeam has information about the coexistence of ADHD and narcolepsy
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