Does Functional Neurological Disorder Affect Sleep?
Yes, sleep disturbances are highly prevalent in FND, affecting approximately 58% of patients, and poor sleep quality independently worsens functional impairment even after accounting for depression. 1
Prevalence and Characteristics of Sleep Disturbance in FND
Sleep problems are a common and clinically significant feature of FND:
89% of FND patients report clinically significant poor sleep quality, with characteristic patterns including low sleep efficiency (averaging 65%) and reduced total sleep time (averaging 6 hours per night). 2
Sleep disturbances frequently predate the FND diagnosis in 46.7% of patients, though symptoms often worsen after diagnosis, suggesting both a predisposing and perpetuating role. 3
Sleep quality independently predicts functional impairment, accounting for 16% of the variance in FND-related disability even after controlling for mood symptoms like depression. 2 This demonstrates that sleep disturbance is not merely a secondary consequence of comorbid depression but has direct clinical relevance.
Clinical Impact on FND Symptoms
The relationship between sleep and FND operates bidirectionally:
Poor sleep acts as a perpetuating factor that exacerbates core FND symptoms, cognitive difficulties, fatigue, anxiety, and pain. 4, 5
Addressing sleep deficiency is essential when managing cognitive symptoms in FND, as sleep deprivation directly impairs attention, memory, and concentration—symptoms commonly reported by FND patients. 4, 5
Sleep disturbances correlate with lower quality of life and increased symptom severity, particularly in patients with psychogenic non-epileptic seizures (PNES), who show poorer subjective sleep quality and higher insomnia rates compared to epilepsy controls. 1
Integration into FND Treatment
Current consensus guidelines recognize sleep as a treatment target:
The biopsychosocial framework for FND treatment should address sleep as a contributing biological factor alongside psychological and social elements. 4, 5
A "24-hour approach to therapy" is recommended, meaning rehabilitation strategies must account for sleep-wake patterns and their impact on symptom management throughout the daily routine. 6
Structured daily routines help prevent cognitive overload and may improve sleep quality by establishing consistent sleep-wake schedules. 7
Common Pitfalls
Failing to routinely assess and monitor sleep disturbances in FND patients represents a missed opportunity for intervention, as sleep problems are modifiable and directly impact functional outcomes. 1, 3
Assuming sleep problems are solely due to depression or anxiety overlooks the independent contribution of sleep disturbance to FND-related disability. 2
Not recognizing that sleep disturbances may worsen after FND diagnosis means clinicians should actively monitor for changes rather than assuming static symptom patterns. 3