Research shows that 17-19 hours of wakefulness produces cognitive impairment equivalent to a blood alcohol level of 0.05% — and chronic sleep deprivation compounds this significantly. If insomnia is seriously affecting your ability to work safely, a sick note may be appropriate.
THE MEDICAL RECOGNITION OF INSOMNIA
Chronic insomnia disorder is a recognised medical condition requiring clinical assessment and treatment. It's not simply "trouble sleeping" — it involves persistent difficulty falling or staying asleep, despite adequate opportunity to sleep, with significant impact on daytime functioning.
WHEN INSOMNIA JUSTIFIES A SICK NOTE
A fit note for insomnia is most appropriate when:
● Your insomnia is so severe that you are experiencing dangerous levels of fatigue
● You are at risk of a workplace accident due to impaired alertness (particularly relevant for drivers, machine operators, healthcare workers, or anyone working at heights)
● Your insomnia is a symptom of an underlying condition (depression, anxiety, sleep apnoea) that itself warrants a sick note
● You are undergoing treatment (CBT for insomnia, medication adjustment) that temporarily worsens your daytime functioning
SAFETY-CRITICAL ROLES
If you drive for a living, operate heavy machinery, or work in healthcare or emergency services, severe sleep deprivation creates a genuine safety risk — not just for you but for colleagues and the public. This is a strong clinical basis for a short-term fit note while insomnia is being treated.
GETTING HELP FOR INSOMNIA
A sick note is not a long-term solution for insomnia. We always encourage patients to access appropriate treatment:
● CBT-I (Cognitive Behavioural Therapy for Insomnia) is the gold-standard first-line treatment
● Your NHS GP can refer you to sleep services
● Many sleep clinics offer waiting list referrals for shorter waits
Dr Sick can issue a short-term fit note while you access treatment. Visit drsick.co.uk.
