Sleep Health

Sleep Disorders: Types, Causes & Treatment

Poor sleep is not just tiredness — it drives obesity, diabetes, heart disease, depression, and dementia. This guide covers the most common sleep disorders and how each is diagnosed and treated.

Insomnia prevalence
30–35% of adults
OSA prevalence
4–7% (many undiagnosed)
Sleep needed
7–9 hours (adults)
Impact on health
Equivalent to smoking risk

Types of Sleep Disorder

DisorderKey FeatureDiagnosis
InsomniaDifficulty falling or staying asleep >3 nights/week for >3 monthsClinical history + sleep diary
Obstructive sleep apnoea (OSA)Breathing stops repeatedly during sleep; snoring, daytime sleepinessOvernight sleep study (polysomnography or oximetry)
Restless legs syndromeOverwhelming urge to move legs at night; creeping sensationsClinical + ferritin check (low iron worsens RLS)
NarcolepsyExcessive daytime sleepiness; cataplexy (sudden muscle weakness with emotion)Sleep study with MSLT test; CSF orexin levels
Circadian rhythm disorderSleep-wake cycle misaligned with desired scheduleSleep diary; light therapy history

Sleep Apnoea — Symptoms and Diagnosis

Driving with Undiagnosed OSADriving while excessively sleepy is illegal and dangerous. In the UK and many countries, you must inform the DVLA if you have excessive daytime sleepiness. Untreated severe OSA significantly increases road accident risk.

Blood Tests for Sleep Disorders

TestWhy Ordered
Ferritin (iron stores)Low iron worsens restless legs syndrome
Thyroid (TSH)Hypothyroidism causes excessive sleepiness
FBCAnaemia causes fatigue mimicking sleep problems
Glucose / HbA1cDiabetes disturbs sleep; OSA worsens diabetes
Vitamin DDeficiency associated with poor sleep quality
Testosterone (men)OSA is associated with low testosterone
STOP-BANG Score for OSAQuick OSA screening: Snoring? Tired? Observed apnoeas? high Pressure (blood pressure)? BMI >35? Age >50? Neck circumference >40cm? Male Gender? Score ≥3 = high risk for OSA. Refer for sleep study.

Evidence-Based Treatments

ConditionFirst-Line TreatmentSecond-Line
InsomniaCBT-I (Cognitive Behavioural Therapy for Insomnia)Melatonin (short-term); low-dose medications
OSA (mild-moderate)CPAP (continuous positive airway pressure)Mandibular advancement device
OSA (positional)Positional therapy (avoid sleeping on back)CPAP if positional therapy insufficient
RLSIron supplementation if ferritin <75 ng/mLPramipexole, ropinirole; gabapentin
NarcolepsyModafinil, pitolisant (stimulants)Sodium oxybate (GHB)
Is insomnia all in the mind?
No — insomnia involves real changes in brain arousal systems, cortisol patterns, and body temperature regulation. However, thought patterns and behaviours maintain it, which is why CBT-I (not just sleep hygiene tips) is so effective.
Will CPAP cure my sleep apnoea?
CPAP treats OSA while you use it — it doesn't cure the underlying anatomy. However, significant weight loss (10–15%) can resolve OSA in many overweight patients. Bariatric surgery cures OSA in 80% of patients.
Can melatonin help insomnia?
Melatonin works best for circadian rhythm disorders (jet lag, shift work, delayed sleep phase). Evidence for primary insomnia is weaker. 0.5–1 mg (much lower than sold OTC) taken 30–60 minutes before target sleep time is most effective.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.