What could be causing me to wake up between 3-5am consistently?

Waking Between 3-5am: Causes and Clinical Approach

Consistently waking between 3-5am is most commonly caused by sleep maintenance insomnia, Advanced Sleep Phase Disorder (ASPD), or underlying medical/psychiatric conditions, with age-related circadian rhythm changes being particularly important in older adults.

Primary Sleep-Related Causes

Advanced Sleep Phase Disorder (ASPD)

• ASPD is characterized by wake times between 2:00am to 5:00am, coupled with early sleep onset (6:00pm-9:00pm), and affects 1-7% of middle to older-aged adults 1
• The pathophysiology involves a shortened endogenous circadian period (less than 24 hours), reduced evening light exposure, and genetic factors including mutations in circadian clock genes (hPer2 and CK1 delta) 1
• Age-related changes cause the circadian clock to advance, with the endogenous temperature nadir and hormone secretion occurring at earlier clock hours 1
• Diagnosis requires at least 1 week of sleep diary or actigraphy documentation showing the advanced sleep-wake pattern 1

Sleep Maintenance Insomnia

• Early morning awakening with inability to return to sleep is a core feature of chronic insomnia disorder, particularly common in older adults 1
• The interaction between reduced homeostatic sleep drive and weakened circadian arousal signals in the early morning hours contributes to this pattern 1
• Approximately 35.5% of the general population reports awakening at least 3 nights per week, with 23% experiencing nightly awakenings 2
• Chronic insomnia requires symptoms present at least 3 nights per week for at least 3 months, causing clinically significant distress or functional impairment 1

Medical and Psychiatric Conditions

Psychiatric Disorders

• Depression and anxiety disorders are frequent comorbidities with early morning awakening patterns 1
• Psychiatric conditions have insomnia rates as high as 50-75%, with a bidirectional risk relationship 1
• The presence of psychiatric disorders should be carefully assessed, as they may require separate treatment even when insomnia is present 1

Medical Conditions

• Chronic pain disorders, neurological conditions (Parkinson's disease, stroke, Alzheimer's disease), and endocrine disorders (hypothyroidism) can disrupt sleep maintenance 1, 3
• Sleep-disordered breathing (obstructive sleep apnea affects approximately 24% of older adults) causes sleep fragmentation and early awakening 3
• Restless legs syndrome, particularly with low ferritin levels, can cause nocturnal awakenings 3

Medication and Substance Effects

Common Culprits

• Stimulants (caffeine, methylphenidate, amphetamines), decongestants (pseudoephedrine), antidepressants (SSRIs, venlafaxine), and cardiovascular medications (β-blockers, diuretics) can disrupt sleep maintenance 1
• Alcohol use, despite initial sedation, causes sleep fragmentation and early morning awakening 1
• Narcotic analgesics and pulmonary medications (theophylline, albuterol) are associated with sleep disruption 1

Behavioral and Environmental Factors

Poor Sleep Hygiene

• Irregular sleep schedules, excessive time in bed attempting to "catch up" on sleep, and bedroom activities incompatible with sleep (TV watching, computer use, clock-watching) perpetuate insomnia 1
• The bed becomes conditioned as a place of waking arousal through repeated frustration and "trying hard" to fall asleep 1
• Inadequate evening light exposure, particularly in older adults with cataracts, can perpetuate advanced sleep phase patterns 1

Diagnostic Approach

Essential History Elements

• Document sleep-wake timing for at least 7 days using sleep diary or actigraphy to identify patterns 1
• Assess for daytime consequences: fatigue (more common than sleepiness in chronic insomnia), mood disturbances, cognitive difficulties, and quality of life impairment 1
• Screen for comorbid sleep disorders (sleep apnea with snoring/witnessed apneas, restless legs symptoms), medical conditions, psychiatric disorders, and medication/substance use 1, 3
• Evaluate pre-sleep behaviors, bedroom environment, and daytime activities including napping patterns 1

When to Consider Specific Diagnoses

• If early bedtime (6-9pm) accompanies early awakening, suspect ASPD rather than insomnia 1
• If significant daytime sleepiness (not just fatigue) is present, investigate for sleep apnea, narcolepsy, or other primary sleep disorders 1, 3
• Polysomnography is not routinely indicated for insomnia but should be considered when sleep-disordered breathing or other primary sleep disorders are suspected 1

Treatment Priorities

First-Line Treatment

• Cognitive behavioral therapy for insomnia (CBT-I) is the recommended initial treatment for chronic insomnia disorder, including early morning awakening patterns 1, 4
• CBT-I includes stimulus control, sleep restriction, cognitive therapy, and sleep hygiene education, with durable long-term effects after treatment discontinuation 1, 4

ASPD-Specific Management

• Chronotherapy (advancing sleep times every 2 days until desired schedule is achieved) combined with good sleep hygiene practices 1
• Evening bright light exposure to delay the circadian phase 1

Pharmacological Considerations

• Medication should only be added after CBT-I alone has been unsuccessful, using shared decision-making to discuss benefits, harms, and costs of short-term use 1
• Address any contributing medications or substances identified in the evaluation 1

Critical Pitfalls to Avoid

• Do not assume early morning awakening in older adults is "normal aging"—it warrants thorough evaluation 1, 3
• Do not overlook the possibility that multiple causes coexist, particularly in older adults with comorbidities and polypharmacy 3
• Do not diagnose insomnia when the patient has an advanced sleep phase but no distress or functional impairment (these are "morning types" or "larks," not ASPD) 1
• Do not treat insomnia with medication before attempting CBT-I, as only CBT-I provides durable long-term benefits 1, 4