Why Can't I Sleep? Understanding What's Keeping You Awake

What are the most common reasons you can't fall asleep?

Your body clock is off (circadian misalignment). Your internal clock is programmed to feel sleepy and alert at particular times. If it has shifted — through irregular schedules, late-night light exposure, shift work, or jet lag — your body may simply not be ready for sleep when you lie down 1Ref 1Watson NF, Badr MS, Belenky G, et al. (2015).Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society.Recommended sleep duration for adults (7+ hours); importance of consistent sleep schedule; circadian disruption as a contributor to insomnia. Evening light from screens is a specific and well-documented contributor to this delay 2Ref 2Chang AM, Aeschbach D, Duffy JF, Czeisler CA (2015).Evening Use of Light-Emitting eReaders Negatively Affects Sleep, Circadian Timing, and Next-Morning Alertness.Evening light exposure from screens delays circadian timing and impairs sleep onset.

An anxious or racing mind. Insomnia driven by anxiety or hyperarousal is extremely common. The bedroom can become associated with the effort of trying to sleep and failing — a self-reinforcing cycle. Ordinary work stress, relationship concerns, or even worry about sleep itself can be enough to maintain it. The brain's stress response is fundamentally incompatible with the drop in arousal that sleep requires.

Caffeine. Caffeine blocks adenosine, the chemical that builds sleep pressure throughout the day. Caffeine consumed even six hours before bed meaningfully reduces sleep time 3Ref 3Drake C, Roehrs T, Shambroom J, Roth T (2013).Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed.Caffeine taken even 6 hours before bed reduces total sleep time; recommendation to cut off caffeine by early-to-mid afternoon. Many people underestimate how long it stays active — its half-life in most adults is roughly five to six hours.

Alcohol. Alcohol may help you feel drowsy initially, but it significantly fragments sleep in the second half of the night — often causing waking in the early morning hours and reducing sleep quality overall 4Ref 4Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB (2013).Alcohol and Sleep I: Effects on Normal Sleep.Alcohol initially promotes drowsiness but fragments sleep architecture in the second half of the night.

Irregular schedule. Sleep responds to consistency. Wide variation in wake time — the single most powerful lever for stabilizing the circadian signal — weakens the body's ability to fall asleep reliably 1Ref 1Watson NF, Badr MS, Belenky G, et al. (2015).Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society.Recommended sleep duration for adults (7+ hours); importance of consistent sleep schedule; circadian disruption as a contributor to insomnia.

An underlying sleep or medical condition. Sleep apnea, restless legs syndrome, and periodic limb movement disorder can all make initiating or maintaining sleep difficult. These require clinical evaluation — behavioral changes alone will not resolve them.

What is the difference between insomnia and other sleep problems?

Insomnia specifically means difficulty falling asleep, staying asleep, or waking too early — combined with feeling unrefreshed and having the problem affect daytime functioning — for at least three nights a week over at least three months (chronic insomnia). Shorter episodes are acute insomnia and often resolve on their own.

Other distinct problems that people may confuse with insomnia:

• Delayed sleep phase disorder: You cannot fall asleep until very late (2–4 am) but sleep well once asleep — this is a circadian rhythm disorder, not classic insomnia
• Sleep apnea: You may not know you have it; frequent nighttime awakenings, loud snoring, and unrefreshing sleep are common signs — a sleep study is required to confirm
• Hyperarousal insomnia: You are tired during the day but feel 'wired' at bedtime — very amenable to CBT-I

Mismatching the treatment to the wrong problem is a major reason self-treatment fails.

What actually helps — and the treatment that outperforms sleep medication?

For most adults with chronic insomnia, Cognitive Behavioral Therapy for Insomnia (CBT-I) is the evidence-based first-line treatment 5Ref 5Edinger JD, Arnedt JT, Bertisch SM, et al. (2021).Behavioral and Psychological Treatments for Chronic Insomnia Disorder in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline.CBT-I as first-line evidence-based treatment for chronic insomnia in adults. Multiple systematic reviews have found it outperforms sleep medication for long-term outcomes, with no side effects or dependency risk 6Ref 6Trauer JM, Qian MY, Doyle JS, Rajaratnam SMW, Cunnington D (2015).Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-analysis.CBT-I outperforms sleep medication for long-term insomnia outcomes; meta-analytic evidence for efficacy. CBT-I typically involves sleep restriction, stimulus control, and restructuring the beliefs that perpetuate insomnia. It is available through trained therapists, some primary care practices, and several digital programs.

Behavioral changes that support CBT-I — and help on their own for milder cases:

• Consistent wake time — keep it the same seven days a week, regardless of how little you slept
• Only go to bed when sleepy (not just when it is 'bedtime')
• Get out of bed if you cannot sleep within about 20 minutes — lying awake reinforces the association between bed and wakefulness
• Reduce napping — daytime naps reduce nighttime sleep pressure
• Cut off caffeine by early-to-mid afternoon 3Ref 3Drake C, Roehrs T, Shambroom J, Roth T (2013).Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed.Caffeine taken even 6 hours before bed reduces total sleep time; recommendation to cut off caffeine by early-to-mid afternoon

Sleep medications — prescription and over-the-counter — may have a limited role in acute, short-term insomnia, but are generally not recommended for chronic insomnia and some carry tolerance and dependency risks. A clinician can advise whether a short course makes sense for your situation.

When should you see a clinician — and which one?

See a clinician if:

• Sleep problems have persisted for more than a few weeks and are affecting daily life
• You have tried consistent behavioral changes and they have not helped
• You suspect an underlying condition — anxiety, depression, sleep apnea, or restless legs
• You are relying on alcohol or sleep aids regularly
• A bed partner has noticed loud snoring, gasping, or pauses in breathing

Who to see: Primary care is usually the right first stop — they can screen for underlying conditions, check relevant labs, refer for a sleep study if needed, and often deliver or refer for CBT-I. A behavioral health clinician trained in CBT-I is the right referral when anxiety, hyperarousal, or chronic stress is the primary driver. A sleep medicine specialist handles complex cases, circadian disorders, and confirmed or suspected sleep apnea.