Plain-language definitions grounded in the clinical and regulatory literature.
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Sleep Disorder
What it isDifficulty falling asleep, staying asleep, or waking earlier than intended, with daytime consequences, occurring at least three nights a week for three or more months.
Why it mattersChronic insomnia affects 10-15 percent of adults. It increases risk of depression, hypertension, cardiovascular disease, and accidents. Cognitive behavioral therapy for insomnia (CBT-I) is the recommended first-line treatment.
Think of it like thisThink of insomnia as the body’s sleep machinery getting locked into the on position by stress, conditioning, or circadian misalignment. Sleeping pills knock you out, but they don’t unlock the machinery, that’s what CBT-I does.
A sleep-wake disorder defined by DSM-5 and ICSD-3 criteria as dissatisfaction with sleep quantity or quality, with one or more of: difficulty initiating sleep, difficulty maintaining sleep, or early-morning awakening, occurring at least three nights per week for at least three months, with associated daytime impairment.
MechanismChronic insomnia involves hyperarousal across cognitive, physiological, and cortical dimensions. Conditioning to the bed and bedroom as cues for wakefulness rather than sleep maintains the disorder. The two-process model frames insomnia as a failure of homeostatic sleep pressure to overcome arousal.
Scientific ConsensusCBT-I is the recommended first-line treatment for chronic insomnia (American College of Physicians, AASM). Pharmacotherapy may be added for short-term use when CBT-I alone is insufficient. Insomnia increases risk of depression, hypertension, and cardiometabolic disease.
Active DebateThe optimal approach for insomnia comorbid with chronic pain, depression, or PTSD. The role of benzodiazepine receptor agonists vs orexin antagonists vs melatonin agonists for chronic pharmacotherapy. Whether digital CBT-I delivers comparable outcomes to in-person treatment.
Emerging ResearchDigital CBT-I platforms expanding access. Orexin receptor antagonists (suvorexant, lemborexant, daridorexant) as alternatives to benzodiazepine receptor agonists with potentially better safety profiles. Personalized chronotype-aligned interventions and circadian phase-shifting protocols.
Key ResearchSpielman 3P model frames chronic insomnia development. Morin and colleagues established CBT-I efficacy across multiple trials. The American College of Physicians (Qaseem et al., 2016) issued the canonical guideline establishing CBT-I as first-line treatment.
— ACP guideline establishing CBT-I as first-line treatment for chronic insomnia
— Modern review of orexin receptor antagonists as insomnia pharmacotherapy
Sleep disorders, PTSD, and the invisible wounds of service can feel isolating. If you or someone you know is in crisis or experiencing thoughts of self-harm, help is available right now. The Veterans Crisis Line provides free, confidential support 24 hours a day, 7 days a week to veterans, service members, and their families.
If you are in crisis or experiencing thoughts of self-harm, call the Veterans Crisis Line at