Definition
Insomnia is difficulty falling asleep, staying asleep, or returning to sleep after an early-morning waking, despite adequate opportunity to sleep. Chronic insomnia is defined as occurring at least three nights per week for at least three months. It's one of the most common features of anxiety and one of its most reliable amplifiers.
What it can feel like
Lying awake with a mind that won't slow down. Falling asleep, then waking at 2 or 3 a.m. unable to settle back. Mornings that feel worse than the night before. A sense of dread about bedtime that builds across the day, which itself makes sleep harder.
Why it happens
Anxiety raises sympathetic tone and cortisol, both of which oppose the physiological state required for sleep. Insomnia and anxiety reinforce each other in both directions: poor sleep increases next-day anxiety, and increased anxiety interferes with the next night's sleep. Cognitive behavioral therapy for insomnia (CBT-I) has the strongest evidence for chronic insomnia and addresses the anxiety component well. Sleep medications can help in the short term but tend not to treat the underlying pattern.
Acute, short-term, and chronic insomnia
A clinically useful distinction. Acute insomnia lasts a few nights and follows an identifiable trigger, a stressful event, jet lag, illness. Short-term insomnia lasts days to a few weeks. Chronic insomnia is sleep difficulty occurring at least three nights a week for three or more months. The treatment differs by category. Acute and short-term insomnia often resolve on their own as the trigger settles; chronic insomnia is what most current treatment guidelines target.
Why CBT for insomnia outperforms medication
Cognitive behavioral therapy for insomnia (CBT-I) is the first-line treatment for chronic insomnia in current guidelines from the American College of Physicians and most professional sleep medicine societies. The reason it outperforms medication over the long term is mechanism. Sleep medication produces sleep tonight; CBT-I retrains the system that has been producing the insomnia.
CBT-I has five components. Sleep restriction temporarily reduces time in bed to consolidate sleep, then expands it as efficiency improves. Stimulus control re-establishes the bed as a cue for sleep. Cognitive restructuring addresses the catastrophic thinking about sleep that maintains the cycle. Sleep hygiene establishes the behavioral baseline, consistent rise time, morning light, evening dim lighting, caffeine limits. Relaxation training reduces pre-sleep arousal.
Most courses run 6 to 8 weeks. Digital CBT-I programs (Sleepio, Somryst, the CBT-I Coach app) provide a reasonable starting point where in-person providers are difficult to find.
When medication has a role
Sleep medication is appropriate for short-term insomnia from a specific identifiable stressor. For chronic insomnia, medication is generally used at the lowest effective dose for the shortest necessary period. Trazodone at 25 to 100 mg is commonly prescribed off-label and has a reasonable side effect profile. Mirtazapine at 7.5 to 15 mg is sedating and can be useful when depression is also present. Z-drugs and benzodiazepines work but carry dependence and cognitive side-effect risks, particularly in older adults. Over-the-counter sleep aids based on diphenhydramine have anticholinergic effects and aren't recommended for ongoing use.
Any decision to start a sleep medication is best made with a clinician who has the full picture.
When to see a clinician
Insomnia that runs three or more nights a week for more than a month is chronic and warrants clinical attention. CBT for insomnia is the first-line treatment and outperforms medication over the long term.