An Intro to Sleep Issues: Insight into clinical thinking
Three-System Insomnia Workup
Insomnia is a symptom, not a diagnosis. Three systems have to work together for sleep to happen. When we understand which one is off, or which combination, treatment stops being guesswork and starts being precise.
Timing
The clock is shifted relative to the desired schedule. Not an inability to sleep, a timing mismatch wearing an insomnia costume.
- "With no alarm or obligations, when does your body actually want to sleep and wake?"
- Weekday vs. weekend gap in bed/wake times?
Pressure
Not enough homeostatic pressure (adenosine) at bedtime. Too much time in bed dilutes it across the night.
- "Time in bed vs. time actually asleep?"
- Naps? Daytime movement? Going to bed early to "catch up"?
Nervous system too hot
Physiological + cortical + cognitive-emotional over-activation that overrides C and S. The trait that turns a bad week into chronic insomnia.
- "In bed, is your body calm or wired? Mind racing?"
- "If you're exhausted midday, can you nap?" (often no = trait arousal)
Before we add calming practices: why is this system activated?
Arousal is often secondary. If something is driving it, calming work alone won't be enough. We treat the driver.
Heuristic: no amount of slow breathing fixes an untreated apnea, an iron deficiency, or 200 mg of caffeine at 3pm.
What we tune each system with
These aren't separate from the three systems, they're the inputs that run them. Addressing them is part of working on C, S, or H, not a fourth thing on the list.
- Light is the primary input to the circadian clock
- Movement is the primary input to sleep pressure
- Daytime nervous system load and regulation directly sets the arousal baseline
- Meal timing and substances touch all three
Differential Diagnoses of Sleep Complaints
Difficulty falling asleep
| Diagnosis | Clinical clues |
|---|---|
| Poor sleep hygiene | Caffeine, alcohol, or nicotine too late; screens and light near bedtime; irregular schedule; exercising too close to bed. Clear this first, since it confounds everything downstream. |
| Circadian delay (DSWPD) | Can't fall asleep until very late but sleeps normally once asleep if allowed to wake late. Common in younger adults and night owls. Look for a stable delay, not a variable one. |
| Psychophysiological insomnia / conditioned hyperarousal | Bed has become a cue for wakefulness. Sleeps better away from home (couch, hotel). Racing mind, clock-watching, effort to sleep that backfires. |
| Anxiety / GAD | Cognitive arousal at sleep onset: worry, rumination, can't shut the mind off. Often the bridge symptom between insomnia and a mood/anxiety disorder. |
| Restless legs syndrome (RLS) | Urge to move legs, worse at rest and in the evening, relieved by movement. Frequently missed. Ask directly. Check ferritin (target >75-100). |
| Substance / medication effect | Stimulants, activating antidepressants (bupropion, SSRIs dosed late), steroids, decongestants, theophylline, beta-agonists. Review timing as well as the drug. |
| Pain / medical discomfort | Chronic pain, GERD, dyspnea, pruritus, nocturia. Sleep onset suffers when lying down worsens the symptom. |
| Mania / hypomania don't miss | Decreased need for sleep (feels rested on little) rather than distressed insomnia. A different animal: screen for it, don't sedate into it. |
Difficulty staying asleep
| Diagnosis | Clinical clues |
|---|---|
| Obstructive sleep apnea don't miss | Snoring, witnessed apneas, gasping, fragmented sleep, morning headache, unrefreshing sleep, daytime sleepiness. Screen with STOP-BANG and refer for study. The single most important not-to-miss in maintenance insomnia. |
| Periodic limb movement disorder (PLMD) | Repetitive limb movements fragmenting sleep, often unknown to the patient. Bed partner reports kicking. Overlaps with RLS. |
| Depression don't miss | Classic early-morning awakening with inability to return to sleep, plus anhedonia, low mood, diurnal variation. Maintenance insomnia is a depression flag until proven otherwise. |
| Nocturia | Waking to urinate. BPH, diuretics (and their timing), fluid load, OSA itself (raises ANP). Easy to overlook as 'just getting older.' |
| Alcohol | Sedates at onset, then fragments the back half of the night as it metabolizes and arousal rebounds. Ask about the nightly drink that "helps me sleep." |
| Pain / medical | Pain, dyspnea, GERD, asthma, COPD, heart failure (orthopnea, PND), hot flashes. Anything that worsens when supine or in the second half of the night. |
| Medication effect | Beta-blockers, diuretics (timing), corticosteroids, stimulants wearing off causing rebound, late-day caffeine. Reconcile the full list. |
| Parasomnias / nightmares | PTSD-related nightmares, REM behavior disorder (acting out dreams, refer), night terrors. The awakening has a specific character worth asking about. RBD is an early Parkinson/Lewy marker. |
| Conditioned arousal (maintenance type) | Wakes, then can't return to sleep because effort and clock-watching re-arouse. Same mechanism as onset insomnia, different timing. |
Early-morning waking
| Diagnosis | Clinical clues |
|---|---|
| Depression don't miss | Prototypical pattern: waking 2-3 hours before alarm, unable to return to sleep, often with worst mood in the morning. Treat the depression, not just the sleep. |
| Advanced sleep phase (ASWPD) | Falls asleep early, wakes early, feels rested. A phase shift, not a deficit. More common in older adults. Distinguish from depression by the absence of distress and the presence of early sleep onset. |
| Age-related sleep change | Normal aging advances phase and reduces slow-wave sleep. Reassurance and circadian strategies before hypnotics. |
| Alcohol / substance | Rebound arousal in the early morning hours as sedative effect clears. |
| Environmental | Early light, noise, partner's schedule, pets. Cheap to fix, easy to miss if you don't ask. |
| Anxiety | Early-morning cortisol rise meeting an already-aroused system; rumination on waking. |
Daytime sleepiness
| Diagnosis | Clinical clues |
|---|---|
| Insufficient sleep (behavioral) | The most common cause by far: not enough time in bed. Quantify total sleep time before reaching for anything exotic. |
| Obstructive sleep apnea | Unrefreshing sleep despite adequate time in bed. Epworth elevated. OSA cluster (snoring, witnessed apneas, morning headache). |
| Narcolepsy don't miss | Excessive sleepiness with cataplexy, sleep paralysis, hypnagogic hallucinations, or sleep-onset REM. Refer for MSLT. Rare but consequential to miss. |
| Idiopathic hypersomnia | Long, unrefreshing sleep with sleep drunkenness on waking, no cataplexy. Diagnosis of exclusion. |
| Circadian misalignment | Shift work, jet lag, or a phase disorder leaving the patient awake against their internal clock. |
| Medication / substance | Sedating medications, residual hypnotic effect, withdrawal states. |
| Depression / atypical depression | Hypersomnia rather than insomnia, especially atypical and bipolar depression. |
| Medical | Hypothyroidism, anemia, chronic fatigue, post-infectious states, B12 deficiency. |
VITAMINS-ABCDEK
A completeness check once the symptom tables are done. Meant to catch the rarer cause, not to organize the workup. Run down the letters and ask whether anything fits before closing.
How sleep works, and the three places it gets stuck
Most of the time, insomnia isn't one problem. It's three systems that have to agree with each other, and when one of them is off, you end up lying there wide awake wondering what's wrong with you. (Usually nothing is wrong with you. Something is just out of sync.) Here are the three, in plain terms, and where each one tends to get stuck.
Timing
Some people aren't bad at sleeping. They're trying to sleep at the wrong time for their particular body. If you're a night owl whose system doesn't really wind down until 1am, lying in bed at 10 with your mind churning isn't a willpower failure. Your body isn't at the door yet (your internal clock runs late, so the sleep window opens late).
The fix here has nothing to do with trying harder. It's light and timing:
- Bright outdoor light in the morning (indoor light is a tiny fraction of the intensity your clock needs)
- Dimmer evenings
- A consistent wake time, including weekends
Over a couple of weeks, that nudges the clock back toward where you want it.
The hunger for sleep
This one works like appetite. The longer you're awake and moving, the more pressure builds up to sleep, the same way skipping the afternoon snack makes you genuinely hungry for dinner. So a lot of what people do when they can't sleep tends to backfire: going to bed earlier, lying in bed longer, napping to make up for a rough night. That's snacking before dinner. You spread a small amount of sleepiness across too many hours in bed, and it goes thin and broken.
The counterintuitive move: spend less time in bed, not more, and move your body during the day so the pressure has somewhere to build.
Arousal
This is the one I see most, and it may be the most maddening, because you're exhausted all day and then the second your head hits the pillow your brain flips on like someone threw a switch. Planning, replaying the day, doing math on how many hours you have left. (A tell: if you're wiped at 3pm but still can't fall asleep for a nap, it's often this. A wired system can't nap either.)
The hard part is that effort makes it worse. Sleep is one of the few things where trying harder backfires, because trying is its own kind of alertness. So a lot of the work is sideways: building small pockets of calm into the day so your nervous system remembers how to downshift.
- A walk without the phone
- A few slow breaths where the exhale is longer than the inhale
- A lunch where you're not also answering email
And at night: getting out of bed when you're wired, instead of lying there teaching your brain that bed is the place where you stare at the ceiling.
One more thing worth naming
The daytime calming work helps, and I want to be clear about what it does: it supports your nervous system. It doesn't force sleep, and nothing really does. Sleep opens when the conditions are right, not when you try harder.
And sometimes that wired-at-night feeling is being driven by something physical that no amount of breathing can touch. Worth knowing what these look like:
- Untreated sleep apnea. The brain keeps pulling you out of deep sleep all night without you knowing.
- Pain.
- Caffeine. It doesn't have to keep you "awake" to lighten sleep and raise your baseline arousal, and timing matters as much as amount.
- Alcohol. Sedating at first, but as it clears your system in the second half of the night, it causes fragmented waking.
- Nicotine and vaping. A stimulant. Withdrawal during the night (especially with heavy use) causes arousal and early waking.
- THC and cannabis. Sedating acutely, but it suppresses REM sleep. On cessation or tolerance breaks, rebound hyperarousal and vivid dreaming are common.
- Low iron, thyroid issues, perimenopause.
- A medication you're already taking. Stimulants, some antidepressants, steroids, decongestants.
When there's a cause underneath, we find it and treat that first.
When to come in rather than tough it out: if this has gone on more than a few months, if you snore loudly or someone has noticed you stop breathing in your sleep, or if you're nodding off while driving. And for ongoing insomnia, the most effective treatment isn't a pill, it's a structured approach called CBT-I. Worth asking about.
Most people are some mix of the three. If you can feel which one sounds most like you, that's the place we start.