불면은 왜 계속될까Why Insomnia Sticks Around

1. What starts it, and what keeps it going

Insomnia usually starts with something: a move, a new job, a new baby, a breakup, a family member’s illness, a big exam. Often, though, sleep doesn’t come back even after that event has passed.

Sleep researcher Arthur Spielman described this with three factors (Spielman, Caruso, et al., 1987).

• What you came in with: a sensitive nervous system, a tendency to worry, a late “night owl” rhythm, anything that makes sleep easier to unsettle
• What set it off: the stress or change that first disrupted sleep
• What you did to get sleep back: going to bed early, staying in bed late, napping, catching up on weekends

The third factor matters most. The things we do to recover sleep often end up holding insomnia in place. Going to bed early after a bad night makes sense, but it adds time lying awake in bed and ties the bed more tightly to the experience of not sleeping.

That’s why sleep can stay broken after the original problem is solved. Weak willpower has nothing to do with it. By now, insomnia is more likely being maintained by current habits and what your body has learned. Habits and learning can change.

2. The two forces that make sleep

Sleep comes most easily when two forces line up (Borbély, 1982).

First, building sleepiness. The longer you’re awake, the more sleepiness builds. Researchers call this sleep pressure. Naps and long mornings in bed let that pressure leak out early, leaving less to carry you into sleep at night.

Second, your internal clock. Your body runs on a roughly 24-hour rhythm called the circadian rhythm. The strongest signal for setting that clock is light, especially morning light. Getting up at the same time every day fixes when you get that light, which steadies the clock. When wake times shift day to day, your body loses track of when to feel sleepy.

Most of the behavioral work in CBT-I is about getting these two forces back in sync. Parts 03 and 04 cover how.

3. When your body is still on night watch

Some nights you’re plenty sleepy and still can’t fall asleep. That’s when your body has decided it isn’t safe to rest yet.

People with long-standing insomnia tend to have a nervous system that runs “on” both day and night. This is called hyperarousal (Riemann et al., 2010): a slightly faster heartbeat, thoughts that won’t switch off, waking at small sounds.

Hyperarousal isn’t a personality flaw. It’s closer to a state where alertness, raised by stress or long-term poor sleep, hasn’t come back down yet. Part 05 covers ways to lower it gradually.

4. Why effort pushes sleep away

Sleep is one of the few things in life you can’t get by working harder. The more you try to fall asleep, the more your attention locks onto sleep, and that attention raises arousal. Colin Espie and colleagues described this as the attention–intention–effort pathway (Espie et al., 2006).

Thoughts like “I have to sleep tonight” or “If I fall asleep now, I’ll still get five hours” are completely natural. They also turn the bed into a test. Part 06 looks at other ways to relate to these thoughts.

5. What CBT-I changes

About the evidence. That CBT-I works is fairly well established. In a meta-analysis, compared with control conditions, CBT-I reduced the time it took to fall asleep by about 19 minutes on average and time awake during the night by about 26 minutes, and improved sleep efficiency by about 10 percentage points (Trauer et al., 2015). Total sleep time, however, didn’t increase much right after treatment. In other words, sleep tends to become more continuous and better quality before it becomes longer.

The American College of Physicians recommends CBT-I as the first treatment for chronic insomnia (Qaseem et al., 2016), and the American Academy of Sleep Medicine strongly recommends it (Edinger et al., 2021).

Exactly how each component works, and which matters most for whom, is still being studied. So at PADO, we use your diary to find the combination that fits you.

6. Limits of this explanation

• This page focuses on insomnia disorder. Other sleep conditions, such as sleep apnea, restless legs syndrome, or circadian rhythm sleep disorders, need different evaluation and treatment.
• In ADHD, the internal clock is often set late; in autism, rhythms are often irregular. Both groups have high rates of insomnia. There’s still little research on adapting CBT-I for neurodivergent people, so the adaptations in this series are clinical suggestions based on general principles.
• CBT-I can help when insomnia comes with depression, anxiety, or trauma. The pace and order are best decided with your therapist.