Insomnia Disorder

Insomnia Disorder

Reviewed by Reja Batool

Insomnia disorder is the point at which bad nights stop being bad nights and become a recognised condition. The DSM-5, the American diagnostic manual clinicians work from, describes it as dissatisfaction with sleep, with trouble falling asleep, trouble staying asleep, or waking too early and not getting back off, despite having a proper chance to sleep, and with real consequences for how the day goes. Two numbers do the work: at least three nights a week, and going on for at least three months.

What it is

The threshold exists to separate two things that feel the same from the inside. One rough fortnight after a hard conversation is not this. Three nights a week since the spring is worth taking to a GP. That is the whole use of a diagnostic criterion in a consumer article: it turns a vague worry into a concrete reason to ask somebody qualified, and it gives a person a sentence to say when they get there.

It is worth being clear about what kind of statement a criterion is. It is a professional consensus document, not a research finding. A committee decided where to draw the line, the line moves between editions of the manual, and the edition should always be named. That is why this page carries the grade not-a-research-claim: there is no study behind the three and the three, there is an agreement.

In effect

When to talk to somebody, beyond the sleep itself

General clinical guidance lists several things that warrant a conversation with a professional rather than with a website: insomnia that persists, panic symptoms, being unable to concentrate at work or in study, sadness that is marked and does not lift, withdrawing from things you normally do, using alcohol or drugs to get to sleep or to cope, and any thoughts of harming yourself. That list is not a checklist to score. It is a set of reasons to make an appointment.

The confusions that are easy to make and worth avoiding

Waking very early is a recognised feature of depression as well as a presentation of insomnia. It is a symptom pattern rather than a mechanism, and it explains nothing on its own.

Sleeplessness plus worry is not an anxiety diagnosis. Generalised anxiety disorder, in the same manual, includes sleep disturbance among its associated symptoms, which means the overlap runs the other way too. Somebody lying awake worrying has a common experience, not a diagnosis.

What happens after the threshold, in one line

If the pattern is there, the treatment guidelines point first at cognitive behavioural therapy for insomnia, ahead of medication. That is a clinician-delivered course, and knowing it exists is a useful thing to bring to the appointment.

What it does not say

It does not tell you what you have. Nothing on this page licenses the sentence "you may have insomnia disorder". Criteria are a prompt to talk to somebody, and this site handles them the same way it handles every other diagnostic threshold it carries.

It is not a research finding. It is a consensus document produced by a committee, it changes between editions, and the edition is named for that reason.

It does not describe severity. Meeting the frequency and duration pattern says nothing about how bad any individual person's nights are, or what is causing them.

It does not distinguish causes. Insomnia that comes with pain, with shift work, with a new medication or with depression all look the same against this criterion, and telling them apart is the clinician's job, not the threshold's.

It is not a reason to stop or start any treatment. Anyone recognising themselves here should be taking that to a GP, not to a webpage.

Sources

  1. DSM-5 criteria for insomnia disorder. Frequency at least three nights a week, duration at least three months, with adequate opportunity for sleep, and with distress or impairment.
  2. DSM-5 criteria for generalised anxiety disorder. Excessive worry more days than not for six months or more, difficult to control, with associated symptoms including sleep disturbance. Recorded here because the overlap is the source of a common confusion.
  3. General clinical guidance on when to seek help, as listed above.
  4. Vault verification record, 2026-09-11. Evidence status not-a-research-claim, because diagnostic criteria are a professional consensus rather than a finding.
  5. Where this came from
  6. No book in this library is the source of this concept. It entered the vault from Why You Lie Awake at 3am, built from primary sources rather than from a book.