Ask someone what bothers them most in the year after a concussion and the answer is often not the headaches. It is the nights. You are exhausted by eight in the evening, asleep by nine, awake at one, and then staring at the ceiling doing arithmetic about how many hours are left. Or it runs the other way: you lie there wired, body tired and brain running, and the first real sleep arrives around the time the alarm is set. Either pattern wears a person down in a way that is hard to describe to anyone who has not lived in it.
Sleep trouble is a recognized part of the picture after a head injury, not a character flaw and not a sign that you are handling things badly. Disrupted sleep sits on the symptom list kept by NINDS, the federal neurology institute at the National Institutes of Health, on its public page on brain injury and concussion, right beside headache, irritability, and trouble holding attention. Naming it matters, because a symptom with a name gets discussed at appointments, and an unnamed one gets absorbed into a vague report that you are tired a lot.
Why the nights change
There is no single mechanism, and anyone who tells you otherwise is simplifying. Some of it is timing: the internal clock that decides when you feel sleepy can drift after an injury, so your body starts asking for bed in the late afternoon and then wakes early with nothing left to do. Some of it is pain, which does not have to be severe to keep pulling you to the surface. Some of it is breathing, which is why sleep apnea is worth asking about even in people who do not fit the picture they expect. And some of it is simply noise and light tolerance, so that the bedroom you slept fine in for a decade is now too bright, too loud, and too warm.
Behavior stacks on top of all of that. After a few bad months most people have built a set of reasonable looking adaptations: the long nap that takes the edge off at four in the afternoon, the two beers that make the ceiling staring stop, the phone at two in the morning because lying in the dark is worse. Each one makes that night slightly easier and the next four nights slightly harder. This is not a failure of willpower, it is what anyone does when sleep becomes unpredictable.
Why it complicates care for low mood
Short, broken sleep produces a great deal of what gets counted as depression. Blunted mood, a short fuse, no appetite or too much of it, slowed thinking, no interest in plans you used to enjoy, a dull sense that nothing is coming. Those are also the things a clinician is scoring when they hand you a questionnaire. So the conversation can go in circles: the mood looks worse than the sleep story suggests, or the sleep complaint gets treated as a symptom of the mood and nothing else.
It complicates the medication side too. Several antidepressants are sedating, several are activating, and which one you land on changes the shape of your nights. A drug that reliably helps people get to sleep is not much use if your actual problem is waking at one and staying up. Sleeping medication can buy a few weeks but tends to lose ground, and some of it leaves you groggy into the morning, which then reads as the low mood getting worse. None of this means medication is the wrong road. It means the sleep pattern has to be described in enough detail that the person prescribing can aim at the right thing.
There is one more reason to be precise. Clinicians use the phrase treatment resistant for depression that holds out against the standard medication sequence, and a past blow to the head is one of the things that raises the odds of ending up there. That is a risk factor and a reason for a closer look at the whole case. That history still does not put anyone in line for ketamine or esketamine, since no single event in a chart decides which treatment a person should receive. Writing the sequence of events down on paper before you go in is worth the effort, and Brain Recovery Centers hosts a page about the months following a crash listing the questions worth settling ahead of time.
What to bring to the next appointment
Two weeks of plain notes beat any amount of description from memory. Each morning write four things: the time you got into bed, roughly when you think you fell asleep, the times you remember waking, and the time you gave up and got up. Add one word for how the day went. Do not grade yourself and do not tidy the numbers. A phone note or the back of an envelope is fine.
Write down the workarounds too, honestly, including the naps and the alcohol and the late scrolling. A clinician is not going to scold you, and leaving those out removes the most useful information in the file. Then mention the injury in the same breath as the sleep, with the date if you have it. If snoring, gasping, or stopped breathing has been reported by anyone who shares a bed with you, say that in the first minute of the appointment rather than the last.
The point of all this is modest. You are not trying to solve the nights in one visit. You are trying to make sure the person deciding what comes next can see the sleep problem clearly, separate from the mood problem it has been feeding, because when the two get collapsed into one complaint the plan that follows is usually aimed at the wrong target.