Here’s Why Some Patients Change at Sundown (or Even During a Full Moon)
They’re not.
Think of it this way…
Dementia is the umbrella. Alzheimer’s is one of the storms underneath it.
Dementia isn’t actually a disease. It’s a term doctors use to describe a collection of symptoms that affect memory, thinking, judgment, language, and the ability to perform everyday tasks.
Alzheimer’s disease, however, is a specific brain disease—and it’s the most common cause of dementia, accounting for roughly 60–80% of cases. (Mayo Clinic)
But Alzheimer’s isn’t the only one.
There are also:
- Vascular dementia
- Lewy body dementia
- Frontotemporal dementia
- Mixed dementia (when more than one type occurs together)
Each affects the brain differently.
So… What Exactly Is Sundowning?
One of the most heartbreaking things caregivers talk about is something called sundowning.
During the day, a loved one may seem calm and even recognize family members.
Then around late afternoon or early evening…
Everything changes.
They may suddenly become:
• Confused
• Restless
• Anxious
• Angry
• Suspicious
• Agitated
• Start pacing or wandering
• Believe they’re somewhere else
• Ask to “go home” even when they’re already home
Doctors call this sundowning syndrome because these symptoms typically appear around sunset and continue into the evening. (Mayo Clinic)
Why Does It Happen?
Researchers still don’t have one single answer.
But several things appear to play a role.
As daylight fades, the brain has to rely more on its internal clock. In Alzheimer’s disease and other dementias, that internal clock—called the circadian rhythm—often becomes damaged or disrupted.
That means the brain struggles to recognize when it’s time to wind down, rest, or sleep.
Add in fatigue from the day’s activities, darker rooms, unfamiliar shadows, hunger, dehydration, pain, or medication effects, and confusion can become much worse by evening. (PubMed)
But What About the Full Moon?
Now here’s the question that always sparks debate.
Ask almost any nurse, caregiver, or emergency room worker, and many will tell you:
“People seem different during a full moon.”
Science, however, isn’t quite so certain.
Some smaller studies have reported increased wandering, anxiety, aggression, or agitation in people with Alzheimer’s during full moons.
Other well-designed studies found no significant difference at all. (PubMed)
So who’s right?
The honest answer is…
We don’t know yet.
Researchers have suggested a few possibilities:
- Brighter moonlight may disturb sleep.
- Changes in nighttime lighting could increase confusion.
- Some people may simply notice difficult behaviors more because they expect them during a full moon.
- Caregivers may remember unusual nights more vividly than ordinary ones.
At this point, there is no strong scientific consensus proving that the full moon directly causes behavioral changes in dementia patients. The evidence is mixed, and researchers continue to study the question. (PubMed)
What Caregivers Can Do
While we can’t stop dementia, we can sometimes reduce sundowning episodes by:
• Keeping a consistent daily routine.
• Letting in plenty of natural daylight.
• Keeping rooms well-lit before sunset.
• Limiting late-day caffeine.
• Encouraging gentle activity earlier in the day.
• Reducing noise and overstimulation during the evening.
• Making sure pain, hunger, thirst, or bathroom needs aren’t being overlooked. (Mayo Clinic)
Whether it’s sundowning, changes in behavior, or the age-old full moon debate, families often notice patterns long before science has all the answers.
The important thing is to remember this:
Your loved one isn’t trying to be difficult.
Their brain is processing the world differently than yours.
And sometimes, understanding that difference is one of the greatest acts of compassion we can offer.
🖊 A Penny for my thoughts:Sometimes the hardest part of caregiving isn’t the diagnosis—it’s understanding why the person you love seems to become someone else when the sun goes down.
