Dementia is a broad term encompassing the progressive decline of cognitive abilities, such as memory and thinking skills, that severely interfere with daily life. Headaches are one of the most common forms of pain experienced by people worldwide. The question of whether the cognitive changes of dementia can directly cause headaches is complex, and the answer involves looking beyond the cognitive disease itself to shared risk factors, underlying neurological conditions, and indirect effects.
Headaches and Dementia: Clarifying the Causal Link
The cognitive changes defining dementia, such as memory loss, do not directly trigger primary headaches like migraines or tension-type headaches, which are disorders themselves. However, research consistently shows a strong association between a history of primary headache disorders and an increased risk of developing dementia later in life.
This link is often viewed as a shared vulnerability, where common biological mechanisms, such as inflammation, vascular dysfunction, and altered brain chemistry, contribute to both conditions. A history of recurrent headaches, particularly migraines, may be an independent predictor for subsequent dementia risk.
In a person with an established dementia diagnosis, a headache is generally categorized as a secondary headache, meaning it results from another medical condition or external factor. This distinction is crucial because treating the headache requires identifying and managing the separate underlying cause, rather than attributing it directly to the brain atrophy seen in Alzheimer’s disease.
Underlying Medical Conditions That Present Both Symptoms
Many neurological conditions cause both cognitive decline and headaches due to structural or systemic changes in the brain. Recognizing these is vital because some of these conditions are treatable and may lead to a reversible form of dementia.
Vascular dementia, the second most common form, results from impaired blood flow that damages brain tissue, and this vascular pathology often causes headaches. Silent strokes or chronic small vessel disease, hallmarks of this condition, cause both cognitive impairment and vascular headaches. The resulting damage affects brain regions responsible for thinking speed and executive function, often before significant memory loss occurs.
A chronic subdural hematoma (cSDH), a space-occupying lesion, is an important cause because it is often reversible. This condition involves a slow accumulation of blood beneath the outer membrane of the brain, mimicking dementia symptoms like memory impairment and confusion. Headaches are a common complaint in up to 80% of cSDH patients.
Normal Pressure Hydrocephalus (NPH) is another critical example where cerebrospinal fluid buildup enlarges the brain’s ventricles. NPH presents with a classic triad: difficulty walking, urinary incontinence, and progressive cognitive decline. While headaches are not always present, the associated brain swelling can occasionally cause head pain, nausea, and difficulty concentrating.
Indirect Factors Contributing to Headaches in Dementia Patients
Various indirect factors common in the lives of people with dementia can trigger headaches, including medication side effects. Many drugs used to manage dementia symptoms, such as cholinesterase inhibitors (e.g., donepezil) and memantine, list headaches as a potential side effect.
Newer anti-amyloid therapies for Alzheimer’s disease, like lecanemab and donanemab, carry a risk of serious side effects called Amyloid-Related Imaging Abnormalities (ARIA). ARIA involves brain swelling or small bleeds and can manifest with symptoms like headache, confusion, and dizziness. Caregivers should be aware of this potential for medication-induced headaches, especially when starting a new treatment.
Simple physical factors also frequently contribute to headaches. Cognitive decline often leads to difficulty communicating needs, resulting in inadequate fluid intake and subsequent dehydration, a known headache trigger. Furthermore, sleep disturbances, which are highly prevalent in dementia, are strongly associated with headache development. Insomnia and conditions like sleep apnea can cause excessive daytime sleepiness and headaches upon waking.
Recognizing Urgent Warning Signs
The onset of a new headache or a sudden change in a pre-existing pattern in an older adult is a “red flag” requiring immediate medical evaluation. Since a person with dementia may struggle to accurately describe pain, recognizing these warning signs is crucial.
A “thunderclap” headache, which reaches maximum intensity in less than a minute, requires emergency investigation to rule out severe issues like a subarachnoid hemorrhage. Prompt medical attention is also necessary if the headache is accompanied by other urgent symptoms:
- Fever or neck stiffness.
- New neurological deficits, such as weakness, vision changes, or difficulty walking.
- Progressively worsening pain.
- Waking the person from sleep.
- Positional pain (worse when lying down).