No clinical trial or longitudinal study has proven that gabapentin directly causes Alzheimer’s disease or any form of dementia. That said, the concern is not baseless. Multiple large observational studies have found that long-term gabapentin users develop dementia at noticeably higher rates than matched controls, and a 2025 animal study identified a plausible brain-level mechanism involving tau protein, one of the hallmarks of Alzheimer’s pathology. The real question is whether gabapentin is an independent driver of cognitive decline, or whether the conditions it treats and the people who take it explain most of the statistical signal.
What Large Population Studies Have Found
Two major studies stand out. A nationwide analysis of Taiwan’s health insurance database followed people who were prescribed gabapentin or the closely related drug pregabalin and compared them to matched non-users. After adjusting for age, sex, and other medical conditions, gabapentin or pregabalin users had roughly a 45 percent higher rate of being diagnosed with dementia. The risk climbed with higher cumulative doses, and it was paradoxically most pronounced in younger patients under 50, where the rate was more than three times that of non-users.1PubMed Central. The association between Gabapentin or Pregabalin use and the risk of dementia
A separate study focused specifically on chronic low back pain patients in the United States. It found that those with six or more gabapentin prescriptions had about a 29 percent higher rate of dementia and an 85 percent higher rate of mild cognitive impairment compared to low back pain patients not prescribed the drug. Again, younger adults showed a sharper relative increase, with those aged 18 to 64 seeing about double the dementia rate. And risk continued to climb with more prescriptions: people filling 12 or more had a 40 percent higher dementia rate than those with fewer fills.2PubMed. Risk of dementia following gabapentin prescription in chronic low back pain patients
These numbers look alarming at first glance. But both studies are observational, meaning they tracked what happened to people who were already taking gabapentin versus people who were not. They did not randomly assign the drug, so they cannot prove the drug itself caused the cognitive decline. There are strong reasons to suspect confounding factors are doing a lot of the heavy lifting.
Why the Conditions Behind the Prescription Matter
Gabapentin is most often prescribed for chronic nerve pain, epilepsy, and sometimes anxiety or insomnia. Each of these conditions, especially chronic pain, has its own relationship with dementia risk. A large prospective cohort study found that chronic pain itself appears to be a risk factor for later dementia, and that the risk climbs with the number of pain sites a person reports. The researchers argued this was unlikely to be just early dementia symptoms masquerading as pain complaints, because the association held up even with long follow-up periods.3PubMed Central. Association between chronic pain and risk of incident dementia
This creates a serious interpretation problem called indication bias. People prescribed gabapentin are not a random slice of the population. They are people living with chronic pain, nerve damage, seizures, or other conditions that disrupt sleep, limit physical activity, and produce stress, all of which are independently linked to cognitive decline. When a study finds that gabapentin users develop dementia more often, it may be telling us more about the conditions gabapentin treats than about gabapentin itself.
The dose-response pattern (more prescriptions correlating with more dementia) can look like a smoking gun, but it is also consistent with confounding. People who fill more prescriptions tend to have more severe or persistent conditions, and those conditions may themselves drive cognitive risk upward. Neither study was able to fully untangle the drug effect from the disease effect.
What Animal Research Has Uncovered
Where the observational data leaves room for doubt, recent laboratory work has started to fill in a biological story that is harder to explain away as confounding. A 2025 study in aged mice found that long-term gabapentin treatment impaired short-term recognition memory. Gabapentin-treated mice performed significantly worse at recognizing novel objects compared to saline-treated controls, regardless of whether the mice were also modeling nerve injury. The memory impairment was tied to increased phosphorylation of tau protein in the brain, a molecular hallmark of Alzheimer’s disease.4PubMed Central. Long-term gabapentin treatment impairs cognitive function in aged mice via tau hyperphosphorylation
This matters because tau tangles are one of the two defining features of Alzheimer’s pathology, along with amyloid plaques. If gabapentin promotes tau phosphorylation in aging brains, that would represent a direct biological pathway by which the drug could contribute to neurodegeneration, not just temporary fogginess.
Separately, an influential cell biology study identified the protein that gabapentin binds to in the brain, called alpha2delta-1, as a key receptor for forming new excitatory connections between neurons. Gabapentin blocks a molecule called thrombospondin from binding to this receptor, which powerfully inhibits the formation of new synapses in both cell cultures and living animals.5PubMed Central. Gabapentin receptor alpha2delta-1 is a neuronal thrombospondin receptor responsible for excitatory CNS synaptogenesis Synapse formation is how the brain rewires and adapts, and it plays a role in learning and memory. If gabapentin chronically suppresses this process, particularly in older brains that are already losing synapses, the long-term cognitive consequences could add up even if the short-term effect on any given day feels minor.
These are still animal and cellular findings. They suggest a plausible mechanism but do not prove that the same process is causing dementia in human gabapentin users. The dose, duration, and species differences between mouse experiments and human prescriptions are real caveats. But the findings do move the conversation beyond “it’s probably just confounding” toward a genuine biological concern worth tracking.
Why Older Adults Are Especially Vulnerable
Gabapentin is cleared almost entirely by the kidneys. It is not broken down by the liver the way many drugs are, so its concentration in the blood depends directly on how well your kidneys are working.6Mayo Clinic Proceedings. A 71-Year-Old Man With Altered Mental Status Kidney function declines with age, often without obvious symptoms. A 75-year-old with “normal” blood tests may still have significantly reduced kidney filtration compared to a 40-year-old.
This creates a predictable problem. A study of patients with chronic kidney disease found that gabapentin toxicity occurred exclusively in those with reduced kidney function, and it was most severe in patients with the greatest impairment. Elderly patients with multiple health conditions were overrepresented among those who became toxic.7PubMed. Gabapentin toxicity in patients with chronic kidney disease The toxic effects included confusion, sedation, and altered mental status, symptoms that in an older person could easily be mistaken for emerging dementia rather than drug side effects.8American Society of Nephrology. Gabapentin Toxicity in Existing and Developing Renal Failure
This is worth emphasizing because gabapentin is widely perceived as a “safe” drug, partly because it has fewer liver-related drug interactions than many alternatives. That reputation can lead clinicians to maintain the same dose even as a patient’s kidney function quietly deteriorates over years. The result is drug accumulation that neither doctor nor patient may recognize until cognitive symptoms become obvious.
The Polypharmacy Problem
Gabapentin is rarely the only medication an older adult is taking. A study of gabapentin users enrolled in a national Alzheimer’s research database found that by 2019, roughly 16 percent of gabapentin users with normal cognition were also taking opioids, and up to about 8 percent were taking both opioids and benzodiazepines at the same time.9PubMed Central. Gabapentin utilization among older adults with different cognitive statuses enrolled in the National Alzheimer’s Coordinating Center All three drug classes depress the central nervous system. Stacking them multiplies the sedating and cognition-dulling effects, and older adults metabolize each drug more slowly, so the overlap lasts longer.
When researchers find that gabapentin users develop dementia more often, some portion of that signal may reflect the combined burden of multiple brain-slowing drugs rather than gabapentin alone. The studies described earlier attempted to adjust for other medications, but no statistical adjustment perfectly captures the real-world complexity of an older person taking five or six drugs with overlapping side effects.
Do the Cognitive Effects Reverse After Stopping?
This is one of the most practically important questions for people currently taking gabapentin, and the early evidence is somewhat reassuring. A study comparing gabapentin to another anti-seizure drug in healthy older adults found that both drugs slightly dulled performance on cognitive tests compared to being off medication. Gabapentin performed a bit better than the comparator on attention tasks, but overall, the no-drug condition beat both drugs on the majority of measures. The key finding was that the cognitive effects appeared to be drug-related rather than permanent.10Epilepsia. Comparative cognitive effects of carbamazepine and gabapentin in healthy senior adults
More recently, a preprint study using two large medical databases examined whether cognitive symptoms improved after patients stopped taking gabapentin, specifically when it was being combined with a type of blood pressure medication called a dihydropyridine calcium channel blocker. Cognitive symptom rates were meaningfully higher while patients were on both drugs than after they stopped. The improvement was most pronounced in adults 65 and older.11medRxiv. Do Cognitive Symptoms Improve When Gabapentin and Dihydropyridine Calcium Channel Blocker Therapy Are Stopped? This finding has not yet been published in a peer-reviewed journal, so it should be interpreted cautiously. But it aligns with clinical experience: many patients and their doctors report that the mental fog associated with gabapentin clears within weeks of tapering off.
Reversibility matters because it draws a line between gabapentin acting as a temporary cognitive suppressant and gabapentin causing true neurodegeneration. If stopping the drug restores function, the problem is pharmacological, meaning the drug is affecting brain chemistry while it is present but not destroying brain tissue. That is a very different scenario from triggering Alzheimer’s pathology. The mouse data on tau phosphorylation complicates this picture, though, because tau changes can persist even after the triggering insult is removed.
Adverse Event Signals From Post-Marketing Surveillance
Beyond formal studies, the U.S. FDA maintains a database of adverse event reports submitted by patients, doctors, and manufacturers. An analysis of nearly 2.7 million patient records in this database identified over 15,000 cases classified as drug-induced amnesia. Gabapentin was among the medications associated with elevated odds of amnesia reports, alongside pregabalin, a statin, and another anti-seizure medication.12PubMed. Leveraging Signal Detection and Mendelian Randomization in Spontaneous Reporting for Post-Marketing Surveillance of Drug-Induced Amnesia
Adverse event databases are useful for detecting unexpected patterns, but they have well-known limitations. Reports are voluntary, so they capture only a fraction of actual events. There is no control group, so you cannot calculate a true risk. And the reports do not distinguish between temporary memory lapses while on a drug and lasting cognitive decline. Still, the fact that gabapentin consistently appears in these signals, alongside its biological profile and the observational data, keeps it on the radar as a drug deserving closer scrutiny for cognitive effects.
The Contradictory Role of Gabapentin in Brain Injury
One of the more confusing aspects of this topic is that gabapentin has shown protective effects on the brain in certain experimental settings. In animal models of brain hemorrhage, gabapentin reduced inflammation and tissue damage by dampening a key inflammatory signaling pathway, leading to improved behavioral outcomes in rats.13PubMed. Gabapentin Alleviates Brain Injury in Intracerebral Hemorrhage Through Suppressing Neuroinflammation and Apoptosis In immature mouse brains subjected to reduced blood flow, gabapentin suppressed seizures and reduced brain tissue loss at higher doses.14PubMed Central. Gabapentin neuroprotection and seizure suppression in immature mouse brain ischemia
These findings might seem contradictory, but they likely reflect the difference between acute injury and chronic exposure. In an acute brain injury, calming overexcited neurons and reducing inflammation can save tissue. Over months or years, that same dampening of neural activity and synapse formation could slowly erode cognitive reserve. It is also possible that the dose, timing, and age of the brain matter enormously. A drug that protects a young brain from an acute insult could harm an aging brain during years of continuous use. Biology is full of these dose-and-context reversals.
When Gabapentin Is Used in People Who Already Have Dementia
Adding another layer of complexity, gabapentin is sometimes prescribed to people who already have dementia. Behavioral and psychiatric symptoms of dementia, including agitation, aggression, and anxiety, are common and difficult to manage. Several case reports and a systematic review have explored gabapentin as an off-label treatment for these symptoms, partly because it has anxiety-reducing properties and partly because unrecognized nerve pain may be driving agitation in some patients who cannot verbalize what they are feeling.15The American Journal of Geriatric Psychiatry. Gabapentin for Behavioral and Psychiatric Symptoms of Dementia
No definitive trial has established gabapentin as an effective intervention for these behavioral symptoms, but it continues to be used in clinical practice. This creates an ironic situation: a drug under suspicion for contributing to cognitive decline is simultaneously being given to patients already experiencing it, because the alternatives, often antipsychotics, carry their own serious risks in elderly patients. For clinicians, the calculation is not whether gabapentin is perfectly safe but whether it is safer than the other options available for a distressed patient.
Subjective Fog Versus Measurable Decline
Many gabapentin users report feeling mentally foggy, slow, or forgetful. These complaints are real and deserve to be taken seriously. But research across chronic pain populations has consistently found a large gap between how many people report cognitive difficulties and how many show measurable impairment on standardized testing. In one study of patients within a pain rehabilitation setting, 96 percent reported subjective cognitive complaints, yet as a group they performed in the average range on formal tests of attention, memory, and intellectual functioning. The rate of objectively measured attention weaknesses was around 4 percent, while 93 percent reported subjective attention difficulties.16Journal of Pediatric Psychology. Neurocognitive Difficulties Among Youth with POTS within an Intensive Pain Rehabilitation Program
This does not mean gabapentin users are imagining their symptoms. Fatigue, pain, poor sleep, depression, and the sedating effects of medications can all produce a genuine feeling of cognitive impairment without underlying neurodegeneration. The distinction matters because feeling foggy on a drug is a very different clinical problem from that drug giving you Alzheimer’s. The first can be managed by adjusting the dose, switching medications, or addressing contributing factors. The second would be a reason to avoid the drug entirely in many people.
What Practical Steps Make Sense
If you are taking gabapentin and worried about your cognitive health, the evidence supports a few practical steps rather than panic. First, kidney function should be checked periodically, especially if you are over 60 or have any conditions that can affect the kidneys like diabetes or high blood pressure. Doses that were appropriate five years ago may be too high now if kidney filtration has slipped. Second, review the full list of medications you take with your doctor. The combination of gabapentin with opioids, benzodiazepines, or certain other sedating drugs amplifies cognitive side effects beyond what any single drug would cause.
Third, if you are experiencing new cognitive symptoms and taking gabapentin, a carefully supervised taper is worth discussing with your prescriber. The available evidence suggests that drug-related cognitive effects often improve after stopping. But do not stop gabapentin abruptly, particularly if you take it for seizures, as sudden discontinuation can provoke withdrawal symptoms or seizure recurrence.
Finally, keep perspective on what the science actually shows right now. The observational studies found associations, not proof of causation. The animal data raises a legitimate biological concern about long-term tau changes, but we do not yet know whether human brains at typical doses behave the same way mouse brains do at experimental doses. No medical society has classified gabapentin as a known cause of dementia. For many patients, gabapentin provides meaningful relief from pain or seizures that would otherwise severely impair quality of life, and that benefit has to be weighed against a risk that remains theoretical at the individual level.