Which medications can increase the risk of dementia?

Dementia is a common problem affecting more than 55 million people worldwide.^[1] Its effects on functioning are well known, but no cure has been found. However, it is known that some medications can make dementia more likely to occur and be more severe.

What is dementia?

The simplest definition of dementia is a gradual decline in mental functioning. Memory loss is the most well-known symptom of dementia, but it’s also associated with many other symptoms, including:

• Communication difficulties
• Reduced capacity for problem-solving and critical reasoning
• Inability to complete complex tasks
• Personality changes
• Loss of motor control

Alzheimer’s disease is the most common type of dementia and is treatable with medications, though these medications don’t offer a cure. Other common types of dementia include vascular dementia, Lewy body dementia, and frontotemporal dementia.  

Which types of medication are linked to an increased risk of dementia?

Unfortunately, the list of drugs linked to dementia is rather long. Some, like anticholinergics and benzodiazepines, are more commonly associated with increased dementia risk.^[2] As outlined below, there are many other dementia medications to avoid.

Anticholinergics

Anticholinergic drugs like darifenacin, solifenacin, and trospium treat overactive bladder and incontinence. They do so by blocking acetylcholine, a neurotransmitter responsible for contracting the muscles that control the urine flow.

However, acetylcholine also works in the brain and is associated with learning and memory tasks. Taking anticholinergics blocks acetylcholine’s actions in the brain, leading to memory loss, especially if the drug is taken for an extended period or with other anticholinergic medications.^[3]

Benzodiazepines

Benzodiazepines are anti-anxiety drugs that treat various disorders, from anxiety to delirium to insomnia. Popular options include alprazolam, diazepam, and clonazepam. Each of these drugs increases the effect of GABA, a neurotransmitter that has inhibitory effects on neuronal cells. As a result, patients experience a calming effect that can help reduce anxiety.

But benzodiazepines also reduce brain activity, including in the areas responsible for moving short-term memories to long-term memory. Because of this, they should only rarely be prescribed for people over 65 and should only be used for a short period.

The risk of benzodiazepine use in older adults is that it takes much longer to flush the drug from the system. The buildup of the drug in the body can lead to an array of physical and psychological symptoms, including delirium, motor control issues, and dependency, in addition to concerns about memory impairment.^[4]

Narcotics

Narcotics like fentanyl, hydrocodone, and oxycodone are used to treat pain. In addition to being highly habit-forming, narcotics can also negatively affect a patient’s capacity for short-term and long-term memory. Researchers have also found a potential link between dementia and opioid use in older adults.^[4]

Anticonvulsants

Dementia medications to avoid also include anticonvulsants. Though this medication was developed to treat seizures, they have long been used to treat various conditions, including mood disorders, bipolar disorder, and mania. Common examples include carbamazepine, valproic acid, and gabapentin.

It’s believed that anticonvulsants reduce seizures by decreasing neuronal activity in the central nervous symptoms. The potential risk is that this action can also cause memory loss.^[4] In fact, a 2018 study found that some anticonvulsants increase the risk of Alzheimer’s by up to 30 percent.^[5]

Sedatives

Sedatives like eszopiclone, zolpidem, and zaleplon are prescribed to treat various sleep disorders, like insomnia. In some cases, they may also be prescribed to treat mild anxiety.

The primary risk of some sedatives is that they can cause amnesia. In some cases, patients engage in highly complex behaviors (e.g., driving a car) while on a sedative with no memory of the event once they wake up.^[4] Moreover, previous studies indicate that there is a higher risk of Alzheimer’s among people over 50 who take sedatives compared to people who do not take sedatives.^[6]

Other Dementia Medications to Avoid

Some studies indicate that antidepressants, specifically tricyclic antidepressants like clomipramine, desipramine, and protriptyline, can contribute to memory problems. For example, tricyclics block the action of several neurotransmitters, including serotonin and norepinephrine. As a result, patients – especially older ones – might experience memory lapses, clouded thinking, and confusion.^[4]

Some antihistamines – particularly first-generation drugs like diphenhydramine – have a similar effect on older people.^[4] The adverse effects on memory effectiveness are significant enough that the American Geriatrics Society lists antihistamine drugs as one of several inappropriate medications for older adults.^[7]

Older people with arthritis might have a higher risk of dementia if they take corticosteroids, especially if the dosage is high. In large amounts, steroids can cause memory loss and confusion. Likewise, some patients taking steroids develop depression.^[4] Some studies have indicated that “steroid dementia” might even be an underrecognized issue among older adults.^[8]

Lastly, limited research points to a potential connection between dementia and some antipsychotic medications,^[9] heartburn medications,^[4] and cannabinoids.^[4]

Across the board, certain risk factors make these medications more likely to cause or worsen dementia symptoms. These include the following:^[10]

• Being over the age of 65
• Having a brain injury
• Having a pre-existing form of dementia
• Having mental or physical health conditions that require medication

How to spot the signs of medicine-induced dementia

Dementia can be difficult to diagnose, especially in its early stages, with mild symptoms.^[11] That being the case, it can also be difficult to diagnose dementia induced by medication. However, there are some tell-tale signs to look out for that might point to dementia caused by medications.

The most common symptom of medicine-induced dementia is confusion and a lack of understanding of what’s happening in the immediate situation. These symptoms can be exacerbated by memory disturbances, difficulty generating abstract thoughts, and hallucinations.

Furthermore, medicine-induced dementia often includes lethargy and fatigue, disorientation, and depression – all characteristic symptoms of Alzheimer’s and other forms of dementia.^[10]

The question is, how do you tell the difference between medicine-induced dementia and naturally occurring dementias?

Perhaps the clearest sign that dementia-like symptoms are related to medication is if the symptoms appear quickly after a new medication is taken or an increase in dosage occurs. The changes could be obvious if the person displayed no such symptoms of dementia before the change in medication.

However, detecting medicine-induced dementia isn’t always this easy. In many cases, a patient might already have dementia symptoms, which can be worsened by the medications discussed earlier.

Mental health and medical professionals can take precautions, though, when prescribing new drug treatments. For example, a thorough examination of past, current, and prospective medications can be done to minimize potential interactions. Additionally, medical providers can prescribe alternative treatments or medications in lieu of medications known to increase the risk of dementia.^[10]

It’s also important for mental health and medical providers to conduct a cognitive assessment of the patient before new medications are prescribed or current dosages are increased. Doing so helps establish a baseline if cognitive impairment develops and might help clinicians identify the medication as a possible cause of the patient’s cognitive decline.^[2]

Of course, as noted earlier, it’s imperative to understand what medications make dementia worse in the first place. Understanding what medications to avoid can help minimize the chances of medicine-induced dementia developing in the first place.

Treatment options

The good news is that medicine-induced dementia is one of the most preventable forms of cognitive impairment. Moreover, its potential effects are often reversible.^[12]

But, as noted earlier, the difficulty lies in properly diagnosing the condition. Dementia varies widely in its symptomatology from one type to the next, and patients can also experience differing symptoms. These and other factors make diagnosing this medical condition difficult.

The best line of treatment is to monitor medications and make necessary alterations to minimize or reverse medicine-induced dementia symptoms. This might involve weaning the patient off the offending medication and substituting it with something else. Non-pharmacological treatments are also available, including cognitive-behavioral therapy, psychotherapy, and dementia support groups.^[13]