Other Conditions and Rx

Traumatic brain injury, depression, conditions that affect your oxygen levels, and medication side effects can all impact your cognition.


⏱ 4 min read

Traumatic brain injury

A traumatic brain injury is an injury that affects how the brain works. Some brain injuries may be considered ‘mild’ – like a concussion – and others more ‘severe’, if there is a skull fracture or a hit to the head that causes bleeding in the brain. Traumatic brain injury is also sometimes referred to as ‘acquired brain injury’ or ‘head injury’.

Most injuries that occur each year are mild traumatic brain injuries or concussions. This is caused by:

  • A bump, blow, or jolt to the head, or
  • By a hit to the body that causes the head and brain to move quickly back and forth.

This sudden movement can cause:

  • The brain to bounce around or twist in the skull
  • Chemical changes in the brain
  • Stretching and damaging brain cells

These changes in the brain lead to symptoms that may affect how a person thinks, learns, feels, acts, and sleeps.

Traumatic brain injuries also increase the risk of dementia.

What you can do to try to prevent a traumatic brain injury

Here are a range of actions you can take to try to prevent head injuries.

  • Buckle up every ride
    • Wear a seat belt every time you drive – or ride – in a motor vehicle.
    • Never drive while under the influence of alcohol or drugs.
  • Wear a helmet when you ride a bike
  • Prevent falls
    • Talk to your doctor to evaluate your risk for falling, and talk with them about specific things you can do to reduce your risk for a fall.
      • Ask your doctor or pharmacist to review your medicines to see if any might make you dizzy or sleepy. This should include prescription medicines, over-the counter medicines, herbal supplements, and vitamins.
    • Have your eyes checked at least once a year, and be sure to update your eyeglasses if needed.
    • Do strength and balance exercises to make your legs stronger and improve your balance.
    • Make your home safer.

Learn more about fall and injury prevention by browsing our Blog Posts on this topic and on the Parachute website.

Learn more about brain injury from the Ontario Brain Injury Association.


Studies have shown that the presence of depression nearly doubles the risk of developing dementia. However, it is a bit of a complex risk factor: depression might be a risk for dementia, but in later life dementia might cause depression.

What you can do about depression?

Treatment might help reduce the risks of cognitive decline. There are both non-drug and drug treatments available for depression.

Learn more about major depressive disorder and its treatment by exploring that topic on the Aging Minds website.

Conditions that affect your oxygen levels

There are a variety of medical conditions that might lower how much oxygen is getting to your brain, which can affect your memory, thinking, and overall brain function. These include conditions such as:

  • congestive heart failure
  • chronic obstructive pulmonary diseases (COPD) like chronic bronchitis and emphysema
  • anemia (low blood hemoglobin levels)
  • sleep apnea

What you can do about it

If you have any of these conditions, work with your health care team to manage them as best as possible, to maximize the amount of oxygen getting to your brain.

Air pollution and second-hand smoke

An emerging area of interest and relatively new risk factor is the effects of air pollution and second-hand smoke on the brain. It’s possible that air pollution has similar effects on the brain as cigarette smoking, contributing to effects on blood vessels and possibly other toxic effects on the brain as well.

What you can do about air pollutants

Where possible, reduce exposure to air pollution and second-hand tobacco smoke to reduce your risks of dementia. It will also have positive effects on your lung health and other health outcomes as well.

Medication adverse effects

Several medications have the potential for adverse effects on memory and cognitive function. Medications such as benzodiazepines (widely used to treat anxiety or insomnia), the ‘Z-drugs’ or sleeping pills like zolpidem (Ambien) and zopiclone (Imovane), some antidepressants, and many pain medications such as opioids (also known as narcotics) can result in significant cognitive impairment.

Watch out for medications that have anticholinergic side effects, such as Benadryl, Gravol, older antidepressants like amitriptyline (Elavil), and some bladder medications like oxybutynin (Ditropan) and tolterodine (Detrol).

Many of these medications can also have adverse effects on mobility and increase the risk of falls.

Medication TypeExample
BenzodiazepinesLorazepam (Ativan), alprazolam (Xanax)
Sleeping pillsZolpidem (Ambien), zopiclone (Imovane)
OpioidsMorphine, hydromorphone (Dilaudid)
Anticholinergic drugsBenadryl, Gravol, amitriptyline (Elavil), oxybutynin (Ditropan)

What you can do about medication adverse effects

It’s important to review your medications regularly with your health care team to reduce your risk of serious side effects. Many pharmacies offer services – like Ontario’s MedsCheck Program for people taking a minimum of three medications – where they can help to review your medications.

Talk with your doctor about whether ‘deprescribing’ some medications slowly and safely might make sense for you. Deprescribing is the planned and supervised process of dose reduction or slowly coming off of medication that might be causing harm, or no longer be of benefit. You can learn more about it on the deprescribing.org website.

Key points from this topic

  • Prevent head injuries by wearing a seatbelt and trying to reduce your risk of falls
  • If you have depression, get it treated
  • Manage any conditions that lower your oxygen levels
  • Where possible, reduce your exposure to air pollution and second-hand cigarette smoke
  • Periodically review your medications with your health care team to ensure you are getting maximum benefit and minimizing adverse effects on your memory and thinking


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Anthony Levinson

Anthony J. Levinson, MD, MSc, FRCPC

Neuropsychiatrist, Professor; Faculty of Health Sciences, McMaster University

About this Project

Who authored and edited this page?

This page was developed by the Division of e-Learning Innovation team and Dr. Anthony J. Levinson, MD, FRCPC (Psychiatry). Dr. Levinson is a psychiatrist and professor in the Department of Psychiatry and Behaviour Neurosciences, Faculty of Health Sciences, McMaster University. He is the Director of the Division of e-Learning Innovation, as well as the John Evans Chair in Health Sciences Educational Research at McMaster. He practices Consultation-Liaison Psychiatry, with a special focus on dementia and neuropsychiatry. He is also the co-developer of the iGeriCare.ca dementia care partner resource, and one of the co-leads for the McMaster Optimal Aging Portal. He and his team are passionate about developing high-quality digital content to improve people's understanding about health. By the way, no computer-generated content was used on this page. Specifically, a real human (me) wrote and edited this page without the help of generative AI like ChatGPT or Bing's new AI or otherwise.

Are there any important disclosures or conflicts of interest?

Dr. Levinson receives funding from McMaster University as part of his research chair. He has also received several grants for his work from not-for-profit granting agencies. He has no conflicts of interest with respect to the pharmaceutical industry; and there were no funds from industry used in the development of this website.

When was it last reviewed?

August 22, 2023

What references and evidence were used to create this content?

Content was written and adapted based on credible, high-quality, non-biased sources such as MedlinePlus, the National Institutes for Mental Health, the McMaster Optimal Aging Portal, the American Psychiatric Association, the Cochrane Library, the Centre for Addictions and Mental Health (CAMH) and others. In particular, evidence-based content about dementia risk reduction was also derived from the World Health Organization and the Lancet Commission reports. Please see additional references on the e-learning lesson landing page

Who funded it?

The initial development of some of this content was funded by the Centre for Aging and Brain Health Innovation, powered by Baycrest. Subsequent funding was through support from the McMaster Optimal Aging Portal, with support from the Labarge Optimal Aging Initiative, the Faculty of Health Sciences, and the McMaster Institute for Research on Aging (MIRA) at McMaster University, and the Public Health Agency of Canada. There are no conflicts of interest to declare. There was no industry funding for this content.