Effects of opioids on cognition in older adults

The effects of opioids on cognition in older adults with cancer and chronic non-cancer pain: A systematic review. – PubMed – NCBI – J Pain Symptom Manage. Oct 2019

Opioids are prescribed to manage moderate to severe pain and can be used with older adults; however, they may lead to several adverse effects, including cognitive impairment.

To identify, appraise and synthesise evidence on

  • i) the impact of opioids on cognition in older adults with cancer/chronic non-cancer pain, and
  • ii) screening tools/neuropsychological assessments used to detect opioid-induced cognitive impairment.


up to December 2018.

  • Randomised controlled trials,
  • quasi-experimental studies and
  • observational studies

of adults aged ≥65 with cancer/chronic non-cancer pain taking opioids were included. A narrative synthesis was conducted.


From 4,036 records, 10 met inclusion criteria.

When such a seemingly broad search produces so few studies, bias seems unavoidable because 10 studies cannot be representative of the other 4,036.

Five studies used one screening tool and five used a range of neuropsychological assessments; assessing 14 cognitive domains.

Most studies demonstrated no effect of opioid use on cognitive domains, whilst four studies showed mixed effects. In particular, attention, language, orientation, psychomotor function and verbal working/delayed episodic memory were worsened.

Changes to cognitive function were predominantly observed in studies with higher mean doses of opioids (120mg-190.7mg oral morphine equivalent daily dose).

My severe cognitive impairment is not due to the opioids I take, but to the known anticholinergic effects of the tricyclic antidepressant I have to take.

I know this because I’ve been taking opioids for over 2 decades and only added the tricyclics a few years ago. Within months, I started having trouble finding words.

But no one is complaining about even the nastiest side-effects of non-opioid drugs being prescribed off-label for pain. Just the fact that a medicine is NOT an opioid gives it an aura of benevolence that isn’t questioned.


Both improvements and impairments to cognition were observed in studies with higher mean opioid doses.

Think about that for a moment: “improvements to cognition were observed” as a side-effect of “high mean opioid doses”.

Amidst all the current hype and hyperbole about the “dangers” and “addictiveness” of opioids, I’m surprised they even published that sentence.

Even though both “improvements AND impairments” were observed, I expect most people will fixate on the “impairments” because that is what’s “expected”. Any positive results of “opioids therapy” are almost unimaginable, especially when the “experts” insist our opioids don’t even do the one thing we take them for: relieve pain.

This is the first time I’ve seen any mention of improvements to cognition from taking opioids; I’m sure the researchers were very surprised by these unexpected results.

Their objective stated:

To identify, appraise and synthesize evidence on screening tools/neuropsychological assessments used to detect opioid-induced cognitive impairment.

They were clearly set up to find and measure the negative impact of opioids on our minds, so they must have been shocked to find that some people actually had opioid-induced cognitive improvement, not just impairment.

But then when I think back to my rare episodes of unusual productivity, they were on days when I was able to stifle my chronic pain almost completely. In that state, I can feel my brain working unusually well, without the usual mental “brain fog” that makes my thoughts wander around in circles.

In clinical practice, a brief screening tool assessing

  • attention,
  • language,
  • orientation,
  • psychomotor function, and
  • verbal working/delayed episodic memory,

may be beneficial to detect worsening cognition in older adults with chronic pain using opioids.

Unmentioned is that the same tool will also detect improving cognition (like what happened in their study)?

The more I think about this, the more sense it makes. Pain causes tremendous disruptions in our mental state with its alarming distractions and futile calls to action, like an alarm that’s stuck.

When that pain is eased, the interference stops and we can concentrate and focus again without constantly being tripped and pushed off-topic by pain signals.

So it makes perfect sense that an effective dose of opioids would improve cognition, not due to the drug itself, but because the drug “puts out the fire” of pain.


1 thought on “Effects of opioids on cognition in older adults

  1. GZB

    I agree, we certainly won’t be hearing a lot about the cognitive improvements. It doesn’t take a brain surgeon to understand that anyone’s outlook and mental capacity would be improved when you muzzle chronic pain.

    Liked by 1 person


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