Photo by Chandra Oh on Unsplash

For months, I have been caring for a man with severe nerve pain from cancer that has invaded the nerves of his shoulder and arm. The pain is burning, lancinating, relentless. He is on an elaborate regimen of opioids and adjuvant analgesics, and has been through a series of interventional procedures, none of which made a lasting difference.

What strikes me most is this: when he comes to the clinic every few weeks, his reports vary wildly. Some days the medications are working, the pain is manageable, and he is out in the yard, tinkering in his workshop, or taking his usual walk. Other days, nothing works. He wants to stop everything. He is disgusted by the pain and retreats to a back room for hours, away from his family. Nothing else has changed. His disease is stable. His regimen is the same. What changes, as far as I can tell, is his emotional and cognitive response to the pain, which swings widely and seems to decide whether his regimen feels adequate or useless.

He is not the only person who presents this way. In my clinic, I have often observed similar cases. Two patients with similar cancers and similar pain scores, and one moves through treatment with a kind of steadiness, while the other is overwhelmed, or, as with my patient, the same person on two different days. We often look to biological factors to explain these differences, such as receptors, metabolism, or disease burden. They all have their role. But anyone who does this work long enough begins to suspect that something else is doing much of the heavy lifting – not just how much pain a person has, but how they think and feel about it, and how unstable those thoughts and feelings can be.

A new study in JCO Oncology Practice provides valuable insights into the experiences of patients with cancer-related pain. Zhao and colleagues followed 26 patients with advanced cancer for a full month, asking them each day about their pain, their mood, their opioid use, and their worries about pain. Most studies in this space capture one or two snapshots; this one captured 28 days of lived experience, nearly 500 daily check-ins, which is long enough to see how a single person changes from one day to the next, not just how patients differ from one another.

Two findings worth highlighting:

The first: it’s the worst pain that does the damage. When patients’ worst pain spiked above their own usual level, almost everything else got worse that same day — pain interfered more with daily life, mood dropped, opioid use went up, and, strikingly, the opioids felt like they were working less well. Average pain and least pain mattered far less. The peak is what truly causes distress. In a clinical setting, we often anchor to average pain: “How’s your pain been, generally?” However, this is a reminder that it is the spikes, the breakthrough moments, that condense the suffering.

The second is subtler, and I think more important. The researchers looked not only at how much people worried about their pain, but at how much that worry swung from day to day. And it turned out that the swing itself, the instability, the ups and downs, predicted worse outcomes. Patients whose pain-related worry stayed steady, even when it was steadily high, were more predictable and seemed better able to adapt. It was the patients whose worry lurched up and down who had the hardest time: on a high-pain day, their pain interfered more, their mood fell further, and their medications felt less effective. The chaos, not just the degree of worry, was the problem.

That reframes something I’ve seen at the bedside for years. A worried mind doesn’t just feel pain – it amplifies it, and when that amplification is unpredictable, coping skills can’t get a foothold. It also offers a plausible, human-scale explanation for something that otherwise looks like pharmacology: why the same dose of the same opioid helps so much on some days and so little on others. Part of the answer may lie not only in the patient’s receptors, but in the brain, where pain is actually constructed.

I want to be careful with that phrase because, as it has been used, “it’s in your head” dismisses pain and implies it isn’t real. The truth is closer to the opposite. Pain is in the head – not because it’s imagined, but because the brain is where pain is made and processed. Every pain experience is constructed by the brain from the combination of nerve signals, memory, attention, fear, and meaning. The emotional and cognitive layers aren’t a distortion sitting atop “real” pain; they are integral to how pain is experienced. So when worry intensifies suffering, it doesn’t mean the pain is any less valid. Instead, it indicates that the brain – doing exactly what brains do – is turning the volume up.

A word of caution on language: the clinical term here is “catastrophizing,” and patients and researchers have rightly pushed back on how stigmatizing it can sound — as it can imply that someone who is afraid is simply overreacting. Worrying about pain when facing advanced cancer isn’t a character flaw. It’s a natural reaction to a frightening situation. The point isn’t to judge the worry; it’s to notice when it becomes severe, persistent, or unstable, because that’s when it can become harmful.

So what do we actually do with this? Three things stand out to me.

Monitor the worst pain, not just the average. Asking specifically about peak and breakthrough pain, and watching for the days when levels spike, may help flag the moments when a patient is most at risk.

Treat mood and worry as vital signs. We check pain scores reflexively; we should be just as routine about asking how someone is coping emotionally and how steady or shaky that coping feels day to day.

Build support around the cognitive and emotional side of pain. Cognitive-behavioral approaches, such as gentle reframing, reassurance, grounding, and acceptance, have proven effective for chronic pain. However, this can be challenging. I referred my patient for CBT, and he resisted it; when he did try, it didn’t land. A weekly appointment to discuss thoughts can seem irrelevant to someone experiencing intense pain in the moment. That’s exactly why the approach behind this study interests me. The data came from an app delivering pain-CBT skills in small daily doses, with the option to provide the right prompt on high-pain, high-worry days when it’s actually needed. This way, we can address worries right when they arise, rather than waiting for the patient to initiate the conversation.

None of this replaces good analgesia. But it’s important to consider the broader perspective. To understand why the same treatment can help a patient on one day but fail on another, we have to take the inner experience of pain as seriously as the physical one. That, to me, is the most human element of all.