Why side effects, “treatment failure,” and medication mismatches may have more to do with biology than behavior

There is a quiet assumption built into modern medicine—rarely spoken aloud, but often felt by those sitting on the receiving end of it.

If the medication doesn’t work…
something must be wrong with the patient.

Perhaps they didn’t take it correctly.
Perhaps they’re “sensitive.”
Perhaps they’re “noncompliant.”

It’s a subtle shift in language, but a powerful one. It shifts the problem’s center of gravity away from the system—and places it squarely on the individual.

But what if that assumption is not just incomplete… but fundamentally flawed?

What if the issue isn’t compliance at all?
What if it’s compatibility?

The Great Medication Paradox

Consider a familiar scenario.

Two individuals are prescribed the same antidepressant.

One begins to feel relief within weeks—their mood stabilizes, their thoughts soften, and life becomes more manageable.

The other experiences insomnia, agitation, nausea, and a sense that something is deeply “off.” They stop the medication, are discouraged, and are often told, “Let’s try something else.”

From the outside, it appears to be a difference in response.

From the inside, it feels like a difference in reality.

For decades, medicine has largely explained this in terms of probability. No medication works for everyone, and variability is expected. But that explanation, while practical, lacks precision.

(Continue reading You’re Not Noncompliant—You’re Complex on Substack on 3/23/26.)

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After the Lens…

You’ve just read an article from The Lens of Reason—a space for examining the patterns beneath our assumptions, the psychology beneath our certainty, and the quiet forces shaping our decisions long before we notice them.

If you liked the real-world hidden variables in The Missing Variable, you’ll love what happens when those same ideas play out in fiction—the new Fusion Heart novel is live.

If your curiosity leans toward the imaginative edge of these ideas, your questions unfold in a different form inside The Realm Between Realms, where speculative fiction explores how choice, consequence, and consciousness might shape The Library of Unwritten Futures.

I’m Dr. Jill Fandrich, author of The Missing Variable. I write for readers who believe clarity isn’t found by avoiding complexity, but by learning how to look at it differently.

Until next time, keep the lens clean.