Genes that make people move more also make depression less likely, and not the other way round
A Mendelian randomisation study of 611,583 adults found that sensor measured activity lowered the odds of major depression (OR 0.74 per SD), with no sign that depression reduces activity. Self reported activity showed nothing.
Reasonable evidence with real limitations. how we score evidence
Caveat on this rating: Mendelian randomisation depends on the genetic instruments affecting depression only through activity; the authors ran sensitivity analyses for that, but it cannot be proven. European ancestry only. The protective estimate is per standard deviation of measured acceleration and does not translate into a dose. The self-report null means most survey-based evidence in this area is on weaker ground than it looks.
People who exercise are less depressed. That could be because exercise helps, or because depression stops people exercising. This study used genetics to ask which way the arrow points.
Significant findings
Choi, Chen, Stein and colleagues ran a two sample Mendelian randomisation study. The method uses genetic variants linked to a trait as a stand in for the trait itself; because genes are fixed at conception, they cannot be caused by later depression. Variants came from the largest available genome wide studies: self reported activity (n = 377,234), accelerometer measured activity (n = 91,084), and major depressive disorder (n = 143,265), a combined 611,583 adults of European ancestry.
Measured activity protected. "Mendelian randomization evidence suggested a protective relationship between accelerometer-based activity and MDD (odds ratio [OR], 0.74 for MDD per 1-SD increase in mean acceleration; 95% CI, 0.59-0.92; P = .006)."
The reverse did not hold. There was "no statistically significant relationship between MDD and accelerometer-based activity."
And what people said they did predicted nothing. There was "no significant relationship between self-reported activity and MDD" in either direction.
The authors conclude that "robust evidence supports a protective relationship between objectively assessed-but not self-reported-physical activity and the risk for MDD", and that this supports the hypothesis that raising activity "may be an effective prevention strategy for depression."
The other direction
The self report null is the caveat and the lesson. Either people misreport how much they move, or the kind of movement a wrist sensor picks up is what matters. The estimate is per standard deviation of measured movement, which is not a number of minutes.
What this does not show
This is a genetic analysis in people of European ancestry, not a trial of an exercise program. It speaks to prevention of depression, not to treatment of someone who already has it.
Worth asking
What would a week of movement look like that I would actually keep?
Source
Assessment of bidirectional relationships between physical activity and depression among adults: a 2-sample Mendelian randomization study — Choi KW, Chen CY, Stein MB, Klimentidis YC, Wang MJ, Koenen KC, Smoller JW (2019)
Top-tier peer-reviewed journal
Read the source: https://doi.org/10.1001/jamapsychiatry.2018.4175
DOI: 10.1001/jamapsychiatry.2018.4175
How this was scored
- Study design
- Cohort study
- Funding
- Funding not disclosed
- Published in
- Top-tier peer-reviewed journal
- Sample size
- 611,583
- Preregistered
- not recorded
- Conflicts disclosed
- not recorded
- Independent of proponent
- not recorded
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published September 24, 2026.
Questions
How strong is the evidence behind this?
veisund rates this source "moderate evidence". Reasonable evidence with real limitations. It scores 58 out of 100 on our published rubric. One caveat travels with that badge: Mendelian randomisation depends on the genetic instruments affecting depression only through activity; the authors ran sensitivity analyses for that, but it cannot be proven. European ancestry only. The protective estimate is per standard deviation of measured acceleration and does not translate into a dose. The self-report null means most survey-based evidence in this area is on weaker ground than it looks. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Assessment of bidirectional relationships between physical activity and depression among adults: a 2-sample Mendelian randomization study — Choi KW, Chen CY, Stein MB, Klimentidis YC, Wang MJ, Koenen KC, Smoller JW (2019). Published in: Top-tier peer-reviewed journal. DOI: 10.1001/jamapsychiatry.2018.4175. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Cohort study. Funding: Funding not disclosed. Independence from the proponent is not recorded. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.