Treating chronic insomnia with cognitive behavioral therapy (CBT-I) did more than help older adults sleep better — it appears to have slowed the molecular pace at which their bodies were aging, according to a secondary analysis of a randomized controlled trial published in The Lancet Healthy Longevity.
Researchers at UCLA Health tracked 92 adults age 60 and older who met criteria for insomnia disorder. Participants were randomly assigned to eight weeks of CBT-I (47 people) or a comparison condition of sleep education therapy (45 people). Blood was drawn before treatment and again 18 to 24 months later, and DNA extracted from those samples was used to calculate three separate "epigenetic clocks" — DunedinPACE, GrimAge, and a principal-component version of PhenoAge — which estimate biological aging from patterns of DNA methylation rather than the calendar.
A Measurable Slowdown in Aging's Pace
On DunedinPACE, a clock specifically designed to track the speed at which a person is aging rather than a fixed biological age, the CBT-I group showed a significantly slower pace of aging relative to the sleep-education group (difference of -0.02, 95% CI -0.04 to -0.01, FDR-adjusted p=0.03). In practical terms, participants who received CBT-I were aging more slowly at the cellular level over the study period than those who did not, while the sleep-education group's pace of aging increased slightly over the same interval.
The two other clocks, GrimAge and PCPhenoAge, trended in the same protective direction but did not reach statistical significance after adjustment for multiple comparisons — a reminder that different epigenetic clocks capture different biological signals and don't always move in lockstep.
CBT-I also outperformed sleep education on the more familiar measure of treatment success: full insomnia remission. Thirty-four percent of the CBT-I group (16 of 47) achieved remission, compared with just 13% of the sleep-education group (six of 45) — meaning people receiving the structured behavioral therapy were roughly two-and-a-half to three times as likely to see their insomnia resolve entirely.
Why Sleep and Cellular Aging Might Be Linked
CBT-I is a short, structured, non-drug program that typically combines sleep restriction, stimulus control, and cognitive techniques to correct the habits and thought patterns that perpetuate chronic insomnia. It is already the first-line treatment recommended by sleep medicine guidelines, but its downstream effects on biological markers of aging have been harder to demonstrate.
Chronic poor sleep has independently been linked to elevated inflammation, disrupted metabolic regulation, and accelerated markers of cellular senescence — all processes that epigenetic clocks like DunedinPACE are built to capture. The new findings suggest that correcting insomnia itself, not just managing its daytime symptoms, may partially reverse or blunt that biological wear.
The authors caution that this was a secondary, hypothesis-generating analysis of a modestly sized trial conducted at a single site in Los Angeles, and that a slower pace on an epigenetic clock is not the same as proof of a longer lifespan or lower disease risk. Larger, more diverse, multi-site trials will be needed to confirm whether the effect holds up and translates into measurable health outcomes.
What This Means for Patients
For older adults living with chronic insomnia, the findings add a new rationale to an already strong case for trying CBT-I before or alongside medication: it is already recommended as the first-line treatment because it works better long-term than sleep drugs and carries none of their dependency risks. This study suggests an additional potential payoff — that fixing sleep may also be doing quiet, measurable work on the biological processes tied to aging itself. Patients interested in CBT-I can ask a primary care doctor or sleep specialist for a referral, or access it through trained psychologists, sleep medicine clinics, or accredited digital CBT-I programs, several of which are covered by insurance or available through the VA and major health systems.
