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Depression as an Independent Predictor of Cost-Related Medication Nonadherence Among U.S. Adults

Based on a 2024 analysis of over 450,000 U.S. adults, depression is an independent predictor of cost-related medication nonadherence, doubling the odds of missing prescribed drugs due to cost even after adjusting for socioeconomic factors, with income and insurance status emerging as the strongest additional drivers of this disparity.

Original authors: Oluwapelumi Odubunmi, Adedapo Ogunlewe, Idris Idenyi, Abdullah Adeniji-Bello

Published 2026-07-03

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Oluwapelumi Odubunmi, Adedapo Ogunlewe, Idris Idenyi, Abdullah Adeniji-Bello

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

The Big Picture: A Double Trouble

Imagine your health is a car, and your medications are the fuel. For many people, keeping that car running is hard enough. But for people with depression, the paper suggests they face a "double trouble" situation.

First, they have the engine trouble of depression itself (low motivation, brain fog, feeling hopeless). Second, they face the external obstacle of the fuel being too expensive. This study looked at over 450,000 adults in the U.S. to see if having depression makes it more likely that you'll skip your medicine because you can't afford it.

The short answer: Yes. Even when you account for how much money someone makes or if they have insurance, having depression doubles the odds that a person will skip their medication due to cost.

How They Did It: The "Snapshot"

The researchers didn't follow people over years; they took a giant "snapshot" of the U.S. population in 2024 using data from the CDC's Behavioral Risk Factor Surveillance System (BRFSS).

Think of it like taking a photo of a massive crowd at a concert. Instead of asking everyone individually, they used a special camera (statistical software) that ensures the photo represents the whole country accurately, not just the people standing in the front row. They asked two main questions:

The Exposure: "Has a doctor ever told you that you have depression?"
The Outcome: "In the last year, did you need a prescription but couldn't afford it?"

The Findings: Who is Struggling?

1. The Depression Gap
If you look at the crowd, about 10% of people without depression skipped meds due to cost. But for people with depression, that number jumped to 21%.

The Analogy: Imagine two groups of people trying to climb a hill. The group without depression has a 10% chance of slipping and falling. The group with depression has a 21% chance. Even if you give both groups the same shoes (insurance) and the same backpack weight (income), the group with depression is still significantly more likely to slip. The study suggests the "slipping" isn't just about the hill being steep; it's also about the internal struggle of the climb itself.

2. The Money Mountain
The study found that money is the biggest factor of all.

The Gradient: Think of income as a ladder. The higher you are on the ladder, the easier it is to buy meds.
- People earning over $200,000 are at the top.
- People earning less than $15,000 are at the very bottom.
- The Result: People at the bottom are 7 times more likely to skip meds than those at the top.
The Middle Class Surprise: Even people making $100,000–$ 200,000 (who you might think are "safe") were twice as likely to skip meds compared to the super-rich. This suggests that even middle-class families are feeling the pinch of high drug prices.

3. The Insurance Shield
Having insurance acts like a shield against the cost.

People without any insurance were 5 times more likely to skip meds than those who are insured.
Interestingly, retired people (who usually have Medicare) were much less likely to skip meds than working adults. This suggests that the "working-age" population is the most vulnerable group, caught between being too young for Medicare and often lacking good employer benefits.

4. Other Patterns

Women were more likely to skip meds than men.
Racial and ethnic minorities faced higher odds of skipping meds compared to White adults.
Younger adults (25–34) were the most likely to skip meds, likely because they are in the "coverage gap"—too old for Medicaid in many places, but not yet eligible for Medicare.

What the Paper Says (and Doesn't Say)

What the paper claims:

Depression is an independent predictor. This means it's not just that depressed people are usually poorer; even if a depressed person and a non-depressed person have the exact same income and insurance, the depressed person is still twice as likely to skip meds.
The reasons might be internal: Depression can make it hard to organize your life, remember to refill prescriptions, or fight through the bureaucracy of insurance. It's like trying to navigate a maze while your brain is foggy; the maze (the healthcare system) is hard enough for anyone, but it's nearly impossible for someone with depression to navigate efficiently.

What the paper does NOT claim:

It does not prove cause and effect. Because this was a "snapshot" (cross-sectional) study, we don't know if the depression caused the skipping, or if the stress of skipping meds made the depression worse. It's a chicken-and-egg situation that this specific study cannot solve.
It does not test new treatments. The paper doesn't say, "If we give free therapy, costs will drop." It only identifies the problem.
It does not know which meds were skipped. The data didn't say if people skipped their antidepressants specifically or their heart or diabetes meds. It just asked about any prescription.

The Bottom Line

The paper concludes that solving the problem of expensive medicine isn't just about giving people more money. While money and insurance are the biggest factors, depression itself adds a unique layer of difficulty.

To fix this, the authors suggest we need to treat the "engine trouble" (depression) and the "fuel cost" (affordability) as one big problem, not two separate ones. They suggest that simply handing someone a prescription isn't enough; we need to help them navigate the system and ensure they can actually afford the fuel to keep their health engine running.

Technical Summary: Depression as an Independent Predictor of Cost-Related Medication Nonadherence Among U.S. Adults

Problem Statement
Cost-related medication nonadherence (CRN)—defined as skipping, reducing, or delaying prescribed medications due to financial constraints—remains a critical public health challenge in the United States, disproportionately affecting low-income, uninsured, and marginalized populations. While the economic burden of depression is well-documented, the specific role of depression as a barrier to medication affordability remains underexamined at the population level. Existing literature suggests a bidirectional relationship where depressive symptoms (e.g., cognitive difficulty, hopelessness) may impair navigation of insurance systems, while financial burdens limit access. However, it remains unclear whether depression confers an independent risk of CRN beyond the confounding effects of socioeconomic disadvantage (income, insurance, education).

Methodology
This study employed a cross-sectional design utilizing data from the 2024 Behavioral Risk Factor Surveillance System (BRFSS), a nationally representative telephone survey of non-institutionalized U.S. adults.

Sample: The analytic sample consisted of 453,453 adults with complete data on the primary exposure, outcome, and covariates.
Exposure: Lifetime diagnosis of depression (variable ADDEPEV3), coded as a binary variable (yes/no).
Outcome: Cost-related medication nonadherence in the past 12 months (variable MEDCOST1), coded as a binary variable (yes/no).
Covariates: The analysis adjusted for age, sex, race/ethnicity, educational attainment, annual household income, health insurance status, and employment status.
Statistical Analysis: Survey-weighted logistic regression (PROC SURVEYLOGISTIC in SAS 9.4) was used to estimate unadjusted and adjusted odds ratios (ORs and aORs) with 95% confidence intervals (CIs). All analyses accounted for the complex survey design using BRFSS-specific weight (_LLCPWT), stratification (_STSTR), and primary sampling unit (_PSU) variables.

Key Results

Prevalence: The weighted prevalence of CRN was significantly higher among adults with a lifetime depression diagnosis (21.1%; 95% CI: 20.55–21.73) compared to those without (9.9%; 95% CI: 9.67–10.15).
Independent Association: After full adjustment for socioeconomic and demographic factors, depression remained a strong, independent predictor of CRN. Adults with depression had 2.37 times the odds of missing medication due to cost compared to those without depression (aOR = 2.37; 95% CI: 2.25–2.50).
Socioeconomic Gradients:
- Income: A steep, continuous gradient was observed. Adults earning <$15,000 had 7.17 times the odds of CRN compared to those earning ≥$200,000 (aOR = 7.17). Notably, even middle-income groups ( $100,000–$ 200,000) had more than double the odds of nonadherence relative to the highest income group.
- Insurance: Uninsured adults had nearly five times the odds of CRN compared to insured adults (aOR = 4.81).
- Demographics: Women, racial/ethnic minority groups (particularly Multiracial and Hispanic adults), and working-age adults (especially 25–34 years) exhibited significantly higher odds of nonadherence. Conversely, retired adults had lower odds (aOR = 0.49), likely attributable to Medicare coverage.

Key Contributions

Independent Risk Factor: The study establishes that depression is an independent predictor of cost-related medication nonadherence. The association persists even after rigorous adjustment for income, insurance, and employment, suggesting that the neurobiological and psychological features of depression (e.g., executive dysfunction, anhedonia) create barriers to medication adherence distinct from financial hardship alone.
Population-Level Evidence: By utilizing a large, nationally representative dataset (N > 450,000), the findings provide robust evidence that the risk of CRN extends beyond the lowest income brackets, affecting middle-income households and diverse demographic groups.
Policy-Relevant Stratification: The analysis highlights specific high-risk subgroups, including working-age adults and racial/ethnic minorities, who face compounded barriers due to structural gaps in insurance coverage and systemic inequities.

Significance and Claims
The paper claims that the minimal attenuation between unadjusted and adjusted estimates indicates that the mechanisms linking depression to nonadherence are not solely financial. Consequently, the authors argue that addressing medication affordability alone is insufficient for this population. The findings underscore the necessity for integrated strategies that simultaneously address mental health treatment and medication affordability.

Specifically, the authors suggest that policy interventions should include:

Robust enforcement of the Mental Health Parity and Addiction Equity Act.
Continued expansion of insurance coverage (e.g., Medicaid) for working-age adults.
The integration of financial navigation support into routine depression care.

The study concludes that while income and insurance are the strongest structural predictors, the independent effect of depression necessitates a dual-focus approach in public health policy to effectively reduce cost-related nonadherence. The authors acknowledge limitations inherent to the cross-sectional design (precluding causal inference), self-reported data, and the exclusion of institutionalized populations, framing their conclusions as evidence for the need for integrated care models rather than definitive causal proof.