**Background:** Cancer survivors are at risk for psychological morbidity, including anxiety, depression, and cognitive difficulties, which impact quality of life. Previous estimates suggest 14–24% of survivors experience clinical depression and approximately 10% report clinical anxiety, compared to population estimates of 5% and 7%, respectively. Up to 75% of survivors report cognitive difficulties. However, most research has focused on breast cancer survivors, and population-level data across all cancer types is limited. This study aimed to investigate whether cancer survivors have greater self-reported mental health symptoms than individuals without a cancer history using a nationally representative US sample, and to examine the effect of time since diagnosis.
**Methods:** Data were drawn from the National Health and Nutrition Examination Survey (NHANES) 2015–2016 and 2017–2018 cycles. Participants aged 18–79 with complete data on mental health outcomes, age, gender, race/ethnicity, education, and cancer history were included. The primary outcomes were three single-item measures: anxiety ('How often do you feel worried or anxious?'), depression ('How often do you feel depressed?'), and concentration difficulties ('Do you have serious difficulty concentrating?'). Anxiety and depression were dichotomized as 'at least once a month' versus 'less than once a month.' Cancer history was defined as a self-reported diagnosis of cancer or malignancy, excluding non-melanoma skin cancer. Logistic regression models were used, adjusted for age, gender, race/ethnicity, and education. Polychoric correlations between outcomes were calculated among cancer survivors. A secondary analysis examined time since diagnosis. Sensitivity analysis using propensity score stratification was performed.
**Key Results:** Of 10,337 participants, 691 (6.7%) reported a cancer history. Cancer survivors were older (median age 63 vs. 45 years), more likely to be female (58% vs. 51%), non-Hispanic White (76.5% vs. 61.3%), and had slightly higher education (69% vs. 64% with some college). Median time since diagnosis was 8 years (IQR 4–16). Prevalence of anxiety was similar between groups (45.8% cancer history vs. 46.9% no cancer history), as was depression (19.7% vs. 20.0%). Concentration difficulties were more common in cancer survivors (11.3% vs. 9.0%). After adjustment, cancer survivors had significantly higher odds of concentration difficulties (AOR 1.38, 95% CI 1.00–1.90), but not anxiety (AOR 1.12, 95% CI 0.87–1.43) or depression (AOR 1.11, 95% CI 0.87–1.41). By tumor type, upper gastrointestinal cancer was associated with higher odds of anxiety (AOR 2.18, 95% CI 1.13–4.21) and depression (AOR 3.66, 95% CI 1.28–10.5). Colorectal cancer (AOR 2.40, 95% CI 1.07–5.37) and breast cancer (AOR 2.07, 95% CI 1.02–4.20) were associated with higher odds of concentration difficulties. Gender modified the effect on concentration difficulties (p-interaction=0.04), with larger effects for women (AOR 1.66, 95% CI 1.16–2.37) than men (AOR 0.94, 95% CI 0.56–1.58). Time since diagnosis was not associated with any mental health outcome. Strong correlations were found among cancer survivors: anxiety-depression r=0.81 (95% CI 0.74–0.86), anxiety-concentration r=0.52 (95% CI 0.40–0.64), depression-concentration r=0.64 (95% CI 0.53–0.74).
**Clinical Implications:** This large population-based study found that cancer survivors do not report higher rates of anxiety or depression than the general population, but do report significantly more concentration difficulties, particularly among women and survivors of colorectal and breast cancers. The strong correlations between anxiety, depression, and concentration difficulties suggest these symptoms cluster together, but the cross-sectional design precludes causal inference. Clinicians should be aware that concentration difficulties may persist long after treatment (median 8 years post-diagnosis) and may be more prominent than mood symptoms in survivorship care. Limitations include the use of single-item measures, over-representation of non-Hispanic White and well-educated participants, lack of data on disease stage and treatment, and small sample sizes for some tumor types. Further longitudinal research is needed to understand causal relationships and to develop targeted interventions.