BackgroundGastrointestinal (GI) cancer diagnosis can adversely affect the mental health (MH) of household members, including spouses and children. We sought to examine potential changes in MH claims in households following an index patient’s GI cancer diagnosis. MethodsHouseholds of patients with a GI cancer diagnosis were identified using the IBM MarketScan database (2014–2019) and matched with households of patients without cancer. MH-related visits of spouses and children were assessed in the 12 months before and after the index date of diagnosis. Changes were compared between the two cohorts using difference-in-difference (DID) analysis. ResultsAmong 40,650 households in the spouse analysis and 20,014 households in the child analysis, 25.1% (n = 10,210) and 26.8% (n = 5,368) were households in which there was a patient with a GI cancer. Univariable DID analysis demonstrated that households with a GI cancer had a greater increase in anxiety-related (spouses, 2.2% vs 0.7%; children, 2.0% vs 1.1%), mental illness (MI)–related (spouses, 3.2% vs 1.2%; children, 3.0% vs 1.6%), and overall MH-related visits (spouses, 3.3% vs 1.4%) versus the control group (all P < .05). In adjusted DID analysis, spouses, children, and households with a GI cancer diagnosis had a 2.1%, 1.6%, and 2.3% absolute risk increase of MI-related visits, respectively, compared with non-cancer households (all P < .05). ConclusionIn a cohort of privately insured households, coinsured spouses and children of patients with a GI cancer diagnosis had a higher risk of MH-related claims versus households without a GI cancer diagnosis. The data highlight the importance of family counseling and psychological support when a loved one is diagnosed with cancer.