Although stigma associated with psychiatric hospitalization may discourage patients from seeking care, little is known about how patients’ views change after experiencing inpatient treatment. We examined admission-to-discharge changes in attitudes toward psychiatric hospitalization among adults admitted to the Johns Hopkins Mood Disorders Units, with particular attention to stigma worry and whether those changes were related to clinical improvement. In this prospective cohort study, 122 participants were enrolled, and 64 had paired admission-discharge attitude data. Participants completed a study-specific Attitudes Questionnaire at both time points. The primary stigma item asked whether participants worried what others would think if they learned of their psychiatric admission. Paired changes were evaluated using Wilcoxon signed-ranks tests, with exploratory analyses using Kruskal–Wallis and Spearman rank correlation tests. Eight of ten paired attitude items improved significantly. Agreement with stigma worry decreased from 65.6% at admission to 39.1% at discharge, a 26.5 percentage-point reduction; mean stigma worry decreased from 3.70 to 2.92, z = 4.41, p < 0.001. Participants with high baseline stigma worry had the greatest reductions, Kruskal–Wallis χ²(2) = 16.37, p = 0.0003; mean change was −1.21 in the high-stigma group versus +0.18 in the low-stigma group, post-hoc p = 0.0001. Longer length of stay was associated with greater stigma reduction, ρ = −0.290, p = 0.020. Stigma change was not significantly associated with PHQ-9, GAD-7, or PMQ-9 improvement. These findings suggest that inpatient treatment may reduce hospitalization-related stigma through processes not explained by symptom improvement alone.