Background and aim Psychiatric pathology does not always start on its own but may be conditioned or triggered by a comorbidity with a high impact on the human psyche. When there are comorbidities, psychiatric pathology can occur due to the high diagnostic burden. Our study aims to find out if there is a correlation between the diagnosis of breast cancer and its severity,and psychiatric symptoms such as depressive mood, atypical anxiety, or even autolytic ideation that directly influence the quality of life of patients. Materials and methods The study is a prospective, cross-sectional, single-center study carried out between December 2023 and June 2024 at the Mureș County Clinical Hospital in Romania. The sample population had to be at least 18 years old and had to bediagnosed with breast cancer recently.We applied two tests, WHODAS 2 (World Health Organization's Disability Assessment Schedule 2.0) and level 1 (level 1 of cross-sectional measurements of symptoms), to be able to measure and aid assessment of mental health domains that are important across psychiatric diagnoses and also the degree of disability triggered by breast cancer. The statistical analysis included descriptive statistics and interferential statistics. Statistical tests, such as Shapiro-Wilk, Kruskal-Wallis, and Mann-Whitney U tests with Bonferroni correctiontests, were used.The p-value was set to 0.05 with a confidence interval (CI) of 95%. Results The study included 120 women diagnosed with breast cancer, with a mean age of 56.64 ± 9.46 years. Regarding the severity of the diagnosis, 44 women (36.66%) had non-invasive cancer, 58 (48.33%) had invasive cancer, and 18 (15%) had metastases.There was a statistically significant difference between three of the five selected level 1 domains across cancer types.The WHODAS 2.0 disability scores showed a significant difference between groups (p < 0.001). Subjects with non-invasive cancer had the lowest WHODAS 2.0 score, followed by the invasive group, while metastases had the highest score. Conclusions Following the application of the two tests, level 1 and WHODAS 2.0, to our group of subjects, statistically significant differences were observed between the three categories of subjects. The degree of disability and the occurrence of psychological symptoms differed according to the severity of breast cancer. Adapting to the status of an oncological patient entails multiple changes from a psycho-emotional, social, occupational, and professional point of view. Although the most recent medications prolong survival, a holistic approach that considers psychological aspects can improve patients' long-term results.