Simple Summary: Papillary thyroid cancer diagnosis is a significant source of worry to patients, despite its relatively good prognosis. Such significant distress may prompt patients to receive surgical treatment, even when active surveillance may be a safer alternative. Patients with pre-existing anxiety and depression may be particularly prone to opting for surgical treatment. We collected data on the time between fine-needle aspiration (FNA) diagnosis and surgical treatment of a cohort of patients seen at a large tertiary center in New York in 2018–2020 and investigated mental health status as potential predictors. We found that pre-existing anxiety and depression may lead to shorter times for surgical intervention for thyroid cancer. Our study adds to the limited literature on mental health predictors of thyroid cancer decision making. (1) Background: A pre-existing psychiatric condition may impact decision making by patients and/or physicians following a thyroid cancer diagnosis, such as potentially electing surgery over active surveillance, thus shortening the time to cancer removal. This is the first study to investigate the association between pre-existing anxiety and/or depression and time to receive surgical treatment for thyroid cancer. (2) Methods: Retrospective data were collected from 652 surgical thyroid cancer patients at our institution from 2018 to 2020. We investigated the time between thyroid cancer diagnosis and surgery, comparing patients with pre-existing anxiety and/or depression to those without. (3) Results: Patients with anxiety, depression, and both anxiety and depression had a significantly shorter time between diagnosis and surgery (51.6, 57, and 57.4 days, respectively) compared to patients without (111.9 days) (p = 0.002, p = 0.004, p = 0.003, respectively). (4) Conclusions: Although little is known about the impact of pre-existing psychiatric conditions in the decision-making process for thyroid cancer surgery, this present study showed that anxiety and/or depression may lead to more immediate surgical interventions. Thus, psychiatric history may be an important factor for physicians to consider when counseling patients with thyroid cancer. [ABSTRACT FROM AUTHOR]