Objective: To observe the effects that the COVID-19 pandemic has had on patients with contamination fear at obsessive-compulsive disorder (OCD), and how this can be used to improve psychotherapeutic treatment. Materials and methods: 33 patients were involved, divided into 2 groups, in one of which we used additional experimental features of psychotherapy. OCD total condition and separate symptoms were assessed using Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Results: Patients, included in Group A, showed significantly better improvement in both total Y-BOCS score, as well as in particular symptoms connected with so-called mental contamination. Conclusions: Adding reality-based and emotionally significant features of contamination control and prevention to standard cognitive-behavioral therapy protocol may seriously improve outcomes in the treatment of mental contamination obsessions. The period of pandemics, as well as post-pandemic, can be used for intense further research in this area in a larger selection of patients. Long-term follow-up is recommended to clarify the stability of positive changes.

It is widely accepted that mental disorders cause significant damage to human health. The mechanisms of their pathogenesis have not yet been fully clarified. Hereditary, environmental, metabolic, and other factors are important in these mechanisms. Calcium is considered a possible participant in the mechanisms of pathogenesis. Its serum level is controlled by hormonal regulation. Thyroid and other disorders lead to calcium levels disturbances (hypocalcemia and hypercalcemia). Various physical and mental symptoms accompany these conditions. To clarify the pathogenetic mechanisms of mental disorders and to develop new drug interventions, it is essential to clarify the role of various participants in them, including calcium. The medications that regulate the calcium level, particularly calcium channel blockers, can help develop new treatment methods for mental disorders. It is necessary to study the mentioned drugs’ mechanisms of action on mental disorders and the possible ways of their improvement and practical application.