The aim of the study was to measure the frequency of such emotional disturbances as anxiety, depression and aggression among patients treated in a pain clinic, as well as assess the factors contributing to such disorders. Research was conducted from January 2014 to April 2018 and involved patients treated in two pain clinics in the city of Warsaw, Poland. The study used the Hospital Anxiety and Depression Scale—Modified Version (HADS-M) and the Numerical Rating Scale (NSR). 1025 patients were recruited. The main reasons for their attending the pain clinic were osteoarticular pain (43.61%) and neuropathic pain (41.56%). Emotional disturbances in the form of anxiety were diagnosed in 32.39% of all the patients, depression in 17.85%, and aggression in 46.15%. The factors determining the level of anxiety in the study group were: sex, age, pain intensity and the lack of pharmacological treatment. Depression was determined by sex, pain intensity and the time of treatment in the clinic, while aggression by age and pain intensity.