Rheumatoid arthritis is a chronic systemic inflammatory disease that affects approximately 0.5-1% of the world population. The current approach to this disease is to start an intensive treatment without delay once the disease has developed. Various studies in the literature have shown that combination of disease modifying antirheumatic drugs such as sulfasalazine and chloroquine offers a more advantageous treatment. Although these drugs may cause central nervous system adverse effects such as serious psychiatric problems including mania and psychosis, these symptoms have been reported to occur only infrequently. The present case study reports a female patient who was hospitalized due to bipolar affective disorder-mixed episode. She had been receiving 250 mg/day chloroquine for 9 months for rheumatoid arthritis without exhibiting any adverse psychiatric effects. However, upon receiving a combination of 250 mg/day chloroquine and 2 gr/day sulfasalazine, she developed serious psychiatric symptoms.