Near-infrared spectroscopy and plasma homovanillic acid levels in bipolar disorder: a case report
The patient was a 22-year-old man who had no history of psychiatric illness. He was admitted to our hospital due to major depression that was diagnosed according to the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition, with moderate sadness, agitation, retardation, and difficulty in concentrating. The clinical course after admission is summarized in . We treated the patient with paroxetine and lorazepam for about 4 weeks, but treatment was not successful. On day 4, his Montgomery Åsberg Depression Rating Scale (MADRS) score was 44, and his plasma levels of HVA and MHPG were 4.6 ng/mL and 1.9 ng/mL, respectively. shows the waveform of [oxyHb] during the cognitive activation of the word fluency task. NIRS signal changes were measured during a 10 second pretask baseline period, a 60 second task period, and a 55 second posttask baseline period. The initial syllables assigned were changed every 20 seconds (/a/, /ka/, and /sa/, respectively) during the 60 second task period. During the task period, the patient was instructed to generate as many Japanese words beginning with the designated syllable as possible. In the pretask and the posttask baseline periods, the patient was instructed to repeat a train of syllables (/a/, /i/, /u/, /e/, and /o/). He sat on a chair in a room with daylight with his eyes open throughout the measurements. We focused on increases in [oxyHb], because this appears to reflect task-related cortical activation more directly than decreases in [deoxyHb]. We defined the patterns of NIRS waveforms using the grand average waveforms in the frontal region (CH 25–28, CH 36–38, and CH 46–49; ) and two simple visual indices, integral value, and centroid value. The integral value describes the size of the hemodynamic response during the 60 second activation task period, whereas the centroid value serves as an index of time course changes throughout the task, with periods representing the timing of the hemodynamic response. A recent study reported that the optimal threshold of the centroid value of the frontal region between major depressive disorder and two other disorders (schizophrenia and bipolar disorder) is 54 seconds (major depressive disorder < other 2 disorders). On day 4, the centroid value of the grand average in the central region was 68.6 seconds (), and the NIRS waveforms showed an [oxyHb] reincrease in the posttask period (CH 34, 35, 36, 39, 45, 46, 47, and 49; ), which is characteristic of schizophrenia.,,– On day 25, his MADRS score was 40, his plasma HVA level was markedly higher at 49.3 ng/mL, and his plasma MHPG level was 1.6 ng/mL. On day 27, he was voluntarily discharged from the hospital, but was still in a depressive state. On day 30, 3 days after leaving the hospital, he became manic and was readmitted to our hospital. He was in a state of psychotic mania with elevated mood, grandiosity, aggression, auditory hallucination, and thought broadcast, with a Young Mania Rating Scale (YMRS) score of 48. Paroxetine and lorazepam were discontinued. We subsequently treated him with lithium, risperidone, and zotepine for approximately 3 weeks, and his manic state improved. On day 46, his YMRS score was 29, and plasma levels of HVA and MHPG were 17 ng/mL and 1.3 ng/mL, respectively. However, he refused drugs because of extrapyramidal symptoms and became manic with psychotic symptoms again. Therefore, we tried a combination of lithium, olanzapine, and zotepine, and the treatment was successful. On day 77, the NIRS waveforms turned to a negative pattern (), which was defined by an integral value of the grand average in the central region <0, whereas there were [oxyHb] reincreases in the posttask period (CH 33, 41, 42, 43, 44, 51, and 52). On day 99, his YMRS score decreased to 3, and his plasma levels of HVA and MHPG were 8.7 ng/mL and 1.9 ng/mL, respectively. He was discharged from the hospital on day 106. Nine months later, he was off medication, became manic again, and was admitted to another psychiatric hospital.