Objective We investigated the psychiatric disorders in subacute myelo-optico-neuropathy (SMON) patients by structured interview. The prevalence of major depressive disorder in SMON patients was estimated by structured interview and using Beck's depression inventory (BDI) questionnaires.
Materials and Methods Psychiatric conditions were evaluated in 26 SMON patients (9 males, 17 females, mean age 70.7 years) living in Kyoto prefecture through a structured interview given by psychiatrists. BDI questionnaires and clinical symptoms of SMON were investigated in 106 patients, ranging from 51 to 91 years in age (mean, 73.5) with SMON patients living in Kinki area. BDI questionnaires were obtained from 92 age-matched aged healthy people, ranging from 57 to 91 years in age (mean, 75.8), living in Kyoto city.
Results Among the psychiatric disorders in SMON patients, the prevalence of major depressive disorder and suicidal ideation significantly increased during the period of clioquinol intake and four patients (15.4%) out of 26 SMON patients still suffer from major depressive disorder. The prevalence of major depressive disorder in SMON patients was estimated at 15.1% (16/106) and this percentage was about seven times as frequent as in the age-matched aged healthy people (2.2%; 2/92). In female SMON patients, the degree of the depressive states was significantly correlated with the severe degree of dysesthesia of the lower extremities, and it was inversely correlated with the duration of SMON disease and the total scores of the Barthel index.
Conclusion This is the first report that shows the prevalence of major depressive disorder in SMON patients at present, which was seven times more frequent than age-matched aged healthy persons.