[Erythrocyte mean corpuscular volume of psychiatric patients].

It has been observed clinically that the mean corpuscular volume (MCV) of erythrocytes is increased in psychiatric patients, but this phenomenon has not been investigated. We therefore compared the MCV of 177 patients in our psychiatric day care ward and in our psychiatric outpatient clinic. The MCV of these psychiatric patients, and especially that of the outpatients, were significantly greater than that of normal controls. No association was found between MCV and sociodemographic or clinical variables. The sensitivity of a high MCV level as a diagnostic for folic acid deficiency was 42.9%, with a specificity of 80.6%. The sensitivity of a high MCV level as a diagnostic for vitamin B12 deficiency was 23.1%, with a specificity of 79.4%.