Correlation between serum and urinary calcium levels and psychopathology in patients with affective disorders

To examine whether serum and urinary calcium levels were related to the psychopathology index (i.e. average score in clinically relevant scales of Minnesota Multiphasic Personality Inventory), 24 women aged 35.6 plus or minus 2.5 years and 20 men aged 34.3 plus or minus 2.1 years, suffering from affective disorders, were studied. A non-parametric bivariate correlation analysis revealed a negative correlation between PI and serum calcium (r = -0.256, p < 0.01), while urinary calcium levels correlated positively with PI (r = 0.236, p < 0.02). A positive correlation occurred between serum and urinary calcium (r = 0.968, p < 0.0001). When the data were analyzed by categorical classification of patients with normal or abnormal PI scores, serum calcium levels were smaller, and urinary calcium levels higher, in patients with abnormal PI (p < 0.01). The results support to the concept that alterations of calcium homeostasis occur in psychopathology.