Plasma magnesium level and psychomotor retardation in major depressed patients

Numerous studies have been performed on magnesium (Mg) metabolism in patients with mood disorders but consistent results have not been obtained. To date, systematic clinical data about Mg levels in major depressed patients according to the psychopathological profile are not available. In the present study we have investigated the relationship between plasma Mg level severity of symptoms and specific psychopathological dimensions (anhedonia and retardation) in 53 mild-to-moderately depressed patients (M/F = 21/32; mean age 46.49 +/- 13.48). The psychopathological status was assessed using standard psychometric evaluation scales: HAM-D for severity of depression, HAM-A for severity of anxiety symptoms, DRRS for psychomotor retardation and SHAPS for anhedonia. We did not find any significant correlation between total plasma Mg levels (0.86 +/- 0.09 mmol/L), severity of depression (HAM-D = 17.13 +/- 6.76) and anxiety (HAM-A = 16.62 +/- 6.60). A statistically significant correlation between Mg levels and psychomotor retardation was observed. Patients with higher psychomotor retardation scores (DRRS = 20.41 +/- 7.72) showed higher plasma Mg levels (0.89 +/- 0.07 mmol/L), even though they remained in the normal range, in comparison to patients with lower retardation scores (DRRS = 7.29 +/- 3.80; Mg = 0.82 +/- 0.10 mmol/L). A relationship between catecholamines and Mg metabolism has been described and our results support the hypothesis that hypermagnesaemia might lead to hypoactivity and psychomotor retardation which is so often observed in depressed patients.