Background: a growing body of evidence (including clinical investigations) suggests that the alterations of blood zinc level could be a potential marker of depression.
Aim of the study: to assess if the serum zinc is a state or trait marker of depression and drug resistance.
Methods: a group of thirty, 18–55-year old, unipolar depressed patients fulfilling the ICD-10 criteria for a moderate or severe depressive episode without psychotic symptoms was recruited. After a one week washout period patients were treated with imipramine (100–200 mg daily) for 12 weeks. Serum zinc level and patient’s psychological status were assessed four times: the day before the washout and 2, 6, and 12 weeks after the commencement of the treatment. Patient’s serum zinc was compared to a group of 25 healthy volunteers.
Results: Serum zinc level was significantly lower in acute depressed patients than in healthy volunteers but there was no significant correlation between serum zinc and severity of depression measured by BDI or HADRS. At the end of the study, there were significant differences in zinc values between therapy responders and non-responders and between remitters and non-remitters. Serum zinc in treatment responders and in remitters significantly rose and reached the level comparable to the healthy control group.
Conclusions: Serum zinc is a state marker of depression. There are no relationships between serum zinc and severity of depression.