Background: There are conflicting findings about relationship between depression and anger with immunological parameters.
Objective: To investigate the relationship between anger patterns and immune system in depressed patients.
Methods: Thirty-five patients with major depressive disorder were selected according to DSM-IV criteria. The Hamilton Depression Scale and Spielberger Anger questionnaires were used to determine severity of depression and "anger expression pattern", respectively. The control group without a previous history of mental illness was also selected. In the group of patients with moderate depression, serum IgA levels and NK cell percentage were measured.
Results: Mean differences of all types of "anger expression pattern", including; "state-trait anger", "anger expression out", "anger expression in", "anger control out" and "anger control in", between study and control groups, were statistically significant (p<0.05). Difference in mean serum levels of IgA in either group was not significant (p=0.9), but the mean difference was significant in terms of NK-cell percentage in both groups (p=0.04). There was no significant relationship between IgA levels and percentage of NK-cell with all types of "anger expression pattern" in both groups. Only in the control group, IgA had significant correlation with Anger control out (p=0.04).
Conclusion: Moderately depressed patients versus control group had higher Spielberger scores in all types of anger expression pattern except anger controlout and anger control-in. We found no evidence supporting the relationship between" anger expression pattern" and IgA levels and NK cell percentage; however, it seems that depression itself causes reduced number of NK cells and increased IgA levels.