Current concepts of autoantibodies in mood disorders

Abstract Research into the causes of mood disorders has been going on for decades. However, most of the hypotheses put forward have been insufficiently substantiated by living biomarkers. Much research is therefore being conducted into biomarkers that help us better assess the diagnosis and course of mood disorders. Neural autoantibodies are one such biomarker potentially appearing in a subgroup of mood disorders. The aim of this narrative review is to describe the spectrum of autoantibodies in mood disorders while substantiating their prevalence, about which there is very inconsistent evidence. In addition, we discuss autoantibodies in the context of systemic autoimmune diseases associated with depressive symptoms. The pathogenicity of individual autoantibodies has occasionally been demonstrated in animal models, and there is evidence that the severity of depressive symptoms correlates with certain autoantibodies. Possible models of autoimmunity are also explained, such as involvement of the B-cell system, the complement system, and systemic inflammation in autoimmune processes. Nevertheless, note that the mere presence of autoantibodies does not justify the assumption of an autoimmune genesis, as more evidence is needed. The aim of this review is to describe the concepts behind targeting autoantibodies in mood disorders.