Depressive states are often observed in patients with dementia with Lewy bodies（DLB）during the clinical course and the prodromal stage. In the depressive state in patients with DLB,manifestations such as hallucinations, delusions, anxiety, hypochondria, agitation, and apathy are often found. As the differentiation of DLB and senile depression is often difficult, it is always necessary to consider the possibility of DLB for elderly patients with depression.
 In the pharmacotherapy for the depressive state of DLB,we should avoid using tricyclic antidepressants because of anticholinergic adverse effects. SSRIs and SNRIs are a better choice,with careful monitoring effects and side effects. Modified electro-convulsive therapy （mECT）or transcranial magnetic stimulation therapy（TMS）may be effective for pharmacotherapy-resistant cases.