In 2005, the serum and CSF autoantibody against a protein termed EFA6A (that interacts with potassium channels) was reported to be associated with a paraneoplastic encephalitis associated with a depressive syndrome, incoherent thoughts, insomnia, panic, personality changes and psychotic symptoms such as delusional thinking and auditory hallucinations (Vitaliani et al. 2005) (Fig. 1). Here, PSD is linked to depressive disorder.