PSD and insomnia measurement: 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).