Theories for ECT’s efficacy include: ‘psychological, neurophysiological, neurochemical, neuroendocrine and neuropeptide mechanisms’ but ‘there is no single theory that satisfactorily explains the mechanism of action of ECT in various psychiatric illnesses’ (Grover et al 2005). At first there were psychoanalytic theories, including fear theory, regression theory and punishment theory, and non-psychoanalytic theories, such as brain damage theory and amnesic theory.