Memory circuits of the brain are activated by self-generated brain waves, primarily during sleep. These activations refresh the efficacies (strengths) of synapses in affected circuits, maintaining the efficacies at the "dedicated" values that support circuit functions. The neural pathologies underlying many mental disorders appear to exert their deleterious influences by inducing abnormalities in brain waves. The abnormal waves, in turn, fail to sustain dedicated synaptic efficacies in memory circuits, leading to mental malfunction. Dreaming is an "unconscious" awareness of circuit reinforcement during sleep, with dream contents being derived from the activated circuits. When synaptic efficacies are degraded, the dreams are illusory.