This study, conducted by G. M. Cherkovich from the Laboratory of Physiology and Pathology of Higher Nervous Activity at the Institute of Experimental Pathology and Therapy in Sukhumi, aimed to induce a neurosis in monkeys by altering their diurnal rhythm. The higher nervous activity of monkeys is complex and resilient to traumatic influences, making it challenging to induce neurosis using standard methods. Previous attempts by D. I. Miminoshvili had success with conflict-based stimuli, but this study focused on diurnal rhythm changes. The experiment involved three monkeys (Bronenosets, Nosorog, and Dog) of the species Papio hamadryas. All monkeys were trained to respond to a simple motor alimentary conditioned reflex with light and a bell as positive signals and a tone as a differential signal. The monkeys were then subjected to an artificial diurnal regime that disrupted their natural rhythm, including alternating between natural and distorted regimes, and eventually to biphasic days (2 "days" and 2 "nights" in 24 hours). This trauma led to the development of neurosis in all three monkeys within two months, characterized by severe derangement of their conditioned reflex activity. Nosorog exhibited excitation, Dog showed inactivity, and Bronenosets displayed a paradoxical phase. The neurosis persisted for several months after the monkeys returned to their normal regime.This study, conducted by G. M. Cherkovich from the Laboratory of Physiology and Pathology of Higher Nervous Activity at the Institute of Experimental Pathology and Therapy in Sukhumi, aimed to induce a neurosis in monkeys by altering their diurnal rhythm. The higher nervous activity of monkeys is complex and resilient to traumatic influences, making it challenging to induce neurosis using standard methods. Previous attempts by D. I. Miminoshvili had success with conflict-based stimuli, but this study focused on diurnal rhythm changes. The experiment involved three monkeys (Bronenosets, Nosorog, and Dog) of the species Papio hamadryas. All monkeys were trained to respond to a simple motor alimentary conditioned reflex with light and a bell as positive signals and a tone as a differential signal. The monkeys were then subjected to an artificial diurnal regime that disrupted their natural rhythm, including alternating between natural and distorted regimes, and eventually to biphasic days (2 "days" and 2 "nights" in 24 hours). This trauma led to the development of neurosis in all three monkeys within two months, characterized by severe derangement of their conditioned reflex activity. Nosorog exhibited excitation, Dog showed inactivity, and Bronenosets displayed a paradoxical phase. The neurosis persisted for several months after the monkeys returned to their normal regime.