Effects of acute, subacute, and chronic sleep deprivation on self-injury–like behavior in adolescent rats

Self-injurious behavior (SIB) is associated with dysregulation of monoaminergic systems and heightened impulsivity, both of which are strongly influenced by sleep. Adolescence represents a neurodevelopmental period of increased vulnerability to sleep loss. The present study investigated the effects of acute sleep deprivation (24 h; ASD-24 h), subacute sleep deprivation (48 h; SASD-48 h), and chronic sleep deprivation (72 h; CSD-72 h) on self-injury-like behavior (SILB) in adolescent rats. Male Wistar rats underwent SD using the multiple-platform method and were monitored for SILB at 4-hour intervals over seven days following SD. The severity of SILB was manually scored using a scoring table by an experimenter who monitored the animals' behavior. Time and group differences were assessed by statistical analysis of variance. Body weight was also measured to evaluate physiological effects of SD. All SD paradigms elicited significantly elevated SILB scores compared to controls over the seven-day post-deprivation period (P < 0.001). CSD-72 h produced the highest cumulative SILB burden, as reflected by the largest area under the curve (AUC). Although SILB scores remained below the severe injury threshold (score < 3), moderate self-injury was consistently increased in all sleep-deprived groups. These results indicate that sleep loss induces sustained, duration-dependent elevations in SILB in adolescent rats. While the underlying neural mechanisms were not directly assessed, the findings suggest that prolonged sleep deprivation may disrupt neurobiological systems regulating self-directed behaviors, highlighting the need for further mechanistic studies.