Impairment in active navigation from trauma and Post-Traumatic Stress Disorder.
Altered sleep is a common and central symptom of post-traumatic stress disorder (PTSD). In fact, sleep disturbances are included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic criteria for PTSD. However, it has been hypothesized that sleep disturbances are crucially involved in the aetiology of PTSD, rather than being solely a symptom arising secondarily from this disorder. Therefore, knowing the long-term effects of a trauma can be essential to establish the need of specific interventions for the prevention and treatment of mental disorders that may persist years after a traumatic experience. In one study we showed, for the first time, that even after a period of two years people exposed to a catastrophic disaster such as the L'Aquila earthquake continue to suffer from a reduced sleep quality. Moreover, we observed that sleep quality scores decreased as a function of the proximity to the epicentre, suggesting that the psychological effects of an earthquake may be pervasive and long-lasting. It has been widely shown that disruption of sleep by acute stress may lead to deterioration in memory processing. In fact, in a recent study we observed alterations in spatial memory in PTSD subjects. Our findings indicated that PTSD is accompanied by an impressive deficit in forming a cognitive map of the environment, as well as in sleep-dependent memory consolidation. The fact that this deterioration was correlated to the subjective sleep disturbances in our PTSD group demonstrates the existence of an intimate relationship between sleep, memory consolidation, and stress.