Stress perçu et santé physique des doctorants dans les universités françaises

Few studies have focused on PhD students in France despite the fact that this population appears to be particularly vulnerable to stress and often faces precariousness. This research investigated associations between socio-demographic factors, health behaviours, perceived stress and physical health in a wide sample of PhD students (n = 1923) in order to have a better understanding of this population's specificities. Our results indicated that stress is a critical issue among PhD candidates. Predictors of perceived stress were: gender, age, satisfaction with supervision, sleep quality and sports practice. Findings from this study confirm the relevance of the transactional model to investigate students’ health issues and suggest that physical activity and stress management should be encouraged through health promotion programs.     

Sleep deprivation impairs object recognition in mice

Many studies in animals and humans suggest that sleep facilitates learning, memory consolidation, and retrieval. Moreover, sleep deprivation (SD) incurred after learning, impaired memory in humans, mice, rats, and hamsters. We investigated the importance of sleep and its timing in an object recognition task in OF1 mice subjected to 6h SD either immediately after the acquisition phase (0-6 SD) or 6h later (7-12 SD), and in corresponding undisturbed controls. Motor activity was continuously recorded with infrared sensors. All groups explored two familiar, previously encountered objects to a similar extent, both at the end of the acquisition phase and 24h later during the test phase, indicating intact familiarity detection. During the test phase 0-6 SD mice failed to discriminate between the single novel and the two familiar objects. In contrast, the 7-12 SD group and the two control groups explored the novel object significantly longer than the two familiar objects. Plasma corticosterone levels determined after SD did not differ from time-matched undisturbed controls, but were significantly below the level measured after learning alone. ACTH did not differ between the groups. Therefore, it is unlikely that stress contributed to the memory impairment. We conclude that the loss of sleep and the activities the mice engaged in during the SD, impaired recognition memory retrieval, when they occurred immediately after acquisition. The delayed SD enabled memory consolidation during the 6h when the mice were allowed to sleep, and had no detrimental effect on memory. Neither SD schedule impaired object familiarity processing, suggesting that only specific cognitive abilities were sensitive to the intervention. Sleep may either actively promote memory formation, or alternatively, sleep may provide optimal conditions of non-interference for consolidation.     

Cognitive-behavioral therapy of insomnia: A clinical case series study of patients with co-morbid disorders and using hypnotic medications

Cognitive-behavioral therapy for insomnia (CBTi) has demonstrated considerable efficacy within randomized clinical trials and case-series designs. This case-series study in a community sleep medicine clinic assessed the effectiveness of an eight-session CBTi protocol chronic insomnia patients who were allowed to continue their use of hypnotics (intent-to-treat n = 48), administered by a clinical psychology doctoral student receiving training and supervision in CBTi by a behavioral sleep medicine certified clinician. Outcome measures included daily sleep diaries, self-report measures on insomnia severity, dysfunctional beliefs and attitudes about sleep, daytime sleepiness, as well as medication usage. Patients showed significant improvements in sleep onset latency, wake time after sleep onset, sleep efficiency, insomnia severity, and dysfunctional sleep beliefs from pre- to post-treatment. No changes were seen in daytime sleepiness - patients were not excessively sleepy either before or after treatment. Use of sleep medication declined significantly from 87.5% pre-treatment to 54% post-treatment, despite no active efforts to encourage patients to withdraw. Results demonstrate that a CBTi conducted in a community sleep medicine clinic with patients not required to discontinue sleep-related medications can have similar effects as therapy delivered among those not on medication.     

Are delusional contents replayed during dreams?

The relationship between dream content and waking life experiences remains difficult to decipher. However, some neurobiological findings suggest that dreaming can, at least in part, be considered epiphenomenal to ongoing memory consolidation processes in sleep. Both abnormalities in sleep architecture and impairment in memory consolidation mechanisms are thought to be involved in the development of psychosis. The objective of this study was to assess the continuity between delusional contents and dreams in acutely psychotic patients. Ten patients with a single fixed and recurring delusional content were asked to report their dreams during an acute psychotic break. Sixteen judges with four different levels of acquaintance to the specific content of the patients’ delusions were asked to group the dreams, expecting that fragments of the delusional thought would guide the task. A mathematical index (f, t) was developed in order to compare correct groupings between the four groups of judges. Most judges grouped the dreams slightly above chance level and no relevant differences could be found between the four groups [F(3, 12) = 1.297; p = n.s.]. Scoring of dreams for specific delusional themes suggested a continuity in terms of dream and waking mentation for two contents (Grandiosity and Religion). These findings seem to suggest that at least some delusional contents recur within patients’ dreams. Future studies will need to determine whether such continuity reflects ongoing consolidation processes that are relevant to current theories of delusion formation and stabilization.     

Poorer sleep quality is associated with lower emotion-regulation ability in a laboratory paradigm

Theoretical models suggest a positive relationship between sleep quality and individuals' ability to regulate emotion. However, few studies have empirically tested this hypothesised link using standardised laboratory measures of emotion-regulation ability. The present research examined the relationship between sleep quality and the ability to implement a type of emotion regulation that has particularly important implications for psychological health: cognitive reappraisal (cognitively reframing an emotional event so as to dampen its impact). To do so, 156 participants (86 male) reported on their past week's sleep quality. Their ability to implement cognitive reappraisal (CRA) was then measured with a standardised laboratory challenge. Participants with poorer self-reported sleep quality exhibited lower CRA, even after controlling for fourteen potential key confounds (e.g., age, negative affect, mood disorder symptoms, stress). This finding is consistent with the idea that poorer sleep quality impairs individuals' ability to engage in the crucial task of regulating negative emotions.