Daily rhythms of the sleep-wake cycle

The amount and timing of sleep and sleep architecture (sleep stages) are determined by several factors, important among which are the environment, circadian rhythms and time awake. Separating the roles played by these factors requires specific protocols, including the constant routine and altered sleep-wake schedules. Results from such protocols have led to the discovery of the factors that determine the amounts and distribution of slow wave and rapid eye movement sleep as well as to the development of models to determine the amount and timing of sleep. One successful model postulates two processes. The first is process S, which is due to sleep pressure (and increases with time awake) and is attributed to a 'sleep homeostat'. Process S reverses during slow wave sleep (when it is called process S'). The second is process C, which shows a daily rhythm that is parallel to the rhythm of core temperature. Processes S and C combine approximately additively to determine the times of sleep onset and waking. The model has proved useful in describing normal sleep in adults. Current work aims to identify the detailed nature of processes S and C. The model can also be applied to circumstances when the sleep-wake cycle is different from the norm in some way. These circumstances include: those who are poor sleepers or short sleepers; the role an individual's chronotype (a measure of how the timing of the individual's preferred sleep-wake cycle compares with the average for a population); and changes in the sleep-wake cycle with age, particularly in adolescence and aging, since individuals tend to prefer to go to sleep later during adolescence and earlier in old age. In all circumstances, the evidence that sleep times and architecture are altered and the possible causes of these changes (including altered S, S' and C processes) are examined

Multicentre rating of a delusional patient with help of the AMDP scale

A videotaped interview of a delusional patient was evaluated by 33 French, Swiss and Belgian raters. The inverse factor analysis of the raters and multivariate indexes demonstrate in this single case study that the interrater reliability depends on: a) the general training of the raters in psychopathology; b) their knowledge of the AMDP System; c) a comprehensive understanding of the psychopathology of the patient; d) AMDP concepts; e) the interview technique (this latter deficiency may be corrected by a semi-structured interview

Short history of mixed states

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Comment le praticien doit-il interpréter les résultats d’un essai clinique ?

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[Pathophysiological models of mixed states].

International audienceMixed states are complex manifestations of bipolar disorders. Pathophysiology of mixed states remains unclear. Several models have been proposed to understand the mechanisms underlying these mood states. These models describe mixed state either as a combinaison of depression and mania, as well as a transition between mania and depression, or mixed state as a severe type of depression or mania. Pathophysiological hypotheses involve temperaments or some personality disorders, psychiatric comorbidities as well as substance use disorders, or thyroid dysfunction. However, the formal demonstration of any specific genetic vulnerability to mixed state has not yet been provided