Their conclusion was that all drugs that produce large and sustained decrements of REMS time and were followed by a REMS rebound upon withdrawal are active on endogenous depression. Treatment by antidepressant drugs- and also by (partial, REMS-specific; or full) sleep deprivation, electronconvulsive treatment, or psychotherapy-would parallel or act through the reversal of the abnormal characteristics observed in the sleep of depressed patients. Whatever the underlying mechanism, RL is shortened during depression

and should be prolonged; REMS Inhibitors,research,lifescience,medical percentage is higher during depression and should be reduced. It appears, however, that the general rule of REMSreducing, RL-lengthening efficient antidepressants suffers many exceptions, because several efficient drugs do not reduce REMS (Table I). Therefore, either more than one mechanism is at work and only a fraction of the antidepressants comply with the rule, or sleep modifications during treatment are only Inhibitors,research,lifescience,medical indirectly linked to efficiency against depression. Furthermore, the degree to which REMS is suppressed and the time where the suppression occurs do not in general correspond to clinical improvement (except

for MAOIs). Summary of theories Although sleep and the Inhibitors,research,lifescience,medical neurophysiological mechanisms that determine it are likely to be very close to the mechanisms that define depression, they are most probably not this website identical and we certainly cannot claim that sleep ought to be corrected (REMS reduced, RL prolonged, SWS/delta sleep increased, better continuity) in order for depression to be relieved. Sleep is not a mere epiphenomenon, as testified by the frequent Inhibitors,research,lifescience,medical association with insomnia, the efficiency of sleep manipulations on depression, and the modifications induced by antidepressant drugs, but it is probably not a necessary component of the mechanisms of depression. Conclusions More than 30 years of sleep research in the domain of depression and other psychiatric disorders have yielded many interesting results.

On the other Inhibitors,research,lifescience,medical hand, several deadend alleys have been explored, following promising concepts and generating some frustration. We are still missing a global and comprehensive theory to explain what is observed, both at baseline and after some time of treatment. This should be considered in the context of the huge complexity of the issues. To start with, the else functions of sleep itself are still very poorly understood (see reference 67 for a recent overview on the issue), so that we hardly can tell how much sleep or what kind of sleep is recommended for a given person. The distinction between REMS and non-REMS implies another level of complexity that is not yet resolved. Depression is currently regarded as part of a spectrum of disorders, ranging from anxiety to psychosis.