The reexperiencing ofa traumatic event in the form of repetitive dreams, memories, or flashbacks is one of the cardinal manifestations of posttraumatic stress disorder (PTSD). The dream disturbance associated with PTSD may be relatively specific for this disorder, and dysfunctional REM sleep mechanisms may be involved in the pathogenesis of the posttraumatic anxiety dream. Furthermore, the results of neurophysiological studies in animals suggest that CNS processes generating REM sleep may participate in the control of the classical startle response, which may be akin to the startle behavior commonly described in PTSD patients. Speculating that PTSD may be fundamentally a disorder of REM sleep mechanisms, the authors suggest several strategies for future research. (Am J Psychiatry 1989; 146:697-707)

Sleep Disturbance as the Hallmark of Posttraumatic Stress Disorder

Normal Sleep Patterns (1) Two kinds ojsleep It is generally recognised that there are two qualitatively different kinds of sleep which alternate throughout the night in normal healthy individuals. These are the non-rapid eye-movement (NREM) sleep or orthodox sleep and the rapid-eye-movement (REM) sleep or paradoxical sleep. By means of electro encephalography (EEG), electrooculography (EOG) and electromyography (EMG), different stages of sleep have been defined according to a standardized scoring system (Rechtschaffen and Kales, 1968). NREM sleep is further classified into stages 1, 2, 3 and 4, which show a graded decrease in autonomic activities and an increase in depth of sleep. Stage 4 sleep is therefore the deepest stage and together with stage 3 is often referred to collectively as slow-wave sleep (SWS). Characteristically the first appearance of SWS after the onset of sleep nearly always coincides with a surge of growth hormone level in the blood. On the other hand, REM sleep is characterized by bursts of rapid eye movements (or REM activity), abolition of tone in many skeletal muscles, heightened but variable autonomic activities, and a low-voltage mixed frequency EEG pattern resembling that of stage 1 sleep. In animals, spike discharges can be recorded in the regions of pons, lateral geniculate nucleus and occipital cortex (PGO spikes) just pre ceding or during REM sleep. When a subject is awakened from REM sleep, he often reports dreams charged with emotions, in contrast to reports of mental activity obtained from most NREM awakenings which have the quality of thoughts. Under normal circumstances adult indivi duals sleep from 7 to 8 hours each night, 20â€”25 per cent of which will be spent in REM sleep. A normal night's sleep usually begins with NREM sleep, from light to deep stages, which is interrupted about every 90 minutes by a period of REM sleep. Thus NREMâ€”REM sleep cycles alternate throughout the night, and there are 4â€”6such sleep cycles each night. In general, NREM sleep tends to predominate in the beginning of the night, whilst the REM sleep period becomes more prolonged as the night progresses.

Sleep, depression and antidepressants.

The fundamental issue underlying the question of predicting treatment outcome with lithium is whether there are meaningful subgroups within the broad spectrum of patients with affective disorders. A pessimistic view of our progress in resolving this question would be that we have not progressed in our collective research efforts beyond the point reached by Cade 1 30 years ago and by Schou 2 20 years ago. Many clinicians have discussed the use of drugs to identify specific disorders "hidden" within broad diagnostic categories: the examples of penicillin in cerebral syphilis, and of cyanocobalamin in pernicious anemia are often cited to support this approach. For our purposes, the major limitation of these analogies is that cerebral syphilis and pernicious anemia rarely show spontaneous remissions, whereas the affective disorders usually do. So these analogies are not entirely apt: when dealing with the affective disorders, we are faced with much more difficult methodological

Prediction of treatment outcome with lithium.

The effect of lithium on slow wave sleep (SWS) was studied in ten normal male volunteers using home based cassette sleep recording and automatic sleep stage analysis. Lithium increased SWS, an effect consisten with a reduction in brain 5-HT2 receptor function.

D.A. Chernik

Papers

Effects of lithium carbonate on sleep.