Two types of insomnia: too much waking or not enough sleep

Neuropsychiatric effects of caffeine

Psychiatrists rarely enquire about caffeine intake when assessing patients. This may lead to a failure to identify caffeine-related problems and offer appropriate interventions. Excessive caffeine ingestion leads to symptoms that overlap with those of many psychiatric disorders. Caffeine is implicated in the exacerbation of anxiety and sleep disorders, and people with eating disorders often misuse it. It antagonises adenosine receptors, which may potentiate dopaminergic activity and exacerbate psychosis. In psychiatric in-patients, caffeine has been found to increase anxiety, hostility and psychotic symptoms. Assessment of caffeine intake should form part of routine psychiatric assessment and should be carried out before prescribing hypnotics. Gradual reduction in intake or gradual substitution with caffeine-free alternatives is probably preferable to abrupt cessation. Decaffeinated beverages should be provided on psychiatric wards.

Effect of caffeine-free beverages on elderly hospitalised patients

The objectives of the study were to determine whether, by providing caffeine-free tea and coffee, plasma caffeine concentrations would fall in elderly hospitalised patients, and whether, as a result, sleep profiles and urinary incontinence would be altered.

Twenty-eight patients in two wards of an elderly care hospital received caffeine-containing or caffeine-free tea and coffee for consecutive three week periods in a study which was blinded to patients, nurses and investigator. Median caffeine concentration (μg/ml) was stable between the run in period at 2.3 (range 0–5.8) and the caffeine-containing period at 1.6 (range 0.4–6.0), but fell significantly to 0 (range 0–0.7), during the caffeine-free period (P<0.001). In spite of significantly lowered caffeine concentrations, no change in sleep patterns or urinary incontinence was noted. Of 12 patients with sleep problems a benefit to sleep quality was reported by two individuals, one of whom was prescribed hypnotics from which she subsequently successfully withdrew.

Effects of caffeine on human behavior

The literature suggests that the following effects on behavior of adult humans may occur when individuals consume moderate amounts of caffeine. (1) Caffeine increases alertness and reduces fatigue. This may be especially important in low arousal situations (e.g. working at night). (2) Caffeine improves performance on vigilance tasks and simple tasks that require sustained response. Again, these effects are often clearest when alertness is reduced, although there is evidence that benefits may still occur when the person is unimpaired. (3) Effects on more complex tasks are difficult to assess and probably involve interactions between the caffeine and other variables which increase alertness (e.g. personality and time of day). (4) In contrast to the effects of caffeine consumption, withdrawal of caffeine has few effects on performance. There is often an increase in negative mood following withdrawal of caffeine, but such effects may largely reflect the expectancies of the volunteers and the failure to conduct "blind" studies. (5) Regular caffeine usage appears to be beneficial, with higher users having better mental functioning. (6) Most people are very good at controlling their caffeine consumption to maximise the above positive effects. For example, the pattern of consumption over the day shows that caffeine is often consumed to increase alertness. Indeed, many people do not consume much caffeine later in the day since it is important not to be alert when one goes to sleep. In contrast to effects found from normal caffeine intake, there are reports that have demonstrated negative effects when very large amounts are given or sensitive groups (e.g. patients with anxiety disorders) were studied. In this context caffeine has been shown to increase anxiety and impair sleep. There is also some evidence that fine motor control may be impaired as a function of the increase in anxiety. Overall, the global picture that emerges depends on whether one focuses on effects that are likely to be present when caffeine is consumed in moderation by the majority of the population or on the effects found in extreme conditions. The evidence clearly shows that levels of caffeine consumed by most people have largely positive effects on behavior. Excessive consumption can lead to problems, especially in sensitive individuals.

Psychiatric morbidity in a Nigerian paediatric primary care service: a comparison of two screening instruments

We evaluated the screening properties of the Children's Behaviour Questionnaire (CBQ) and the Reporting Questionnaire for Children (RQC) in an urban primary care setting in Nigeria. Using various validity indices and the results of Receiver Operating Characteristic analysis, we showed that the two instruments had identical abilities at differentiating children with specific psychiatric disorders from those without. The cut-off threshold for the CBQ in this setting was different from what is commonly reported elsewhere. While the CBQ was able to differentiate between conduct and emotional disorders, the RQC had the advantage of relative brevity.

The intrasleep relationship between wake and stage 4 examined by transition probability analysis

The relationship between wake and stage 4 of slow-wave sleep (SWS), in particular the previously observed deficiency in SWS accompanying sleep containing long-wake periods, is examined in this study of 147 health subjects. Stage shift comportment is compared between those NREM/REM cycles with wake periods greater than 3 minutes and those with less, using the method of transition probabilities. It is shown that these long wake interruptions occur preferentially in light sleep, and systematically disrupt the regular normal descent towards SWS, but do not significantly reduce the number of SWS episodes. There is at the same time, however, a reduction in the average duration of stage 4 periods of SWS which accounts for the observed reduction in the total amount of SWS.

Duration of EEG sleep stages in different types of disturbed night sleep

The duration of each episode of any one electrophysiological sleep stage or any episode of intervening wakefulness was determined in three kinds of disturbed sleep, namely, in naturally impaired sleep of late middle-aged, normal people, in sleep after caffeine administration, and in sleep after hypnotic drug withdrawal.

When compared with the sleep of young people, the sleep of late middle-aged subjects was characterized by an increase in longer episodes of intervening wakefulness plus drowsiness, and by a decrease in longer episodes of sleep stages 3 + 4 and REM. The sleep after caffeine, compared with the baseline sleep, contained an increased proportion of longer episodes of intervening wakefulness plus drowsiness but no significant change in the episode duration of any of the sleep stages. In the case of the drug withdrawal sleep, compared with the sleep on hypnotic drug, there was no change in the episode duration of intervening wakefulness plus drowsiness but there was a significant shortening of episode duration for sleep stages 2 and 3+4, with a similar trend for REM sleep episodes.

Thus a sleep disturbance might be characterized by increased stability of wakefulness, by decreased stability of sleep or both. Different types of sleep disturbance might require different types of treatment.

The number and duration of the episodes of the various EEG stages of sleep in young and older people

Episodes of any one electrophysiological sleep stage and of intervening wakefulness were examined as to their numbers and durations in sleep of ten young normal subjects (mean age 22) and in significantly more disturbed sleep of fourteen late middle age normal people (mean age 55). No significant difference between the two age groups was found for any of the stages in the mean number of episodes taken from 4 nights. For any of the stages, the individual numbers of episodes accumulated over the 4 nights varied in a wide range and showed significant consistency with similar data obtained in another set of 4 nights. There were significant differences between the two age groups in episode duration. The sleep of the older group contained significantly higher proportions of longer episodes of wakefulness and drowsiness and significantly lower proportions of longer episodes of slow wave sleep and REM sleep. Thus, the initiation of episodes of EEG stages was on average similar in the better sleep of young and impaired sleep of older subjects, but the maintaining or termination of the episodes were different.