Zolpidem reduces the sleep disturbance of jet lag.

OBJECTIVE: To determine the degree to which zolpidem 10 mg would reduce the sleep disruption associated with rapid, eastward transatlantic travel. BACKGROUND: Subsequent to rapid transmeridian travel, individuals often complain of jet lag which includes transient disturbances in sleep patterns, alertness, appetite and mood. Disturbed sleep and impaired alertness appear to be the most debilitating symptoms of jet lag. METHODS: This multi-center, double-blind randomized, placebo-controlled, parallel-groups study involved 138 adult (mean age 44.9 years) experienced travelers while on their regular eastward transatlantic assignments originating in the US and crossing 5-9 time zones. Subjects were normal sleepers when not traveling and had to have traveled overseas at least twice during the last 24 months. Subjects were randomized to zolpidem 10 mg or placebo for three (optionally four) consecutive nights starting with the first nighttime sleep after travel. Sleep was assessed with daily questionnaires. RESULTS: A total of 130 subjects completed the study. Compared to placebo, zolpidem was associated with significantly improved sleep (statistically significant differences at nights indicated) longer total sleep time (night 1), reduced number of awakenings (nights 1 and 2), and improved sleep quality (nights 1, 2 and 3). Zolpidem was not associated with improvement in sleep latency. No unexpected or serious adverse events were reported and the most common adverse event was headache in both groups (9.2 and 17.6% for placebo and zolpidem, respectively). CONCLUSION: In seasoned travelers, zolpidem 10 mg produced significant improvement in sleep following rapid transmeridian travel.

Work-shift period and weight change.

The present study was done to determine whether weight gain was more prevalent in workers on late shifts than in those on day shifts. A questionnaire about changes in weight, food intake, exercise, and sleep since starting the job on the current shift was given to day-shift and late-shift (evening and night) hospital workers. Data were analyzed for 85 subjects, 36 of whom worked during the day shift and 49 the late shift. The late-shift group reported a mean weight gain of 4.3 kg, which was greater than the mean weight gain of 0.9 kg for the day-shift group (P = 0.02). There were, however, no significant differences in current body mass index (26.7 +/- 5.4 SD) between groups. There was a trend for late-shift workers to report eating more since beginning the later shift (P = 0.06). When combined with those reporting exercising less (P = NS), this trend became significant (P = 0.04). Late-shift workers reported eating fewer meals (1.9 +/- 0.9 SD) than the day-shift workers (2.5 +/- 0.9; P = 0.002). In addition, late-shift workers reported eating the last daily meal later (mean = 22:27, or 10:27 PM) than day-shift workers (17:52 or 5:52 PM; P < 0.00005). Late-shift workers also reported more naps (P = 0.01) and longer naps (P = 0.05) during the work week than did day-shift workers. The reported changes in eating, exercise, and sleep may contribute to the increased weight gain of late-shift workers.

Quality of life in people with insomnia.

OBJECTIVE: To determine whether subjects with insomnia report greater reductions in quality of life (QoL) than subjects without insomnia when assessed with self-report instruments. METHODS: Questionnaires were completed by individuals recruited through media advertisements and screened with a structured telephone interview. Data obtained from 261 individuals with insomnia (INS group) were compared with those of 101 individuals with no sleep complaint, or controls (CTL group). RESULTS: Subjects in the INS group obtained lower mean sum scores on the Medical Outcomes Study Cognitive Scale than did subjects in the CTL group (25.34 +/- 0.34 vs 31.91 +/- 0.58, t = 9.53, p < 0.0001). The INS group also obtained lower mean scores on all subscales of the SF-36 Questionnaire compared with those in the CTL group (each, p < 0.0001 or lower), indicating impairments across multiple QoL domains. Psychiatric assessment revealed that subjects in the INS group obtained significantly higher mean item scores than subjects in the control group on the Zung Depression Scale (2.22 +/- 0.03 vs. 1.52 +/- 0.03, p < 0.0001) and the Zung Anxiety Scale (1.96 +/- 0.02 vs. 1.40 +/- 0.04, p < 0.0001). In addition, subjects in the INS group reported significantly greater impairments in specific QoL domains on the QoL inventory, and the Work and Daily Activities Inventory. No differences were observed between subjects in the INS group who were receiving treatment for insomnia versus those who were untreated. CONCLUSIONS: The results of this study indicate that significant QoL impairments are associated with insomnia.

Postprandial sleep in healthy men.

Twenty-one healthy men between 18 and 30 years of age were studied to determine the effects of midday food intake on sleep. Twelve subjects were administered liquid carbohydrate meals at lunchtime on 2 consecutive days. Subjects slept on 22 of the 24 study days for an average of 93 minutes during 3 hours of postprandial polysomnographic recording. Nine subjects were used as controls and were deprived of a lunch meal. Six of the nine subjects slept for an average of 30 minutes during the postprandial period. This time was significantly shorter than that of subjects in the meal condition (p < 0.005). There was no difference in latency to sleep onset following food intake between the two study groups. The results of this study suggest that lunchtime food intake does not promote the initiation of sleep, but that it does increase the duration of sleep episodes occurring during the postprandial period.

The relationship between daytime and nighttime food intake in an obese night-eater.

Some obese individuals consume food during awakenings from nighttime sleep. Three studies were conducted on a 28-year-old morbidly obese male with chronic sleeping complaints and insignificant weight loss, despite self-reported daily caloric restriction: I. For 3 mo, the subject recorded food intake for 24-h periods. Mean daytime intake was 1286 kcal +/- 386 (SD), and mean nighttime intake was 1036 kcal +/- 487 (SD). Caloric values of daytime and nighttime intake were negatively correlated, r = -0.22, df= 82, p < .05. II. Seven consecutive 24-h food intake recordings were obtained with an automated formula dispenser when the subject was an inpatient on a metabolic ward and received ad libitum formula as his sole food source. Mean daytime intake was 1245 +/- 662 (SD), and mean nighttime intake was 231 +/- 236 (SD). There was a non-significant negative correlation between daytime and nighttime intake, r = -0.32, df = 5, NS. III. The subject underwent polysomnographic studies on 2 non-consecutive nights, following the administration of either a low (600 kcal) or high (1800 kcal) daytime caloric condition. The subject, upon awakening from nighttime sleep, could eat from a platter of sandwich quarters placed at his bedside. The addition of 1200 kcal to daytime intake decreased nighttime intake by 654 kcal, or by 55% of the additional calories delivered during the day. The three studies (I, II, and III) show that daytime food intake can be negatively correlated with nighttime intake, and that daytime intake can influence nighttime intake in a documented obese night-eater.

Postprandial sleep and thermogenesis in normal men.

Twelve normal male subjects were given low- (16.77 kj/kg) and high- (54.49 kj/kg) calorie liquid carbohydrate lunch meals on 4 days, during which measures of sleep EEG, thermogenesis (heat production), core body temperature, and skin surface temperature were obtained. On 2 days subjects were required to remain awake, and on 2 days sleep was allowed. Both meals were administered in each condition. On the days that subjects were instructed to remain awake, thermogenesis was significantly greater following high-calorie meals than low-calorie meals, and both meal conditions produced levels of thermogenesis that were greater than those observed when sleep was allowed. When given the opportunity, 11 of 12 subjects slept following both low- and high-calorie meals. There was no difference between meal conditions in the total minutes or percent of stages 1, 2, 3/4, or rapid eye movement (REM) sleep following meals. However, the onset of postprandial sleep episodes was associated with the peak of the postprandial rise in thermogenesis, and the occurrence of sleep was followed by precipitous and statistically significant declines in thermogenesis and core body temperature, as well as increases in skin surface temperature. These data suggest that postprandial sleep is associated with rises in thermogenesis, and that its occurrence decreases postprandial heat production and body temperature.

Trait-state artifacts and the diagnosis of personality disorders.

The multiaxial nature of DSM-III has stimulated interest in the personality disorders. There are also indications that it has produced an increase in their diagnosis. However, there is clinical and psychometric evidence that a personality evaluation undertaken while a patient is in a dysphoric mental state may distort or misrepresent traits, the so-called trait-state problem in personality assessment. The present study appears to be the first to investigate this phenomenon with a clinical interview rather than with personality tests. It examined the effect of anxiety, depression, and level of global impairment on the diagnosis of personality disorder and the assessment of the criteria for the individual Axis II disorders. Eighty-four patients, most of whom had current Axis I diagnoses, were evaluated by seven experienced clinicians with a new semistructured interview, the Personality Disorder Examination. The sample evidenced a trend toward acknowledging fewer maladaptive personality traits at follow-up than at entry. There was no evidence, however, that anxiety or depression had affected either the diagnosis of a personality disorder or the criteria associated with most of the individual personality disorders.

Early onset and accumulation of REM sleep in depression: a study of the phase-advance hypothesis.

Twenty-two depressed subjects who met criteria for major depressive disorder were grouped according to their initial REM latency. Subjects with short (less than or equal to 60 min) initial REM latency were separated from those with normal (greater than 60 min) initial REM latency. Subjects with short initial REM latency were found to have earlier onsets to at least two subsequent REM periods. The number of minutes of REM sleep accumulated were also plotted against elapsed time after sleep onset. The short-latency group accumulated REM sleep earlier than, but at about the same rate as, the normal latency group. These data support the phase-advance hypothesis of REM sleep in depression.

Subjective ratings of the characteristics and sequelae of good and poor sleep in normals.

Forty normal subjects completed a general screening inventory and two post-sleep questionnaires (PSQs). One PSQ was self-administered after a good night of sleep and one after a poor night of sleep. Responses to a subset of items from both nights were factor-analyzed. Varimax rotation yielded four factors that were interpreted as (a) Dysphoria (b) Cognitive Inefficiency and Sleepiness (c) Motor Impairment and (d) Social Discomfort. Night-to-night comparisons of subjects' estimates of sleep parameters reveal that poor sleep is associated with longer sleep latency, a greater number of awakenings, less total sleep time, and more difficulty initiating and maintaining sleep than good sleep. Mean scores for each generated factor of the PSQ also differed significantly between nights, suggesting that a greater degree of disturbance is associated with poor sleep. The implications of these data as well as the reliability of subjective ratings of sleep quality and post-sleep experiences are discussed.

Effects of age on auditory awakening thresholds.

Auditory awakening thresholds ( AATs ) were assessed in sleeping men and women at three age levels (18 to 25, 40 to 48, and 52 to 71 years) with a procedure that employed a 5-sec tone in accordance with the up-and-down method. Although age was less influential than individual differences in predicting AAT levels, there was a significant and substantial AAT decline from early adulthood to later life in Sleep Stages 4, 2, and REM. With no variation by sex, this progressive decline was apparent by the 40s in Stages 4 and 2 and was sharpest from one age level to another in Stage 4. Decline was more gradual and delayed in REM, probably because of a sampling artifact based on stimulus incorporation in dreams. These findings help to explain increased sleep disturbance in the later years as a result of diminished intensity of sleep, which makes sleep more difficult to sustain.