Folk wisdom suggests that chicken extract is useful for recovery from physical and mental fatigue. To explore this question, the physiological effect of Brand's Essence of Chicken (BEC), a popular chicken extract used as a traditional remedy, was assessed during recovering from mental stress. We quantitated the blood levels of stress-related substances, and examined the task performance and subjects' mood states during mental workloads. Subjects were 20, healthy male students who have never tasted BEC. They took two bottles of BEC or a placebo (70 ml/bottle) daily in the morning for 7 days. On the final experimental day, two mental workload tests were performed: (A) a mental arithmetic test (MAT; 1600 trials of two or three figure-addition or subtraction for 40 min). (B) a short-term memory test (SMT; 20 trials of memorizing 9 digit numbers). Blood was collected before and after each workload task. After the mental workload, the recovery of mean cortisol level of subjects who consumed BEC was significantly faster than that for those consuming the placebo. The task performance of subjects performing the MAT and SMT was also improved with BEC consumption compared with placebo. According to the profile of mood state questionnaire, subjects felt more active and less fatigued during the workload when they took BEC regularly. We conclude that the extract of chicken has the potential to metabolize stress-related substance in blood and to promote recovery from mental fatigue.

The Morningness-Eveningness (ME) scores and body temperature readings were collected from 25 students to assess the validity of Japanese version of Horne-Östberg's ME questionnaire. Significant differences between morning and evening types were found for acrophase (peak time) of body temperature, and ME score was significantly correlated with peak time of body temperature. These results suggest that the Japanese version of the questionnaire was valid.

This article is a survey study, followed by an experimental study, examining the differences of sleep-wake habits and sleep electroencephalographic (EEG) variables between morning and evening type subjects (Ss). In the survey study, the Japanese version of the Horne and Ostberg Morningness-Eveningness Questionnaire and Life Habits Inventory (LHI) were administered to approximately 1,500 university students. The survey results showed that the two types were significantly different from each other in terms of retiring and arising time, sleep latency, mood on arising, nap, adequate amount of sleep, number of times of staying awake all night, and variability in bedtime, arising time, and sleep length. These results suggested that evening type Ss had more irregular and/or flexible sleep-wake habits than morning type Ss. In the experimental study, 10 morning and 11 evening type Ss were selected from the population included in the survey study, and polysomnograms were obtained. The results showed that only in rapid eye movement (REM) latency did morning type Ss significantly differ from evening type Ss. REM latency might be related to personality factors, particularly to neuroticism and anxiety.

The present study investigated some differences between ‘morning’ and ‘evening’ types in life habits, particularly concerning meals, ingestion of caffeine and alcohol, and smoking. The Life Habits Inventory and the Japanese version of Home and Östberg Morningness-Eveningness Questionnaire were administered to approximately 1500 students, and data on life habits of the morning types were compared with those of the evening types. Significant differences between these types were found in frequency of night meals, smoking, and ingestion of caffeine and alcohol. Although significant differences were not found for mealtimes, 34.8% of the evening types typically did not eat breakfast. These differences were discussed from viewpoint of chronopharmacology and personality.

Wisconsin Card Sorting Test (WCST) performance was assessed in 24 heavy smokers and 12 nonsmokers recruited from universities in the United States and Japan. Half of the smokers performed the WCST after abstaining from tobacco for 12 hr, whereas the remaining smokers smoked a cigarette of their preferred brand immediately before the test. Nonsmokers did not smoke. The WCST was administered by computer, first with standard instructions and then a second time with abbreviated instructions that specified the 3 sorting criteria. Results from the second run indicated that abstinent smokers made significantly more perseverative responses and errors than did nonsmokers or smoking smokers. Results expand on previous findings of effects of smoking deprivation on human cognitive performance.Given the tremendous amount of information disseminated to the public in recent years concerning the health hazards of tobacco smoking, the fact that many heavy smokers continue to smoke is surprising. The most widely accepted interpretation of the smoking habit is that smoking represents a dependence on the drug nicotine (U.S. Department of Health and Human Services [US-DHHS], 1988; West, 1992). Although substantial evidence supports the notion of nicotine as an addictive drug, nicotine dependence does not easily fit into the paradigms that explain other drug dependencies. For example, nicotine is unlike "classic" addictive drugs, such as opiates, cocaine, and the amphetamines, in that it is a relatively weak primary reinforcer in certain animal selfadministration studies (J.H. Robinson & Pritchard, 1992;Slifer & Balster, 1985). Furthermore, repeated administration of nicotine does not lead to