In recent years, a growing number of studies have demonstrated that individuals can exert higher motivation when working in a group compared to working individually. This is particularly true for less capable, inferior group members. To aggregate these findings and to examine preconditions as well as moderating influences on motivation gains of inferior group members, the authors conducted a meta-analysis (17 studies, N=2,240). Results indicated that the overall motivation gain effect of inferior group members observed is moderate and significant (g=.60). Moderator analyses revealed substantial influences of task structure, performance information, physical presence, gender, and task type.

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SUMMARYThe present study investigated dream recall frequency and dream content of patients with insomnia in comparison to healthy controls. Patients' dream recall frequency was elevated, due mainly to their heightened frequency of nocturnal awakenings. Dream content seems to reflect waking life stressors found in these patients, i.e. dream emotions were more negative and dreams were characterized by themes of depression, 'negatives' in self-description and health themes. Patients taking antidepressants showed lower dream recall frequency than patients without any medication; benzodiazepine intake, however, did not affect dream recall frequency. Both drug groups reported more positively toned dreams than drug-free patients. It is suggested that future studies should use more dreams per subject in order to reduce error variance of the dream content measures and more detailed measures of waking life stress. dream content, dream recall, insomnia, antidepressants, benzodiazepines INTRODUCTION al., 1996b) in the pre-sleep situation impair sleep and affect daytime mood adversely which, in turn, leads to increased Insomnia is a common complaint in our society. Hohagen et cognitive arousal and/or sleep-related anxiety (e.g. Dreßing al. (1993), for example, reported that 47% of the patients and Riemann, 1994). consulting general practices suffer from mild to severe insomnia.The present study focuses on dream life of patients with Aetiological models of insomnia (e.g. Dreßing and Riemann, insomnia for two reasons. First, their dreams could shed light 1994; Hauri, 1994; Perlis et al., 1997) stress the importance of on how these patients experience their situation subjectively, both trait vulnerabilities and precipitating factors responsible i.e. it was expected that daytime stressors as well as personality for initiating and maintaining insomnia. On one hand, trait patterns are reflected in their dreams. The general hypothesis factors differentiate between patients with insomnia and healthy stating that dreams reflect waking life is called the continuity controls such as a depressive personality pattern (e.g. Kales et hypothesis of dreaming (e.g. Cartwright and Lamberg, 1992;al., 1983; Hoffmann et al., 1996a), trait anxiety (e.g. Monroe, Domhoff, 1996). Secondly, the specific sleep pattern of patients 1967; Angst et al., 1989), inadequate stress-coping behaviour with insomnia allows testing of whether sleep parameters such (e.g. Heyden et al., 1984;Schindler et al., 1984 Schindler et al., , 1988 and as nocturnal awakenings are related to dream recall frequency. chronic somatic disorders (e.g. Kales et al., 1983; With regard to dream recall frequency in healthy controls, al., 1991). On the other hand, precipitating factors such as several investigations found a positive correlation between major life events and occupational stress were present at the dream recall frequency and the frequency of nocturnal onset of insomnia, as reported by most of the patients (e.g.awakenings (e.g. Cory et al., 1975; Halliday, 198...

25-Hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, calcium, phosphate and parathyreoidal hormone levels were assessed in 34 patients with schizophrenia (DSM-III-R, 44% female, mean age 38.9 +/- 2.1 years), 30 patients with alcohol addiction (16% female, mean age 48.7 +/- 2.2 years), 25 patients with major depression (56% female, mean age 57.6+/- years) and 31 healthy controls. Only 25-hydroxyvitamin D3 and 1,25-dihydroxvitamin D3 levels were significantly lower in all groups of psychiatric patients than in normal controls, but not phosphate, calcium and parathyreoidal hormone levels. Significant differences in the vitamin D levels could not be found between the three psychiatric groups. These findings do not support the idea that vitamin D is specifically involved in the pathophysiology of depression. The difference in patients as compared to the healthy controls might be related to a different social background resulting in differing habits e.g. of nutrition.

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