Objectives: Reduction in the amount of information (storage capacity) retained in working memory (WM) has been associated with sleep loss. The present study examined whether reduced WM capacity is also related to poor everyday sleep quality and, more importantly, whether the effects of sleep quality could be dissociated from the effects of depressed mood and age on WM. Methods: In two studies, WM was assessed using a short-term recall task, producing behavioral measures for both the amount of retained WM information (capacity) and how precise the retained WM representations were (precision). Self-report measures of sleep quality and depressed mood were obtained using questionnaires. Results: In a sample of college students, Study 1 found that poor sleep quality and depressed mood could independently predict reduced WM capacity, but not WM precision. Study 2 generalized these sleep- and mood-related WM capacity effects to a community sample (aged 21–77 years) and further showed that age was associated with reduced WM precision. Conclusions: Together, these findings demonstrate dissociable effects of three health-related factors (sleep, mood, and age) on WM representations and highlighte the importance of assessing different aspects of WM representations (e.g., capacity and precision) in future neuropsychological research.

Comparative optimism can be defined as a self-serving, asymmetric judgment of the future. It is often thought to be beneficial and socially accepted, whereas comparative pessimism is correlated with depression and socially rejected. Our goal was to examine the social acceptance of comparative optimism and the social rejection of comparative pessimism in two dimensions of social judgment, social desirability and social utility, considering the attributions of dysphoria and risk-taking potential (studies 2 and 3) on outlooks on the future. In three experiments, the participants assessed either one (study 1) or several (studies 2 and 3) fictional targets in two dimensions, social utility and social desirability. Targets exhibiting comparatively optimistic or pessimistic outlooks on the future were presented as non-depressed, depressed, or neither (control condition) (study 1); non-depressed or depressed (study 2); and non-depressed or in control condition (study 3). Two significant results were obtained: (1) social rejection of comparative pessimism in the social desirability dimension, which can be explained by its depressive feature; and (2) comparative optimism was socially accepted on the social utility dimension, which can be explained by the perception that comparatively optimistic individuals are potential risk-takers.

Background: Few studies have specifically examined purpose in life among very old people, and we know of none that has used a prospective approach. The aim of this study was to examine changes in purpose in life over five years in very old men and women and to investigate whether depressed mood, malnutrition, inactivity in daily life, or cognitive impairment increased the risk for developing low purpose in life.

Methods: The study includes data from 51 participants (42 women and 9 men) living in northern Sweden who completed the Purpose in Life (PIL) Test once at baseline and again five years later.

Results: Purpose in life decreased over five years and the decrease was significantly associated with being a woman (p < 0.001) and having depressed mood (p = 0.009) or depression (p = 0.002) at baseline. There were no differences in baseline PIL scores between depressed and not depressed, but those who had depression had significantly decreased PIL scores after five years (p = 0.001).

Conclusion: A strong purpose in life does not seem to prevent very old people from developing depression, and being depressed at baseline and living with depression over five years is associated with a loss of purpose in life.

Low dietary intakes of the n-3 long-chain PUFA (LCPUFA) EPA and DHA are thought to be associated with increased risk for a variety of adverse outcomes, including some psychiatric disorders. Evidence from observational and intervention studies for a role of n-3 LCPUFA in depression is mixed, with some support for a benefit of EPA and/or DHA in major depressive illness. The present study was a double-blind randomised controlled trial that evaluated the effects of EPA+DHA supplementation (1·5 g/d) on mood and cognitive function in mild to moderately depressed individuals. Of 218 participants who entered the trial, 190 completed the planned 12 weeks intervention. Compliance, confirmed by plasma fatty acid concentrations, was good, but there was no evidence of a difference between supplemented and placebo groups in the primary outcome – namely, the depression subscale of the Depression Anxiety and Stress Scales at 12 weeks. Mean depression score was 8·4 for the EPA+DHA group and 9·6 for the placebo group, with an adjusted difference of − 1·0 (95 % CI − 2·8, 0·8; P = 0·27). Other measures of mood, mental health and cognitive function, including Beck Depression Inventory score and attentional bias toward threat words, were similarly little affected by the intervention. In conclusion, substantially increasing EPA+DHA intake for 3 months was found not to have beneficial or harmful effects on mood in mild to moderate depression. Adding the present result to a meta-analysis of previous relevant randomised controlled trial results confirmed an overall negligible benefit of n-3 LCPUFA supplementation for depressed mood.

Evaluating the ecological validity of neuropsychological tests has become an increasingly important topic. Previous research suggests that neuropsychological tests have a moderate level of ecological validity when predicting everyday functioning. The presence of depressive symptoms, however, may impact the relationship between neuropsychological tests and real world performance. The current study empirically tests this hypothesis in a sample of 216 participants with moderate to severe traumatic brain injury (TBI) who completed neuropsychological testing, self-report of mood symptoms, and report of everyday functioning six months post-injury. Contrary to some previous research and clinical lore, results indicated that depression was weakly related to neuropsychological test performance, although it was more strongly related to everyday functioning. Neuropsychological test performance was also significantly related to everyday functioning. The ecological validity of the neuropsychological tests together was not impacted by depressive symptoms, when predicting significant other ratings of functional status. However, patient self-report seems somewhat less related to neuropsychological performance in those with significant depressive symptoms. Neuropsychological test performance was equally related to self and other report of everyday functioning in patients without significant depressive symptoms. (JINS, 2007, 13, 377–385.)