Diurnal mood variation in major depressive disorder

Depression disturbs mood, but a clear picture of diurnal mood rhythms in depression has yet to emerge. This study examined variations in positive affect (PA) and negative affect (NA), two dimensions of mood that generate diurnal patterns among healthy individuals. Repeated measurements of NA and PA in daily life were obtained over 6 days from 47 depressed outpatients and 39 healthy individuals using the Experience Sampling Method. Relative to healthy individuals, depressed individuals exhibited increasing PA levels during the day with a later acrophase. In contrast, depressed persons' NA exhibited a more pronounced diurnal rhythm and was more variable from moment to moment than healthy individuals'. Ambulatory mood measurements in depression suggest distinct diurnal disturbances of positive and negative affect.     

Effects of manipulating valence and arousal components of mood on specificity of autobiographical memory

An important cognitive deficit in clinical depression is the inability to be specific in recalling personal memories, a phenomenon coined "overgeneral memory" by Williams and Broadbent. Although there is general consensus that overgeneral memory is not state-dependent, most of the evidence originates from studies of this effect in clinical populations. The two components of mood, valence and arousal, were manipulated to examine their influence on memory specificity in a nonclinical sample of university undergraduate students. In Exp. 1, a Velten procedure was used to induce elated, depressed, or neutral mood states. No difference was found in autobiographical memory specificity among the three groups. In Exp. 2, high and low arousal states were induced through physical exercise. A low arousal state resulted in an increased proportion of overgeneral memories, suggesting that this memory phenomenon may be influenced by the arousal component of mood.     

Executive functioning in normal aging: a study of action planning using the Zoo Map Test

A particularly important aspect of executive functioning involves the ability to form and carry out complex plans, that is to say planning. This study aimed to investigate planning in 18 older and 16 younger normal participants using an ecological planning subtask derived from the Behavioural Assessment of the Dysexecutive Syndrome test battery, the "Zoo Map Test." There are two trials. The first trial consists of a "high demand" version of the subtask in which the participants must plan in advance the order in which they will visit designated locations in a zoo (formulation level). In the second, or "low demand" version, the participant is simply required to follow a concrete externally imposed strategy to reach the locations to visit (execution level). The two-way ANOVAs mainly showed more difficulties in elderly adults than in younger adults, more difficulties in formulation level than in execution level, and lastly a greater difference between formulation and execution in older participants than in younger adults. These results suggest that elderly participants have some problems developing logical strategies whereas they are able to execute complex predetermined plans.     

Suicide attempts and family history of suicide in three psychiatric populations

The influence of a family history of suicide on suicide attempt rate and characteristics in depression, schizophrenia, and opioid dependence was examined. One hundred sixty inpatients with unipolar depression, 160 inpatients with schizophrenia, and 160 opioid-dependent patients were interviewed. Overall, a family history of suicide was associated with a higher risk for suicide attempt, with high-lethality method, with repeated attempts, and with number of attempts, while the interaction between family history and diagnostic group was not significant. Thus, a positive family history of suicide was a risk factor for several suicide attempt characteristics independent of psychiatric diagnosis.     

Referential understanding of videos in chimpanzees (Pan troglodytes), orangutans (Pongo pygmaeus), and children (Homo sapiens)

Performance on identical search tasks based on cues directly perceived or indirectly perceived through video were compared among a group of 4 adult chimpanzees (Pan troglodytes), a group of 2 adult orangutans (Pongo pygmaeus), and a group of 36 children (between 2 and 3 years of age). Children comprehended directly perceived cues but had difficulty with video cues. In contrast, chimpanzees and 1 orangutan were successful in using video to guide their search for a hidden object. Two follow-up studies with 3-year-old children demonstrated the importance of more distinct perceptual and verbal cues in aiding children's understanding of video as referring to real-world events.     

Nonlinearity in the Epidemiology of Complex Health and Disease Processes

Theoretical Medicine and Bioethics - The challenges posed by chronic illness have pointed out to epidemiologists the multifactorial complex nature of disease causality. This notion has been...     

Lexicographic aggregation of semiorders

It is well known that the lexicographic aggregation of complete preorders gives a complete preorder. Unfortunately, this property is no longer true when the lexicographic rule is applied to semiorders. In this paper we study some ways of defining a lexicographic aggregation of semiorders and the properties of the resulting structures.     

Perceived self in infancy

Research is presented suggesting that an implicit sense of self is developing from birth, long before children begin to manifest explicit (conceptual) self-knowledge by the second year. Implicit self-knowledge in infancy is rooted in intermodal perception and action. Studies are reported showing that at least from 2 months of age, infants become increasingly systematic and deliberate in the exploration of their own body and the perceptual consequences of self-produced action. From such exploration, infants develop a sense of their own body as a differentiated entity, situated and agent in the environment. Based on recent empirical findings, the perceptual determinants of such implicit sense of self are discussed.