Adolescent depression and externalizing problems: testing two models of comorbidity in an inpatient sample

Differentiating between additive (quantitative) and interactive (qualitative) effects of comorbidity has important treatment implications. This study illustrates the heuristic superiority of a multifactorial approach over simple group comparisons in testing quantitative versus qualitative models of comorbidity. Analysis of variance was used to compare 266 adolescent inpatients identified as depressed, externalizing, both, or neither on self-report measures of personality, school problems, and substance abuse. The results support quantitative rather than qualitative models of comorbidity. Depressed status related most strongly to group differences in interpersonal and self-critical concerns. Externalizing status related most strongly to group differences in school problems and drug use. Main effects for the two statuses together explained especially elevated levels of reactance and alcohol abuse among the comorbid adolescents.     

An investigation of monitoring for sleep-related threat in primary insomnia

In Study 1, individuals with primary insomnia (n=32) and good sleepers (n=38), recruited from a university population, completed a semi-structured interview. The interview assessed monitoring for sleep-related threat, negative thoughts and safety behaviours, at night and during the day. Compared to good sleepers, individuals with insomnia reported more frequent monitoring at night and during the day, more negative thoughts associated with monitoring at night and during the day, and the use of more safety behaviours associated with monitoring at night. A path analysis showed that the total monitoring frequency was significantly positively related to the score for total negative thoughts, which in turn, was significantly positively related to the total number of safety behaviours used. Study 2 aimed to test the generalisability of these findings in a clinical sample of individuals with primary insomnia (n=23). The results indicated that the clinical sample also engaged in monitoring for sleep-related threat, experienced negative thoughts and used safety behaviours. Further, more severe insomnia was associated with more negative thoughts and the use of more safety behaviours associated with monitoring at night. Together, these results are consistent with the proposal that monitoring for sleep-related threat functions to maintain insomnia by triggering negative thoughts and the use of safety behaviours. Future research is required to verify the proposed causal status of monitoring, using prospective designs and experimental manipulations.     

Correcting distorted perception of sleep in insomnia: a novel behavioural experiment?

Patients with primary insomnia overestimate their sleep onset latency (SOL) and underestimate their total sleep time (TST). The present study aimed to test the utility of a novel behavioural experiment designed to correct distorted perception of sleep among patients diagnosed with primary insomnia. Individuals with primary insomnia were asked to wear an actigraph and keep a sleep diary for three nights. On the following day, half were shown the discrepancy between the data recorded on the actigraph and their sleep diary (Shown-Discrepancy Group), the other half were not shown the discrepancy (No-Demonstration Group). Participants were then asked to wear the actigraph and keep a sleep diary for three further nights. Following the behavioural experiment, the Shown-Discrepancy Group estimated their SOL more accurately and reported less anxiety and preoccupation about sleep compared to the No-Demonstration Group. The theoretical and clinical implications of these findings are discussed.     

Visual memory decay is deterministic

After observers see an object or pattern, their visual memory of what they have seen decays slowly over time. Nearly all current theories of vision assume that decay of short-term memory occurs because visual representations are progressively and randomly corrupted as time passes. We tested this assumption using psychophysical noise-masking methods, and we found that visual memory decays in a completely deterministic fashion. This surprising finding challenges current ideas about visual memory and sets a goal for future memory research: to characterize the deterministic "forgetting function" that describes how memories decay over time.     

Suggestibility, social support, and memory for a novel experience in young children

This study examined 5- and 6-year-olds' suggestibility and interviewer demeanor as joint predictors of their memory for a novel experience. Session 1 consisted of children taking part in a novel laboratory event. Session 2 took place after approximately a 1-week delay and consisted of children completing both a memory test concerning what happened during the prior event and the Video Suggestibility Scale for Children (VSSC). During the second session, the interviewer behaved either supportively or nonsupportively. Greater acquiescence on the VSSC was associated with fewer correct responses to misleading questions about the laboratory event in the supportive and nonsupportive conditions and with more errors in response to specific questions in the nonsupportive condition. Results indicate that individual differences in children's suggestibility are related to the accuracy of their memory for separate events, although some of these relations may vary depending on the context in which children are interviewed.     

Individual differences in emotional memory: adult attachment and long-term memory for child sexual abuse

In the present study, attachment-related differences in long-term memory for a highly emotional life event, child sexual abuse (CSA), were investigated. Participants were 102 documented CSA victims whose cases were referred for prosecution approximately 14 years earlier. Consistent with the proposal that avoidant individuals defensively regulate the processing of potentially distressing information (Bowlby, 1980), attachment avoidance was negatively associated with memory for particularly severe CSA incidents. This finding was not mediated by the extent to which participants reported talking about the abuse after it occurred, although post abuse discussion did enhance long-term memory. In addition, accuracy was positively associated with maternal support following the abuse and extent of CSA-related legal involvement. Attachment anxiety was unrelated to memory accuracy, regardless of abuse severity. Implications of the findings for theories of avoidant defensive strategies and emotional memory are discussed.     

Attempts to control unwanted thoughts in the night: development of the thought control questionnaire-insomnia revised (TCQI-R)

The attempted control of intrusive, uncontrollable thoughts has been implicated in the maintenance of a range of psychological disorders. The current paper describes the refinement of the Thought Control Questionnaire Insomnia (TCQI; Behav. Cogn. Psychoth. 29 (2001)) through its administration to a sample (n=385) including good sleepers and individuals with insomnia. Several items with poor psychometric properties were discarded, resulting in a 35-item revised TCQI. Factor analysis revealed six factors; aggressive suppression, cognitive distraction, reappraisal, social avoidance, behavioural distraction, and worry. The attempted management of unwanted thoughts was compared across individuals with insomnia and good sleepers, and the impact of these strategies on sleep quality, anxiety and depression was investigated. With the exception of cognitive distraction, individuals with insomnia, relative to good sleepers, more frequently used every thought control strategy. The strategies of aggressive suppression and worry, in particular, appeared to be unhelpful, with the use of these strategies predicting sleep impairment, anxiety and depression. The strategy of cognitive distraction appeared to be helpful, with the use of this strategy predicting better sleep quality.     

Misperception of sleep can adversely affect daytime functioning in insomnia

This experiment was designed to investigate the relationship between subjective perception of sleep and daytime processes in primary insomnia. Twenty-two individuals with primary insomnia received positive or negative feedback about their sleep, immediately on waking, on three consecutive mornings. The positive feedback was that last night's sleep was good quality. The negative feedback was that last night's sleep was poor quality. Objective sleep on each of the three nights was estimated by actigraphy and did not differ across the three nights or the two feedback conditions. Negative feedback (based on 32 nights of data) was associated with more negative thoughts, sleepiness, monitoring for sleep-related threat, and safety behaviours during the day, relative to positive feedback (based on 34 nights of data). These results indicate that the impaired daytime functioning reported by insomnia patients is maintained, at least in part, by subjective perception of sleep.     

Transport of tools to food sites in tufted capuchin monkeys (<Emphasis Type="Italic">Cebus apella</Emphasis>)

Tool use and transport represent cognitively important aspects of early hominid evolution, and nonhuman primates are often used as models to examine the cognitive, ecological, morphological and social correlates of these behaviors in order to gain insights into the behavior of our early human ancestors. In 2001, Jalles-Filho et al. found that free-ranging capuchin monkeys failed to transport tools (stones) to food sites (nuts), but transported the foods to the tool sites. This result cast doubt on the usefulness of Cebus to model early human tool-using behavior. In this study, we examined the performance of six captive tufted capuchin monkeys (Cebus apella) in a tool transport task. Subjects were provided with the opportunity to transport two different tools to fixed food reward sites when the food reward was visible from the tool site and when the food reward was not visible from the tool site. We found that the subjects quickly and readily transported probing tools to an apparatus baited with syrup, but rarely transported stones to a nut-cracking apparatus. We suggest that the performance of the capuchins here reflects an efficient foraging strategy, in terms of energy return, among wild Cebus monkeys.     

A prospective study of memory for child sexual abuse: new findings relevant to the repressed-memory controversy

Previous research indicates that many adults (nearly 40%) fail to report their own documented child sexual abuse (CSA) when asked about their childhood experiences. These controversial results could reflect lack of consciously accessible recollection, thus bolstering claims that traumatic memories may be repressed. In the present study, 175 individuals with documented CSA histories were interviewed regarding their childhood trauma. Unlike in previous studies, the majority of participants (81%) in our study reported the documented abuse. Older age when the abuse ended, maternal support following disclosure of the abuse, and more severe abuse were associated with an increased likelihood of disclosure. Ethnicity and dissociation also played a role. Failure to report CSA should not necessarily be interpreted as evidence that the abuse is inaccessible to memory, although inaccessibility or forgetting cannot be ruled out in a subset of cases.