Carissa L. Broadbridge

Potency of naltrexone to reduce ethanol self-administration in rats is greater for subcutaneous versus intraperitoneal injection

The opioid antagonist naltrexone (NTX) is used to treat alcohol dependence and may reduce alcohol consumption by selectively blocking opioid receptors. In rat experiments, discrepancy exists across studies regarding the potency of NTX to reduce ethanol consumption. One cause of this discrepancy may be the use of different routes of NTX administration (e.g., intraperitoneal vs. subcutaneous). The purpose of this study was to directly compare the effects of intraperitoneal and subcutaneous injections of NTX on ethanol self-administration. Rats pressed a lever for a sweetened ethanol solution (10% wt/vol in 0.1% saccharin) during 20 min daily sessions. One group received intraperitoneal injections of 1, 3, 10, and 30 mg/kg NTX before the sessions. Another group received subcutaneous injections of 0.03, 0.1, 0.3, and 1 mg/kg NTX before the sessions. The group that received subcutaneous NTX was also tested with a single intraperitoneal injection of 0.3 mg/kg NTX. Naltrexone significantly reduced ethanol self-administration, and NTX was more potent when administered via subcutaneous injection versus intraperitoneal injection. Ethanol intake (g/kg) was significantly reduced after subcutaneous injection of NTX 0.1 mg/kg and higher. In contrast, ethanol intake was significantly reduced after intraperitoneal injection of NTX 3 mg/kg and higher. A comparison of the NTX ED(50) values showed that subcutaneous NTX was approximately 30-fold more potent than intraperitoneal NTX. For the subcutaneous 0.3 mg/kg NTX dose, a detailed bin analysis showed that responding during the first 2 min after injection was similar to that during the first 2 min after a saline injection while responding after NTX decreased in subsequent bins. These findings suggest that researchers should carefully consider the route of NTX administration when discussing potency and selectivity of NTXs effects on ethanol-related behaviors in rats. These findings further support the notion that NTX acts by terminating responding early rather than reducing the initial responding.

Latent constructs of the Autobiographical Memory Questionnaire: A recollection-belief model of autobiographical experience

Many researchers employ single-item scales of subjective experiences such as imagery and confidence to assess autobiographical memory. We tested the hypothesis that four latent constructs, recollection, belief, impact, and rehearsal, account for the variance in commonly used scales across four different types of autobiographical memory: earliest childhood memory, cue word memory of personal experience, highly vivid memory, and most stressful memory. Participants rated each memory on scales hypothesised to be indicators of one of four latent constructs. Multi-group confirmatory factor analyses and structural analyses confirmed the similarity of the latent constructs of recollection, belief, impact, and rehearsal, as well as the similarity of the structural relationships among those constructs across memory type. The observed pattern of mean differences between the varieties of autobiographical experiences was consistent with prior research and theory in the study of autobiographical memory.

The Influences of Event Centrality in Memory Models of PTSD

Summary The consequences of events for well-being are influenced by individual and situational factors that are often studied in isolation. In the research reported here, a large (N = 489) nonclinical sample of college students reported their most traumatic event, posttraumatic stress disorder (PTSD) symptoms, depressive symptoms, personality traits, and characteristics of their event memory. This study achieved three major goals. First, we identified the highest types of stress event types in this population as disruptions of interpersonal relationships, homicides/assaults on others, and assaults/accidents involving themselves. Second, we established that the effects of memory characteristics such as vividness, belief, and impact on PTSD symptoms are mediated by the centrality of the event to identity. Third, we affirmed the hypothesis that a structural model of the influence of personality factors on PTSD symptoms has a higher level of concurrent validity if event centrality is included as a mediator of those influences. Copyright

Longitudinal determinants of energy levels in knowledge workers

Objective:Increasingly, workers in the service, welfare, and health care sectors suffer adverse effects (ie, depression, burnout, etc) of “low-energy syndromes.” Less is known about energy-based outcomes among knowledge workers. This study aimed to identify determinants of self-rated energy in knowledge workers and examine how these determinants change over time. Methods:In collaboration with a large union and employer federation, 317 knowledge workers in Sweden responded to the health and productivity survey three times. Results:At each assessment, worry, satisfaction with eating habits, and work-effectiveness were predictive of energy levels; however, only work-effectiveness covaried with energy over time. Conclusions:This study suggests that perceived work-effectiveness is an important factor in preventing knowledge workers from experiencing “low-energy syndromes.” Lifestyle factors also play a role. Therefore, multifaceted interventions for increasing energy are needed.

Acculturation and post-migration psychological symptoms among iraqi refugees: A path analysis

Refugees frequently experience symptoms of posttraumatic stress and depression, which impede their acculturation in the new host country where they are resettling. There are few longitudinal studies investigating predictors of mental health and acculturation during the early postmigration period. We conducted a longitudinal study of 298 Iraqi refugees, assessing them upon arrival to the U.S. and 1 year after migration. Premigration trauma was associated with increased PTSD and depressive symptoms at baseline, and with decreased acculturation 1 year later. Resilience was associated with depressive symptoms at 1-year follow-up, but not with other resettlement outcomes (PTSD symptoms, English-language skills, or acculturation). PTSD and depressive symptoms at baseline predicted the same symptoms at 1-year follow-up, but not any other resettlement outcomes. The number of chronic diseases at baseline predicted worse PTSD and depressive symptoms, acculturation, and English language skills at 1-year follow up. Postmigratory exposure to daily stressors and less social support predicted worse 1-year outcomes. Results suggest that interventions that aim to improve mental health and promote acculturation among refugees should assess their history of trauma, chronic disorders, and psychological symptoms soon after migration, and promptly provide opportunities for social support.