Changes in Behaviour and Body Weight Following a Single or Double Social Defeat in Rats

In a series of experiments, the consequences of a single and double social conflict on various behaviours and body weight in rats were studied. Animals were subjected to social defeat by placing them into the territory of an aggressive male conspecific for one hour, either once, or twice at the same time on two consecutive days. To assess the consequences of social defeat, three experiments were performed with independent groups of rats. In the first experiment, an open field test was performed two days after the last conflict. Locomotor activity was strongly reduced after social defeat. There were no differences between the single and double defeat group. To assess the effects of social defeat on subsequent social behaviour, a second experiment was performed in which experimental animals were confronted with an unfamiliar non-aggressive rat two days after a single or double conflict. Social defeat resulted in a reduction of social contact with the unfamiliar conspecific. There was no difference between the single and double conflict group. In the third experiment, the effects of social conflict on food intake, body weight and saccharine preference were measured. Food intake was not affected after a single conflict, but in the double conflict group food intake was decreased for several days. Body weight gain was decreased after both single and double social defeat. The decrease was stronger in the double conflict group. Water intake and saccharine preference were not significantly affected. This study revealed that social defeat in rats causes pronounced changes in various behaviours and body weight. Different aspects of behaviour are differentially affected by defeat with respect to the magnitude and time course of the changes induced. Moreover, different behavioural parameters are differentially sensitive to repetition of the stressor.     

Effects of percentage occurrence of response members and its method of presentation on verbal discrimination learning and transfer

Each of 144 Ss learned two verbal discrimination (VD) lists for six trials. Two levels of percentage occurrence of response members (100% or 50%) were combined factorially with two methods of presentation and three transfer paradigms (C₁-I₂, C₂-I₁, C₂-I₂). In first-list learning, with one method of presentation in the 50,% ORM entire list was presented with only half the correct (C) items designated on each study trial, while in the second method only half the list was presented with all C items underlined. There were no differences between the two methods in the 100% ORM condition. The results indicated that % ORM was a significant variable in first-list learning, supporting the findings of Newby and Young (1972). No effect was found for method of presentation. Also, no real significant effect of these two variables was found in VD transfer. All results were interpreted in terms of the frequency theory of VD learning.     

Assessing the Need for Alcohol Abuse Programs for African-American College Students

The authors compare Black and White college student alcohol and other drug use. Significant differences were noted showing alcohol abuse to be less of a problem for Black students.     

Location and attention

A discrepancy exists in the literature concerning attention and visual localization accuracy. Prinzmetal, Amiri, Allen, and Edwards (1998), and Tsal and Bareket (1999a) found that localization accuracy increases with attention. Using an inattention paradigm, Rock, Linnett, Grant, and Mack (1992) found no difference between localization accuracy in three attention conditions: inattention, divided attention, and control. Using a similar inattention paradigm, the current study addressed this discrepancy. Subjects were instructed to perform a line judgement task, and attention for an additional location task was manipulated. In Experiment 1, location accuracy was worse in the inattention condition than in either the dividedattention or the control condition. There was no difference between the divided-attention and control conditions. Experiment 2 controlled for the possibility that improved location accuracy in the divided and control conditions was due to the expectation of performing a location response, rather than the manipulation of attention. Our results are in agreement with previous findings (Prinzmetal et al., 1998; Tsal & Bareket, 1999a) and suggest that the apparent discrepancy is due to coarse coding of the location responses in the study by Rock et al. (1992).     

Internet-delivered cognitive behavioral therapy for panic disorder with or without agoraphobia: a systematic review and meta-analysis

ABSTRACT

The current systematic review and meta-analysis examined the efficacy and effectiveness of internet-delivered cognitive behavioral therapy (iCBT) on panic disorder and agoraphobia symptom severity. Twenty-seven studies were identified. Results from nine randomised controlled trials (RCTs) showed that iCBT outperformed waiting list and information controls for panic (g = 1.22) and agoraphobia (g = .91) symptoms, but the quality of RCTs varied and heterogeneity was high. Results from three RCTs suggested iCBT may have similar outcomes to face-to-face CBT in reducing panic and agoraphobia symptoms. Within-group effect sizes between baseline and post-treatment were large for panic (n = 29, g = 1.16) and medium for agoraphobia symptom severity (n = 18, g = .73). Subgroup analyses of within-group pre/post treatment effect sizes showed larger within-group effect sizes for efficacy studies (n = 15) compared to effectiveness studies (n = 14) for panic severity (g = 1.38 vs. g = .98) but not agoraphobia severity. There was no impact of program length, inclusion or arousal reduction techniques, or degree of clinician support. Within-group effects of iCBT suggest the reduction in panic and agoraphobia symptom severity is maintained at 3–6 month follow-up (n = 12).