RESUMO
The aim of the current study was twofold: (1) to systematically examine differences in fear conditioning between anxiety patients and healthy controls using meta-analytic methods, and (2) to examine the extent to which study characteristics may account for the variability in findings across studies. Forty-four studies (published between 1920 and 2013) with data on 963 anxiety disordered patients and 1,222 control subjects were obtained through PubMed and PsycINFO, as well as from a previous meta-analysis on fear conditioning (Lissek et al.). Results demonstrated robustly increased fear responses to conditioned safety cues (CS-) in anxiety patients compared to controls during acquisition. This effect may represent an impaired ability to inhibit fear in the presence of safety cues (CS-) and/or may signify an increased tendency in anxiety disordered patients to generalize fear responses to safe stimuli resembling the conditioned danger cue (CS+). In contrast, during extinction, patients show stronger fear responses to the CS+ and a trend toward increased discrimination learning (differentiation between the CS+ and CS-) compared to controls, indicating delayed and/or reduced extinction of fear in anxiety patients. Finally, none of the included study characteristics, such as the type of fear measure (subjective vs. psychophysiological index of fear), could account significantly for the variance in effect sizes across studies. Further research is needed to investigate the predictive value of fear extinction on treatment outcome, as extinction processes are thought to underlie the beneficial effects of exposure treatment in anxiety disorders.
Assuntos
Transtornos de Ansiedade/fisiopatologia , Condicionamento Clássico/fisiologia , Extinção Psicológica/fisiologia , Medo/fisiologia , HumanosRESUMO
Background: The use of oral contraceptives (OCs) has been associated with increased incidences of anxiety and depression, for which adolescents seem to be particularly vulnerable. Rather than looking at singular outcomes, we examined whether OC use is associated with depressive and anxiety symptom trajectories from early adolescence into early adulthood. Materials and Methods: Data from 178 girls were drawn from the Research on Adolescent Development and Relationships (RADAR-Y) younger cohort study. We used assessments on 9 waves from age 13 until 24. Developmental trajectories of ratings on the Reynolds Adolescent Depression Scale (RADS-2) and the Screen for Child Anxiety Related Emotional Disorders (SCARED) were compared between never and ever users of OCs. Results: Never users showed increases in depressive and anxiety symptoms in late adolescence, whereas OC users showed a stable level of symptoms throughout adolescence. This effect remained after adjusting for baseline differences between groups in romantic relationships, sexual debut, educational level, smoking, drinking, and drug use. Age of OC use onset did not significantly predict symptom development. Conclusions: OC use in adolescence was related to an altered developmental trajectory of internalizing symptoms, in which OC users did not show an increase in depressive and anxiety symptoms in late adolescence, whereas never users did. The question remains whether this altered symptom trajectory can be considered a protective effect of OC use on psychopathology. Additional research is needed to improve our understanding of the long-term consequences of OC use on mental health.
RESUMO
In this study, we examined the usefulness of weighted multidimensional scaling (WMDS) to decompose electrocortical activity of multiple brain sources. This electrocortical activity was evoked by checkerboard stimuli of four different spatial frequencies (0.75, 1.5, 3.0, and 6.0 cpd), presented to 12 participants under passive viewing conditions. Visual evoked potentials (VEPs) were recorded with a high density montage of 60 electrodes. These data were analyzed by using WMDS, resulting in four different dimensions, each of which can be considered equivalent to a potential scalp distribution, i.e. dipole source. The first of these dipole sources, which were determined by brain electrical source analysis (BESA), was predominantly activated by higher spatial frequencies, the second and third were predominantly activated by lower spatial frequencies, while the third and fourth sources were characterized by hemispheric asymmetry. Moreover, the neural activity of these brain sources was characterized by different patterns as a function of spatial frequency and time. The results suggest that visual processing of spatial frequencies comprises relatively separate subsystems with different spatiotemporal response characteristics.