Attentional Bias and Psychophysiological Arousal in Seasonal and Nonseasonal Depression Symptoms

The present study investigated cognitive specificity in individuals with seasonal depression symptoms (SDS) by comparing their attentional bias and psychophysiological arousal to cognitive schema-relevant stimuli with those in individuals with nonseasonal depression symptoms (NSDS) and nonseasonal and nondepressed individuals (control). Attentional bias was measured with responses on a modified Stroop test and a recall task, while psychophysiological arousal was measured with facial EMG recordings and image valence ratings during an image-viewing task. The Stroop word categories reflected constructs that were related to seasons (summer/winter), light (light/dark), and mood (happy/sad). The recall task involved incidental recall of the Stroop words following the Stroop test. The image-viewing task consisted of viewing and rating winter and summer scenes for degree of appeal while facial EMG recordings of the corrugator supercilii and zygomaticus major muscle regions were taken. Findings revealed that individuals in all three group conditions were slower to colour-name summer words than winter words, slower to colour-name light words than dark words, recalled more dark words than light words, frowned more (corrugator supercilii) when viewing high luminance than low luminance images, smiled more ( zygomaticus major) when viewing high luminance than low luminance images, smiled more when viewing high luminance winter images than either medium or low luminance winter images, and rated winter images as more appealing than summer images. The two groups with elevated depression symptoms (seasonal and nonseasonal) smiled less than the control group when viewing low luminance images. The results do not show a convergence across the different experimental tasks, and do not support the notion that seasonal individuals with depressed symptoms would respond more negatively than nonseasonal individuals with depressed symptoms to winter or low luminance stimuli. Limitations of the study are discussed.;Keywords: seasonal depression, nonseasonal depression, attentional bias, psychophysiological arousal, EMG, Stroop test.