Annual scores for five years were derived for environmental stress and psoriasis severity in 252 adults who had been hospitalized for psoriasis. Psoriasis severity varied with stress to a moderate but significant degree. Personality inventories failed to demonstrate any specific traits that would characterize the psoriatic patient, or a psoriatic whose disease specifically worsened following stress.
Baughman R, Sobel R. Psoriasis, Stress, and Strain. Arch Dermatol. 1971;103(6):599-605. doi:10.1001/archderm.1971.04000180025003