Psychological stress and psoriasis: experimental and prospective correlational studies.
Using a dismantled time-series design, 18 subjects with psoriasis symptoms on the scalp were randomly assigned to four groups and six dropped out: meditation (N = 5); meditation and imagery (N = 4); waiting list (N = 5); and no treatment control group (N = 4). Treatment lasted 12 weeks, with 4 weeks pre- and post-baseline periods. An assessment control group was also used during baseline periods (N = 4). The severity of psoriasis symptoms was reliably rated by dermatologists. A time-series multivariate regression analysis controlling for extraneous factors influencing psoriasis symptoms, revealed a significant difference between the mean psoriasis ratings of treatment and control groups after treatment (partial r = 0.30, p less than 0.01). No additional impact was associated with the use of the imagery technique (partial r = 0.06, p less than 0.05). Four subjects in the treatment groups, two in each condition, succeeded in clinically improving their psoriasis symptoms and none deteriorated. The practice of meditation may be clinically effective for some patients in reducing their psoriasis symptoms. For one of the control groups, the relation between psychological stress and psoriasis was examined prospectively over a period of 20 weeks using standardized measures. A time-series multivariate statistical method indicated an average positive correlation between the severity of psoriasis symptoms and psychological distress (partial r = 0.31, p less than 0.01) and the impact of adverse life events (partial r = 0.23, p less than 0.05); there were, however, important individual differences. Stress reduction techniques can thus be regarded as part of the treatment offered to some patients suffering from psoriasis.