Psychological aspects of psoriasis
Psoriasis is a skin condition characterised by raised, red, scaling patches that cover the body to varying degrees, with a prevalence of 1-3% in Caucasian populations. There is evidence that sufferers hospitalised for treatment of then psoriasis are more depressed and more anxious than controls (e.g. Fava et al, 1980; Lyketsos et al, 1985), but conflicting evidence about whether psoriasis outpatients are also more depressed and anxious. The research presented in this thesis examined depression and anxiety in a group of psoriasis outpatients and found statistically significantly higher depression and anxiety levels than in a group of matched controls. The relationship over tune between area of coverage of psoriasis, depression and anxiety was examined in another group of psoriasis outpatients. Using multiple regression analysis, change in area of coverage between two assessments was a significant predictor of depression and anxiety at the second assessment, once levels at the first assessment had been accounted for. Self- esteem was also examined in this way and was found to be significantly related to psoriasis area of coverage, where worsening psoriasis was associated with a lowering of self-esteem. There were statistically significant differences between males and females. Pain had not previously been examined systematically in psoriasis outpatients, but was higher than pain in matched controls in the first study reported in this thesis. Consequently the quality of pain was examined further, and found not only to be significantly related to psoriasis area of coverage, but also was described in terms which suggested a distinct character to psoriasis pain. Fluctuations in sleep quality were also found to be significantly associated with psoriasis area of coverage. Visual assessment of psoriasis area of coverage was shown to be unreliable, so a computer program (SKINMAP) was developed to allow psoriasis lesions to be mapped onto a computer which then calculates area of coverage. SKINMAP estimates were shown to be statistically significantly more accurate and reliable than visual estimates. Informal conversations with psoriasis sufferers suggested that they held firm views about their condition which often did not coincide with medical views. Lay beliefs about psoriasis in a group of sufferers were therefore investigated in detail. Sufferers showed quite high levels of knowledge about the condition, but the nature of some common misconceptions was investigated through the use of semi-structured interviews, and the results highlighted the need for better patient education.