Hawks and Doves: Testing the Hypothesis from Darwinian Medicine on the Psoriasis Model

Darwinian medicine postulates a concept of "allostatic overload" as a trigger for certain types of diseases. It also postulates two behavioural strategies, doves and hawks, which differ in the immune system responses to allostatic load. The Darwinian medicine framework postulates that hawks should have greater incidence of autoimmune and inflammatory diseases. This hypothesis was tested on the psoriasis model, as there are two types of psoriasis: type I, with a genetic component, and type II, regarded as reactive, i.e. dependant upon exogenous factors. Since psoriasis type I is less dependant upon environmental triggers, we do not expect differences between the personality profiles of these patients and the comparable group of dermatological patients. However, we do expect a specific personality profile in patients with psoriasis type II, a disease which can be considered a consequence of allostatic overload. We compared MMPI-201 profiles of 44 patients with psoriasis type I, 26 patients with psoriasis type II, and 70 patients diagnosed with other skin diseases. Only patients diagnosed with psoriasis type II showed a clinically indicative Hs-D-Hy profile. Furthermore, although patients with a type II psoriasis had objectively poorer clinical condition (as measured with PASI index and exacerbation of illness), the perception of psoriasis-induced stress in everyday life was related only with the personality profile, and not with the type of psoriasis. Since behavioural traits of people with Hs-D-Hy profile resemble those of hawks, we consider this finding to be indirect evidence in favour of the proposed hypothesis.