Low hair cortisol concentrations in obsessive compulsive disorder: A cross-sectional study.

Recent findings have highlighted the association between changes in the activity of the HPA axis, primarily its end-hormone, cortisol and OCD. However, to date, cortisol levels of OCD patients have been assessed mainly in body fluids, such as serum, saliva or urine, frequently leading to ambiguous results because of their inherent lack of stability. The aim of this study was to investigate time-integrated levels of stress exposure in 32 OCD patients and 32 sex and age-matched healthy controls by measuring endogenous cortisol in hair segments reflecting the last 3 months preceding hair collection. Psychometric parameters, including BDI, FQ, STAI, PSS and ECQ-R, were obtained in all participants; Y-BOCS was performed in the OCD patients. The OCD patients exhibited significantly higher scores in all psychometric instruments administered and lower hair cortisol concentrations than the healthy controls (p = 0.001, r = 0.41). No significant correlations were found between the HCC and the Y-BOCS total scores. After having sorted OCD patients into subtypes, according to the nature of their symptomatology, the "washers/cleaners" category showed the lowest HCC (compared to the "checking/harming", "ordering/symmetry" and "sexual/religious obsessions" categories). The novel finding of chronic low cortisol secretion in OCD patients could be attributed to a possible down-regulation of the HPA axis, as an adaptive response to chronic stress exposure. Given that the OCD subtypes reflect the great heterogeneity in the OCD spectrum, studies with larger samples should extend the investigation of HCC in patients with distinctive symptomatology, so as to develop a basis for better neuroendocrine profiling and understanding of the pathophysiology of OCD. Further work is needed in exploring HPA axis' activity over the natural course and treatments of the disorder.