We found a link between the degree of adaptation to prolonged semi‐fasting expressed by the blood levels of thyroid hormones (fT3) and the level of depression symptoms (BDI score), social anxiety symptoms (fear sub‐scale score in the LSAS score), and OCD symptoms (sub‐score doubt and awareness on the MOCI), taking the chronology of occurrence of the comorbidities studied into account (respectively MDE, GAD, social phobia, and OCD) and the other confounding variables identified (including, for almost all symptoms, duration of AN evolution and albumin for social phobia symptoms). This evidence concerns the gene ALB and major depressive disorder.