[From pseudopregnancy to anorexia nervosa].

Translated in the primeval environment where humanization evolved during millions of years (man's environment of evolutionary adaptation, according to Bowlby), the characteristic behaviours of anorectics and bulimics do not look unfavourable but on the contrary adaptive, helping to the survival of the group or kinship (hyperactivity, altruistic feeding, etc.). Analogies, indeed homologies, exist in many animal species, distant or closely related to us (social insects, birds, mammals including primates) observed in nature. It concerns altruistic behaviours described among individuals, for the most part females, referred to as allomothers (aunts) or helpers (co-operative breeding) in ethological terms. From this evolutionary perspective, a biological genetic basis would exist in anorexia and bulimia, as a component of a phylogenetic inheritance of the K-selection strategy of reproduction. At the present time, anorexia would be a pathological extreme of this strategy, whereas pseudocyesis would be, on the contrary, one of the r-selection. Diverse and varying sociocultural and demographic conditions prevailing in modern world would revive either of these phylogenetic programs of reproductive strategies, leading as the case may be, to adaptive or pathological reproductive or helping behaviours.