Olfactory function and an explanatory model of pica revealed through a case report

BACKGROUND: Literature on pica is scarce, and despite multiple etiological explanations, there is no complete explanation of this condition due to its highly complex nature. One of the most prominent theories for explaining pica involves iron deficiency anemia. However, it is not clear how this condition induces pica; additionally, why patients choose to consume restricted substances and why these patients maintain these noxious behaviors are not understood. Interestingly, some patients with iron deficiency anemia present with olfactory cravings, and increasing evidence suggests that these patients have altered olfactory function, specifically increased susceptibility to and rates of nasal iron absorption. Nevertheless, these symptoms have not been systematically investigated in patients with pica. CASE PRESENTATION: We present a clinical case of a 56-year-old woman who had not undergone previous psychiatric evaluations; this patient presented with pica (characterized by the consumption of bricks) as well as iron deficiency anemia and was resistant to oral iron supplementation. Following a period of abnormal eating behaviors and menstrual dysregulation, the patient started sensing a highly pleasant smell emanating from bricks. Despite initially trying to resist this smell, she explained that it led her to crave and eat the bricks. She used to grind the bricks into powder to ingest them and refrained from adding water to enhance their flavor. Despite recognizing the noxious effects on her health, she described a pleasant feeling she had never experienced before and reported symptoms of anxiety and autonomic activation when she tried to stop eating the bricks. CONCLUSIONS: To the best of our knowledge, this is the first case in which an olfactory craving induced pica development. We propose a neurochemical explanation, which is based on altered olfactory function, for the onset of pica, choice of bricks as the craved substance, and perpetuation of the hazardous behaviors. This case introduces an important approach to pica, which has been severely lacking in the literature and has potential etiological implications.