2026 Volume 2 Issue 1 Pages 68-80
Background: Iron deficiency is common in children and in women of reproductive age. In psychi atric practice, insomnia, fatigue, anxiety, difficulty concentrating, and restlessness may become the presenting complaints. However, non-anemic iron deficiency, as well as coexistence of functional i ron deficiency with elevated ferritin due to inflammation and absolute iron deficiency, that is, mix ed iron deficiency, is easily overlooked.
Objective: To define the concept of iron deficiency in a broad sense, critically examine the relati onship between iron deficiency and the above symptoms regardless of the presence or absence of anemia, and clarify both the potential applicability and the limitations of this perspective in routin e psychiatric practice, especially in cases in which conventional psychiatric explanations alone do not fully account for the clinical picture.
Main Text: This review presents four clinical phenotypes of iron-restricted states: (1) non-anemic iron deficiency, (2) non-anemic iron utilization disorder, (3) iron deficiency anemia, and (4) anemi a of inflammation, and summarizes the broader concept of iron deficiency and its pathophysiology. Clinical assessment should be based not only on iron-related indices such as ferritin, transferrin s aturation (TSAT), total iron-binding capacity (TIBC), C-reactive protein (CRP), and mean corpuscu lar volume (MCV), but also on symptoms, physical findings such as nail changes and cold intoler ance, sex and age, dietary patterns, and intestinal condition. These findings are important for decid ing whether iron preparations should be used and for providing lifestyle guidance aimed at improv ing iron metabolism. Because ferritin may increase in subtle inflammation that does not raise CR P, TSAT, TIBC, and copper/zinc (Cu/Zn) values, which may reflect subtle inflammation, may also serve as useful references in clinical practice. Observational studies, particularly in young menstru ating women and perinatal women, have suggested associations between iron deficiency and depres sive symptoms, fatigue, anger or irritability, and reduced quality of life. In intervention studies an d meta-analyses, populations with iron deficiency without anemia have shown relatively consistent improvement in fatigue, physical well-being, and some anxiety and cognitive indicators, whereas di rect improvement in depressive symptoms remains limited.
Conclusion: In psychiatric practice, there is value in systematically considering iron deficiency in patients with difficult-to-explain insomnia, fatigue, or restlessness. This approach may broaden diffe rential diagnosis and support more appropriate individualized clinical decisions. In mixed iron defic iency, causes of inflammation should first be explored and addressed as far as possible before abs olute iron deficiency is treated, and indiscriminate administration of iron preparations should be av oided.
