Psychopathological characteristics in patients with arginine vasopressin deficiency (central diabetes insipidus) and primary polydipsia compared to healthy controls

Abstract Objective Distinguishing arginine vasopressin deficiency (AVP-D; central diabetes insipidus) from primary polydipsia (PP), commonly referred to as psychogenic polydipsia, is challenging. Psychopathologic findings, commonly used for PP diagnosis in clinical practice, are rarely evaluated in AVP-D patients, and no comparative data between the two conditions currently exist. Design Data from two studies involving 82 participants 39 AVP-D, 28 PP, and 15 healthy controls (HC). Methods Psychological evaluations were conducted using standardized questionnaires measuring anxiety State-Trait Anxiety Inventory (STAI), alexithymia Toronto Alexithymia Scale (TAS-20), depressive symptoms (Beck's Depression Inventory-II (BDI-II), and overall mental health Short Form-36 Health Survey (SF-36). Higher STAI, TAS-20, and BDI-II scores suggest elevated anxiety, alexithymia, and depression, while higher SF-36 scores signify better overall mental health. Results Compared to HC, patients with AVP-D and PP showed higher levels of anxiety (HC 28 points 24–31 vs AVP-D 36 points 31–45; vs PP 38 points 33–46, P .01), alexithymia (HC 30 points 29–37 vs AVP-D 43 points 35–54; vs PP 46 points 37–55, P .01), and depression (HC 1 point 0–2 vs AVP-D 7 points 4–14; vs PP 7 points 3–13, P .01). Levels of anxiety, alexithymia, and depression showed no difference between both patient groups (P = .58, P = .90, P = .50, respectively). Compared to HC, patients with AVP-D and PP reported similarly reduced self-reported overall mental health scores (HC 84 68–88 vs AVP-D 60 52–80, P = .05; vs PP 60 47–74, P .01). Conclusion This study reveals heightened anxiety, alexithymia, depression, and diminished overall mental health in patients with AVP-D and PP. The results emphasize the need for careful interpretation of psychopathological characteristics to differentiate between AVP-D and PP.