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

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.