Converging Neurobiological Evidence In Primary Polydipsia Resembling Obsessive-Compulsive Disorder.

Compulsive water drinking can have phenomenological and pharmacotherapeutic similarities with obsessive-compulsive disorder (OCD). Substantiating neurobiological evidence is lacking for such an association. We report a patient who was referred with a diagnosis of primary polydipsia with no signs of organic pathology in structural neuroimaging. However, positron emission tomography revealed basal ganglia hypometabolism indicating that primary polydipsia with compulsive water drinking is neurobiologically related to OCD. The diagnostic complexities displayed by primary polydipsia and the use of systematic evaluation with supporting neuroimaging evidence in reaching a reliable diagnosis are discussed. The neurobiological evidence will foster the treatment decisions for starting anti-OCD measures when clinicians encounter patients with primary polydipsia exhibiting compulsive patterns of drinking. Nevertheless, such findings need to be replicated in future studies with a larger sample size.