Endocrine Abstracts

Background

Vasopressin, the main hormone regulating sodium-water balance, is involved in higher brain functions, e.g., cognition, emotion regulation and social functioning. In patients with an acute psychotic episode, increased vasopressin levels have been described and impaired higher brain functions are associated. Copeptin, the stable surrogate marker of vasopressin, has been shown to predict outcome in somatic diseases, i.e., stroke, myocardial infarction, and increases under psychological stress. In acute psychosis no reliable biomarker has proven to predict clinical outcome. The aim of this study was to investigate whether copeptin can be used as predictor of psychotic relapse in patients with an acute psychotic episode.

Methods

In this prospective, observational study we enrolled patients with an acute psychotic episode either within a schizophrenia spectrum disorder (SSD) or affective disorder. On hospital admission, baseline characteristics including current and prior medication, drug use and disease severity, i.e., Positive and Negative Syndrome Scale, Global Assessment of Functioning, Perceived Stress Scale, State-Trait Anxiety Inventory and Beck Depression Inventory, were assessed and fasting serum copeptin and cortisol were sampled. Psychotic relapse, defined as rehospitalization due to disease progression or reporting of psychotic relapse, was assessed one year after inclusion. The primary endpoint was copeptin at inclusion predicting time to psychotic relapse using Cox Proportional Hazard Model.

Results

We included 73 patients (74% male, mean [SD] age 35.3 [9.8] years) of whom 53 were diagnosed with SSD and 20 with affective disorder (n=17 bipolar, n=3 depression with psychotic symptoms). Serum copeptin predicted psychotic relapse with a hazard ratio (HR) of 1.1 (95%-CI 1.01-1.2, p=0.03) in patients with SSD, but not in affective disorder (HR 1.0, 95%-CI 0.8-1.1, p=0.6). Highest diagnostic accuracy for psychotic relapse was found at a copeptin cut-off of 7 pmol/l with a HR of 3.9 (95%-CI 1.3-11.8, p=0.01). Neither cortisol, prior or current antipsychotic medication, trigger of acute psychosis nor psychopathological ratings were significantly associated with psychotic relapse. Diagnosis of cannabis abuse was significantly associated with psychotic relapse in SDD (HR 3.3, 95%-CI 1.4, 8.0, p=0.008). Adjusting for cannabis abuse, copeptin remained significantly associated with psychotic relapse and identified patients with highest risk of psychotic relapse (p=0.015).

Discussion

Our study indicates that copeptin is a promising biomarker improving outcome prediction of psychotic relapse in patients with an acute psychotic episode within SDD. Our findings may be used to identify patients at risk of psychotic relapse and in need for a more intensive care.