Daily estimates of clinical severity of symptoms in bipolar disorder from smartphone-based self-assessments

Jonas Busk,Jakob E Bardram,Ole Winther,Maria Faurholt-Jepsen,Mads Frost,Lars Vedel Kessing

doi:10.1038/s41398-020-00867-6

Abstract

Currently, the golden standard for assessing the severity of depressive and manic symptoms in patients with bipolar disorder (BD) is clinical evaluations using validated rating scales such as the Hamilton Depression Rating Scale 17-items (HDRS) and the Young Mania Rating Scale (YMRS). Frequent automatic estimation of symptom severity could potentially help support monitoring of illness activity and allow for early treatment intervention between outpatient visits. The present study aimed (1) to assess the feasibility of producing daily estimates of clinical rating scores based on smartphone-based self-assessments of symptoms collected from a group of patients with BD; (2) to demonstrate how these estimates can be utilized to compute individual daily risk of relapse scores. Based on a total of 280 clinical ratings collected from 84 patients with BD along with daily smartphone-based self-assessments, we applied a hierarchical Bayesian modelling approach capable of providing individual estimates while learning characteristics of the patient population. The proposed method was compared to common baseline methods. The model concerning depression severity achieved a mean predicted R2 of 0.57 (SD = 0.10) and RMSE of 3.85 (SD = 0.47) on the HDRS, while the model concerning mania severity achieved a mean predicted R2 of 0.16 (SD = 0.25) and RMSE of 3.68 (SD = 0.54) on the YMRS. In both cases, smartphone-based self-reported mood was the most important predictor variable. The present study shows that daily smartphone-based self-assessments can be utilized to automatically estimate clinical ratings of severity of depression and mania in patients with BD and assist in identifying individuals with high risk of relapse.

Highlights

Bipolar disorder (BD) is a common and complex illness with an estimated prevalence of 1–2% and is regarded as one of the most important causes of disability worldwide[1,2]
Most patients presented with rather low severity of depressive and manic symptoms resulting in low Hamilton Depression Rating Scale (HDRS) and Young Mania Rating Scale (YMRS) scores
In the present study, clinical ratings of the severity of depression and mania were estimated from smartphonebased self-assessments collected from patients with BD

Summary

Introduction

Bipolar disorder (BD) is a common and complex illness with an estimated prevalence of 1–2% and is regarded as one of the most important causes of disability worldwide[1,2]. BD is associated with an elevated risk of mortality due to suicide and Currently, due to the lack of objective tests, the diagnostic process and the clinical assessment of the severity of depressive and manic symptoms relies on subjective information, clinical evaluation and rating scales[14]. Periodic clinical evaluations using clinical rating scales such as the Hamilton Depression Rating Scale (HDRS)[15] and the Young Mania Rating Scale (YMRS)[16] are currently used as the golden standard for assessing the severity of depressive and manic symptoms in patients with BD. Busk et al Translational Psychiatry (2020)10:194 scale consists of a series of items reflecting various symptoms of depression and mania, and these items are added up to produce a total score summarizing the current severity of depressive (HDRS) or manic (YMRS) state of the patient. The clinical evaluations are time consuming and require a specialist who is trained and experienced in using the rating scales to produce consistent, valid and reliable results

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