OBJECTIVES Central Nervous System (CNS) studies often incorporate the use of patient-reported outcomes (PROs) because of the nature of disorders being studied and their dependence on the subjective reports of study subjects1. To date, limited data has been published that sheds light on the types of instruments that are collected electronically (ePRO) in CNS trials. This research studied the breadth and depth of ePRO use through the analysis of a data set containing details of ePRO use in phase I-IV CNS drug trials. METHODS A study of the characteristics of ePRO use in CNS clinical drug trials was undertaken to understand the breath of CNS disorders areas in which ePRO is being used as well as to understand how ePRO is being used within these trials. A dataset of 91 clinical trials was analyzed by using fields that describe each protocol's key elements including ePRO instrument, Phase, Assessment Frequency, Disorder and Target Population. RESULTS The analysis determined that Depression and sleep disorders respectively represented 33.3% and 34% of ePRO use for this dataset. Overall, ePRO was used in 12 different CNS disorders. ePRO was most often used to collect primary efficacy data (24%), but other uses included secondary efficacy (22%) and safety (4.4%) data. The most common reporting frequency was for screening or study eligibility assessment (24%); this was followed closely by daily (19.8%) assessment. Of interest was that 79% of the time, a named instrument is used as opposed to a diary or symptom questionnaire (21%). CONCLUSIONS This research shows that PROs are not only being collected electronically, but that ePRO use within CNS clinical trials is both broad and deep. Limitations of this study include the clinical trials of this dataset which can not be necessarily generalized as representative of all CNS ePRO use.