Background: Temstem is a smartphone app developed with and for clinical voice hearing individuals with the aim to reduce their voice hearing distress and improve social functioning. Methods: A randomized controlled trial with adult outpatients suffering from distressing and frequent auditory verbal hallucinations (AVH) was conducted. Participants were randomized to unguided ‘Temstem+AVH monitoring’ or unguided ‘AVH monitoring only’ (control condition). Assessments were performed at baseline, post-intervention (week 5–6), and follow-up (week 9–10). Primary outcomes were voice hearing distress and social functioning, as measured with Experience Sampling Method (ESM), consisting of multiple daily questionnaires during six days. In addition, voices and mood were self-monitored with help of a daily reflective questionnaire. Analyses were linear regression models (intention-to-treat). Results: 44 Participants were allocated to Temstem and 45 to the control condition. No significant differences between the groups were found on both primary outcomes. Conclusion: Our results do not support the effectiveness of stand-alone use of Temstem versus symptom monitoring on voice hearing distress or social functioning in voice hearing individuals. In order to potentially improve effectiveness of an mHealth tool in a population of people with frequent and distressing voices, we recommend to involve persons with lived experience in all stages of development and research; to thoroughly test the (technological) usability before performing an RCT; to test whether guidance of a therapist is needed to optimize effectiveness; and to provide prompts to remind the user to actually use the tool.

Introduction Auditory verbal hallucinations (AVH) are prevalent experiences that can induce distress and impede social functioning. While most voice hearers benefit from antipsychotic medication or cognitive-behavioural therapy, additional effective interventions are needed to reduce the burden of experiencing AVH. Temstem' is an easily accessible and useable smartphone application that was developed by designers in close cooperation with voice hearers and experts. By using language games, Temstem aims to reduce distress and improve social functioning. Methods This is a single-blind multicentre randomised controlled trial with two arms: Temstem+AVH monitoring' versus AVH monitoring' (total n=100). Participants are adult patients who suffer daily from AVH and will be recruited in outpatient units. Primary assessment in daily life is made by the Experience Sampling Method (ESM) and daily monitoring with the PsyMate app. During an ESM period of 6 days, participants assess their mental state (including AVH and context) several times a day by filling in short questionnaires. There are three 6-day ESM periods: at baseline (week 0-1), post-treatment (weeks 5-6) and follow-up (weeks 9-10). In addition, during the entire 10-week study period, all participants monitor their AVH two times a day with a short assessment via the PsyMate app. Participants in the Temstem+AVH monitoring condition are provided with the Temstem app from week 1 to 6. Other assessments made at baseline, post-treatment and follow-up are based on questionnaires and a clinical interview. Ethics and dissemination The results from this study will provide an evaluation of the effectiveness of Temstem, a non-invasive and easily accessible app for voice hearers, and insight into the determinants of optimal use. Results will be disseminated unreservedly, irrespective of the magnitude or direction of the effects. This study protocol was approved by the Medical Ethics Committee of the VU University Medical Centre (METC number: 2015.435/NL53684.029.15). Trial registration number ISRCTN75717636; Pre-results.