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.

Background: Temstem is a mobile application developed in cooperation with voice-hearing persons to help them cope with distressing voices. After psychoeducation about voice hearing, Temstem offers two functions: Silencing is a mode designed to inhibit voice activity through the processing of incompatible language; the Challenging mode introduces dual tasking (as used in eye movement desensitisation and reprocessing) designed to reduce the emotionality and vividness of a voice memory. Two different language games, Lingo Tapper and Word Link, are provided, containing both functions. This study aimed to explore the momentary effects of Temstem on voice-hearing distress, emotionality and vividness in a naturalistic sample of voice-hearing app users. Method: Temstem is freely available in the Netherlands. We collected data through the app from 1048 individual users who had given informed consent for the study. We assessed changes in pre- and post-session scores on distress, emotionality and vividness, and we evaluated differences in outcomes between the games and whether effects remained stable over multiple sessions. Results: Users had been hearing voices for an average of 4.95 years; 79 % had been informed about Temstem by a mental health therapist or coach. After a Silencing session, voice-hearing distress was reduced, t(958) = 27.12, p < .001, d = 0.49; the degree of reduction remained stable after repeated use, F(1, 7905.57) = 1.91, p = .167. After a Challenging session, emotionality, t(651) = 23.16, p < .001, d = 0.74, and the vividness of voice memories were reduced, t(651) = 22.20, p < .001, d = 0.71; both diminished slightly with frequent use, F(1, 2222.86) = 7.21, p < .05; F(1, 2289.92) = 4.25, p < .05. In comparison with Lingo Tapper, larger reductions were seen for a Word Link game: emotionality t(226) = 2.88, p < .005, d = 0.21; vividness t(226) = 2.29, p < .05, d = 0.17. Discussion: In this heterogeneous sample of voice-hearing individuals, Temstem appeared to be a promising coping tool; momentary voice-hearing distress and the emotionality and vividness of voice statements were reduced after a Temstem session. Despite important limitations and the need for more research, naturalistic studies of user app data may yield interesting and generalisable findings.