1 The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR. Electronic address: wtchien@cuhk.edu.hk.
2 The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T, Hong Kong SAR.
3 College of Nursing and Midwifery, Charles Darwin University, Darwin, Northern Territory, Australia; Faculty of Nursing, Chiang Mai University, 239 Huay Kaew Road, Muang District, Chiang Mai Thailand, 50200. Electronic address: daniel.bressington@cdu.edu.au.
4 Psychological Health Center, Concordia University, Montreal, Quebec, Canada. Electronic address: cecilskchu@gmail.com.

This study aimed to test the effectiveness of an acceptance-based medication adherence intervention for people with early-stage psychosis. An assessor-blind, three-arm randomized controlled trial design was used. One hundred and twenty-six participants who were adults with =3 years of psychosis were recruited from four district Integrated Community Centers for Mental Wellness in Hong Kong. They were randomly assigned to receive a 10-session acceptance-based, insight-inducing medication adherence therapy (AIM-AT) intervention, a conventional psychoeducation group program, or usual treatment (n = 42 per group). Primary outcomes were medication adherence and insight into the illness/treatment. All study outcomes were measured at recruitment and immediately, 6 months, and 12 months post-intervention. Participants in the AIM-AT experienced statistically significant improvements in the primary outcomes (levels of medication adherence and insight into illness/treatment), when compared to those in the other two groups over the 12-month follow-ups. The AIM-AT group also had significantly greater improvements in psychotic symptoms, psychosocial functioning, service satisfaction, length of rehospitalization, and total number of patients hospitalized over the follow-up period. These findings support the effectiveness of the AIM-AT to improve medication adherence, psychosocial health, and service satisfaction in people with early-stage psychosis.