Mental health problems are important causes of disability and economic costs worldwide. Randomised clinical trials examining the treatment of mental health disorders measure heterogeneous outcomes, causing difficulties in data synthesis, interpretation and translation into clinical practice. The aim of the Patient Important Outcomes in Psychiatry (PIO-Psych) Initiative is to develop an overarching, transdiagnostic research-based and consensus-based core outcome set for adult mental health disorders.

The development of the PIO-Psych transdiagnostic core outcome set will include three phases: (1) a systematic scoping review of the literature to develop the initial list of outcomes for the Delphi study; (2) a Delphi study in three rounds including people with lived experience of mental health disorders and their relatives, clinicians, researchers and others (administrators, mental healthcare policymakers, philosophers); (3) a hybrid consensus meeting to agree on the final overarching, transdiagnostic core outcome set and corresponding time points of assessment of each outcome.

Ethical approval is not applicable to this study according to the Research Ethics Committee of the Capital Region of Denmark, as it is not an interventional study. All data will be reported anonymously, and it will not be possible to identify study participants. Results will be disseminated via stakeholder and research networks and peer-reviewed publications.

The PIO-Psych Initiative was pre-registered with COMET (Core Outcome Measures for Effectiveness Trials) on 17 May 2024 (https://www.comet-initiative.org/Studies/Details/3125).

This study aimed to understand antiretroviral therapy (ART) adherence norms and beliefs among men living with HIV (MLHIV) in Mozambique, gauge the impact of misconceptions and harmful beliefs, evaluate perceived HIV service quality and assess the effectiveness of a behaviour change campaign (Somos Iguais), particularly among men aged 25–34 years.

A mixed-methods, cross-sectional study using quantitative and qualitative approaches.

In Mozambique, over two million individuals live with HIV. This study was conducted in Maputo, Nampula and Sofala provinces.

The study comprised 10 focus group discussions with MLHIV aged 18–35 years and 58 indepth interviews with MLHIV aged 15–35 years across diverse subpopulations. A quantitative cross-sectional survey was completed by 1934 MLHIV aged 25–34 years.

Population Services International developed a behaviour change campaign in 2020 aimed at reaching men age 25–34, who often remain undiagnosed or not virally suppressed.

The study explores key aspects of HIV-related norms, behaviours and beliefs among people living with HIV, including high-risk subpopulations. These key aspects include misinformation, service quality gaps, perceived treatment benefits and the impact of the Somos Iguais campaign.

Significantly more MLHIV who were on ART believed that HIV treatment reduces the risk of transmission compared with those who were not on ART (33% and 10%, respectively; p

While the study highlights a positive trend in HIV treatment literacy among MLHIV, it showed persistent stigmatising attitudes in the wider community. Investments to enhance knowledge and counter misconceptions about HIV treatment, especially among men not reached by the Somos Iguais campaign, are essential in expanding and sustaining the number of MLHIV virally suppressed on ART. Safeguarding patient confidentiality in clinics is imperative to encourage and sustain ART adherence.