Dr Gayan Perera is an experienced epidemiologist with research interests in mental health, primary care, public health, clinical informatics, medical law, and health service evaluation, having authored over 100 peer-reviewed publications and book chapters.His doctoral research was focused on health outcomes and treatment response to dementia, including response to acetylcholinesterase inhibitors. Since then, he has gone on to develop epidemiological methodology to investigate cognitive response to centrally acting ACE inhibitors and trazodone among patients with dementia using real-life observational data. He also worked on large international research databases and worked in the pharmaceutical industry at Roche Products Ltd in the EMIF-AD project, which established a pan-European platform for large-scale research on biomarkers and risk factors for neurodegenerative disorders. He expanded his interest in epidemiology, working on mental health data linked to other data sources, such as cancer and primary care records, and has investigated associations between physical health and mental health problems. By working with the physical health and mental health interface, he gained experience in the preventative elements in public health, and he was interested in how wider determinants of health, such as loneliness and non-employment, affect mental health. To do this, he used local mental health data as well as nationally representative surveys such as the Adult Psychiatric Morbidity Survey (APMS).

During the COVID-19 pandemic, he investigated the impact of the pandemic on older people's mental health services. Furthermore, he investigated antidepressant drug prescriptions and the incidence of COVID-19 in mental health. He has experience in leading research into inequalities and has led a multi-professional research group looking at surgical outcomes among patients with mental health problems and investigated outcomes after vascular surgery, bariatric surgery and cardiac surgeries. He has a growing portfolio of mental health law research and has particularly focused on community treatment orders and the Mental Health Act 1983, affecting patient outcomes.

Dr Gayan Perera has a background in public health and clinical informatics and is an honorary Member of the Faculty of Public Health (MFPH) through distinction. He has led various health intelligence functions in Primary Care Trusts (PCTs), NHS England, and local authorities.  He teaches in undergraduate and postgraduate public health and mental health programmes.  He is a module leader on the MSc Mental Health Studies and on the MSc Public Health programmes. He teaches on the Big Data module. He is a PhD supervisor as well as an MSc dissertation supervisor and is a member of the Psychological Medicine PhD sub-committee at King's College London.  

He is also admitted and enrolled as an Attorney-at-Law of the Supreme Court of Sri Lanka.