Trefor joined the psychology department in Aberystwyth as a lecturer in 2019. His research, in the areas of health and clinical psychology, includes research on the framing of health promotion messages, and in the use of talking therapies for treating depression and anxiety.

Trefor obtained his PhD from Bangor University in 2010, looking at health related behaviours, message framing and motives. After obtaining his PhD he went on to work in Royal Holloway University as a research assistant and later as a trial manager. Prior to joining the psychology department here in Aberystwyth, Trefor worked in University College London for five years as a senior research associate. During his time in UCL, he managed two randomised controlled trials looking at the effectiveness of Cognitive Behavioural Therapy for depression in patients with advanced cancer, and in older victims of crime. Whilst at UCL Trefor also gained experience lecturing on the Clinical Mental Health Sciences MSc course.