Diarmaid is a qualified Clinical Psychologist who obtained a Doctorate in Clinical Psychology in 2014 at Lancaster University, UK. Diarmaid also holds a B.A. (Hons), M.A., Higher Diploma in Education and a Conversion Diploma in Psychology. Diarmaid’s Doctorate in Clinical Psychology is fully recognised by the Department of Health under Directive 2005/36/EC and Diarmaid is a Chartered member of the Psychological Society of Ireland.

Prior to his clinical training, Diarmaid was a teacher for a number of years before moving to a managerial role with Acquired Brain Injury Ireland, a rehabilitation service for adults who have experienced an acquired brain injury. Following this, he worked as a psychology research assistant in Trinity College, Dublin and in St Patrick's University Hospital, Dublin in addition to a 12-month period as an Assistant Psychologist with the Talbot Group. The previous role involved engaging in psychological assessment and intervention with young people and adults with a range of presentations and needs, including autism, intellectual disability and mental health.

Diarmaid engaged with clients across the lifespan during his clinical training. Furthermore, since completing his Doctorate in Clinical Psychology he has worked with a range of teams within the Health Service Executive, including a Rehabilitation Mental Health Service, an Adult Mental Health Service and most recently as a Senior Clinical Psychologist with a Child Disability Team. Conducting autism assessments for children as part of a multidisciplinary team was central to Diarmaid's work in the latter role in addition to therapy and intervention with autistic adolescents and their families. Diarmaid is also highly experienced at administering multidisciplinary autism assessments within the private sector.

 When working therapeutically with clients Diarmaid draws on a range of models including Cognitive Behaviour Therapy (CBT), Cognitive Analytic Therapy (CAT), Dialectical Behaviour Therapy (DBT), Compassion Focussed Therapy (CFT) and Behaviour Models.