Mathis studied and did an MD thesis in Germany. He worked in Berne (Liver Unit), Manchester and trained in hepatology (PhD in Liver Immunology) in Birmingham. He moved to Glasgow in 2007. He works as a Consultant Hepatologist in NHS Dumfries & Galloway and is Honorary Associate Clinical Professor (University of Glasgow). He pursues his research interests and is keen to improve public health and health inequalities through advocacy, and policy development for patients with liver disease.
He is Specialist Advisor to the Scottish Chief Medical Officer (liver) and to the Scottish Public Services Ombudsman. He is Vice Chair of Scottish Health Action on Alcohol Problems (SHAAP), advising the Scottish Government on Alcohol Policy and represents Scotland in the UK Liver Alliance.
He trained in quality improvement, coaching, negotiation, mediation and appraisal. He helped write BSG and NICE guidelines, and represents Scotland developing UK Alcohol Management guidance.