Mark has worked as a Clinical Nurse Educator with Takeda UK since 2020, providing education and training on ADHD from within the Takeda UK Neuroscience Medical Team. He had previously worked in the NHS since1995, and for 15 years was based in the South London & Maudsley NHS Foundation Trust's Adult ADHD & autism services. Outside of the NHS, Mark was on the steering and training committees of the UK Adult ADHD Network (UKAAN) for 10 years.