It is hoped that this research will provide valuable insights into the actual demography of the Twitter population in order to better inform future research and estimates of the population of people using Twitter. This would then provide valuable contextual information for ongoing research into social media use in the general population, and links to their mental health, which has so far been difficult to achieve due to the lack of reliable and available linked data. As well as this, the beginning of insights into the mental health of social media users, with an awareness of which groups those users represent, will orientate the direction of future research projects in the field of Mental Health Data Science and may provide early insights into possible causality. In summary, this project will provide a valuable basis for future research in Mental Health Data Science.