Question: In your profile you said you study why teenagers act the way they do, but is that for all of them because surely they act by the way there surroundings are and what people do to make them act that way, right?

Alex Spiers answered on 13 Nov 2019:

When epidemiologists study behaviour – we are looking for patterns in populations. This means we are looking for average behaviour, or trends in the population. This allows us to asses whether risk factors (e.g. smoking, not exercising, bullying) might affect health outcomes (e.g. depression, stress). However, we can never predict exactly how a person might behave. As you say, it is often a person’s surroundings that make people behave the way they do – and its different for everyone!