In Dr Neil Nedley’s Depression Hit Hypothesis: Identifying Depression and Its Causes, Dr Nedley and his team propose how certain lifestyle choices and non-modifiable factors can predict the development of depression. They identified 10 cause categories (hits or “blows” to the brain) and theorize that four or more active hits could trigger a depression episode. Identifying these factors and applying lifestyle therapies could play a very important role in the treatment of depressed individuals.