4.4 Are women more likely to suffer from anxiety disorders than men?
Before we proceed further, it is important first to establish the concepts of prevalence, incidence and lifetime prevalence, which are frequently used when figures are quoted for mental health conditions – see Box 9. DALYs and YLDs, which you were introduced to in Section 3, are also defined here for reference.
Box 9 Understanding the figures frequently quoted for mental health conditions
Prevalence – the number of people with a particular diagnosis within the population at any given time.
Lifetime prevalence – the number of people who have experienced a particular mental health problem at any time in their lives.
Point prevalence − the number of new and pre-existing cases at a specified point in time (i.e. the number of people living with a condition within a specified time period, e.g. one year, divided by the number of individuals within the population).
Incidence – the number of new cases of a particular mental health condition that appear in a specified time period.
DALYs – disability-adjusted life years or the sum of years of potential life lost due to premature mortality and the years of productive life lost due to disability.
YLDs – years lived with disability.
Comparing the number of new cases (incidence) with the number who are ill at any given time (prevalence) can provide a rough indication of the average amount of time a mental health condition is likely to last. Often the number of people treated by health professionals is used to determine how common a mental health problem is, but this is likely to be an underestimate as it does not take into account those who may not have come into contact with services. Psychiatric diagnoses are also not always straightforward as we have seen, and a person’s diagnosis can change during the course of their life, and impact on the treatment that they receive.