Challenging claims that mental illness has been increasing and mental well-being declining.

There has been a tendency by some social scientists and the media to claim that in advanced western societies like Britain and the US mental illness has been increasing and mental well-being declining over the period since the Second World War. In this paper I consider the evidence that is invoked in making such claims, along with the counter-evidence. In order to assess the evidence it is essential to take account of the different ways mental illness and mental well-being are measured and the definitions the measures embed. I argue that when the findings from studies using similar measures at different points in time are compared, there is little evidence of consistent secular increases in mental illness or declines in mental well-being. I suggest that such claims are encouraged by two main factors: first and most importantly, the major changes that have occurred in the official boundaries of mental disorder over the post-war period, which have also changed the ideas and perceptions of professionals and the public about mental health and illness; and second, the ready way in which data on mental health and illness can be used to support criticism of certain features of present-day society.