Very reasonably, a couple of people have raised an eyebrow at the statistics I quoted in my blog items over the last couple of days about the prevalence of mental health issues. These statistics are incredibly difficult to establish and to verify, and there are so many different variations on a theme that it becomes impossible to draw comparisons. Worse still, they are often appallingly badly cited in the press.
The criteria still vary (and surveys are very expensive to conduct so they aren’t repeated all that often) but the definitions are slowly coalescing on reasonably clear terms. Thus ‘diagnosable mental health problem’ will often mean a set of symptoms that would have led someone to be assessed using one of the two main diagnostic schemes (DSM-IV or ICD 10) as meeting the criteria for a particular condition.
Some statistics, such as the UK ones, are mainly based on such assessments being performed by a medically qualfied practitioner, of a patient who has presented because the patient is concerned by their own condition. These will obviously report a lower percentage of the population as a whole.
Other statistics, such as some of the US ones, are based on the completion of a questionaire by an individual without help, and may ask specifically whether the person has been diagnosed or give a list of possible symptoms which the researchers then interpret.
Finally, the NZ survey referred to below, had interviewers work through a questionaire of symptoms with the individuals. This is going to yield one of the highest percentages.
I have no desire to become an authority on the statistics – my role involves working with very senior leaders who experience, and may even depend on, some form of mental health condition during their working day.
However, just to give you a few ‘factoids’…
- 1 in 3 British adults experience at least one diagnosable mental health problem in any one year. ((Source: Goldberg, D. & Huxley, P, 1992, Common mental disorders a bio-social model, Routledge.)
- In 2007, 1 in 4 people (23.0 per cent) in England experienced at least one psychiatric disorder and 7.2 per cent had two or more disorders. (Source: Adult Psychiatric Morbidity in England, 2007)
- 1 in 6 British adults experience at least one diagnosable mental health problem at any given time. (Source: The Office for National Statistics Psychiatric Morbidity report, 2001)
- 1 in 10 British children between the ages of 5 and 15 have experienced at least one diagnosable mental health problem. (Source: Survey of the Mental Health of Children and Adolescents, Office for National Statistics, 1999)
- 1 in 2 (50.8%) US citizens experience a mental health disorder in the course of their life. (Source: The National Comorbidity Survey Replication (NCS-R))
- More than 50% of the people in Dunedin, New Zealand, had suffered from mental illness at least once by the age of 32. (Source: Te Rau Hinengaro: The New Zealand Mental Health Survey, 2006)
- In New Zealand, 39.5% of people aged 16 and over met the criteria for a disorder at some time before interview. (Source: Te Rau Hinengaro: The New Zealand Mental Health Survey, 2006) [This was a comprehensive survey, conducted particularly rigourously, and as it was representative of the population as a whole, it was possible to estimate statistically that more than 46.6% will have done so by the age of 75.]
I hope that gives you enough to see where I got my figure from. The range of possible disorders is very wide. As I said before, to me the issue is whether the individual’s experience of life is diminished before, during or after the episode of their mental health condition. I have also made the point that some conditions actually enhance performance for prolonged periods of time. In the longer term though, this may not be sustained and could have more serious consequences than it would have, had it been recognised and addressed earlier.