From a public health perspective, there is probably no more
important or daunting challenge than
reducing the prevalence of the most common mental disorders, namely anxiety
and depression.
These disorders have a combined community prevalence rate of between 15%
and
30% (Cox et al.
1987; Robins et al. 1991; Goldberg & Huxley, 1992; Kessler
et al. 1994; Meltzer et al. 1995) and
account for one-third of days lost from work due to ill health (Jenkins,
1985a) and one-fifth of all
consultations in general practice in the UK (Williams et al. 1986).
The common mental disorders
are associated with impairments in physical and social functioning at
least as severe those associated
with chronic physical illnesses (Wells et al. 1988; Klerman, 1989;
Wohlfarth et al. 1993; Ormel &
Costa e Silva, 1995; Spitzer et al. 1995; Martin et al.
1996),
and a mortality rate nearly twice that
of the general population (Murphy et al., 1987; Klerman, 1989;
Lloyd
et al. 1996). The public health
importance of these disorders, even in mild form, is further demonstrated
by the
finding that low
levels of depression resulted in 51% more days lost from work than major
depression (Broadhead
et al. 1990). The total annual cost of the common mental disorders
in
the UK may amount to £6
billion, of which two-thirds arises from lost productivity (Croft-Jefferys
& Wilkinson, 1989).
Despite the availability of simple, cheap and effective treatments (Paykel
& Priest, 1992; Effective
Health Care, 1993; Brugha, 1995), one study found that the prevalence of
these disorders in Britain
may have increased recently (Lewis & Wilkinson, 1993).