Depression is a common and complex disorder. The 1-month
prevalence rate for major depression is 2.6% and disorders occur
more frequently in women than men. The main symptoms are
feelings of sadness and/or the loss of enjoyment in activities
that were previously pleasurable. These features are unlike the
everyday mood changes that people experience in response to
normal stresses. They may persist for weeks and often months.
They may cause disruptions to the person’s ability to care for
themselves and cope at work, school/university or in their
relationships. Other symptoms include feelings of guilt or
worthlessness, suicidal ideas, concentration difficulties,
anxiety, sleep problems and appetite changes. All are seen as
the result of an interaction between biological vulnerabilities,
environmental factors (e.g. stressful events) and thinking
biases. The relative contributions of these differ from person
to person and even from episode to episode. In terms of
biological vulnerabilities, sometimes the person wi