depression - background information
This handout gives background information about depression. The main messages are that
depression is very common but unfortunately is often not recognised. Encouragingly once the
diagnosis is made, there are many effective treatments available. The information is intended
primarily for depression sufferers and their families. At times it is somewhat concentrated and
technical, so don’t feel you have to take it all in at once. Note points that seem relevant to you.
You can then discuss them with your doctor or therapist. General health professionals may also
find the handout of interest. The main points covered are:
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what is depression?
how common is it?
what causes depression?
how long does it go on for?
 what is depression?
The word depression is used to cover a whole spectrum of states from brief everyday feelings of
unhappiness to profoundly disabling and life-threatening medical disorders. When a health
professional talks about depression, the following nine symptoms1 are considered particularly
relevant:
1.) depressed mood most of the day, nearly every day (as indicated by subjective report or
observation by others) – in children and adolescents can be irritable mood.
2.) markedly diminished interest or pleasure in all, or almost all, activities most of the day,
nearly every day (as indicated by subjective account or by others).
3.) significant weight loss when not dieting or weight gain (e.g. a change of more than 5% of
body weight in a month), or decrease or increase in appetite nearly every day.
4.) insomnia or hypersomnia nearly every day.
5.) psychomotor agitation or retardation nearly every day (observable by others).
6.) fatigue or loss of energy nearly every day.
7.) feelings of worthlessness or excessive or inappropriate guilt nearly every day (not just selfreproach or guilt about being sick).
8.) diminished ability to think or concentrate, or indecisiveness, nearly every day (either by
subjective account or as observed by others).
9.) recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without
specific plan, or a suicide attempt or a specific plan for committing suicide.
To be diagnosed as suffering from a major depressive episode, one would need to have suffered
from five or more of these symptoms – including (1.) and/or (2.) – over the same two week
period. Symptoms that are clearly due to a general medical condition should not be counted.
A companion handout “Diagnosing depression” gives more detail about specific diagnoses such
as major and minor depression, dysthymia, recurrent brief depression, manic/bipolar depression,
and seasonal affective disorder. Clarifying the diagnosis is important in deciding what form of
treatment is likely to be most effective.
Obviously just about everyone feels a bit low and depressed occasionally. This is part of the ups
and downs of everyday life. If however you suffer persistently or recurrently even from only
one or two of the nine symptoms, then this is a message it is likely to be worth doing something
about. Mild subsyndromal depressions are associated with increased unhappiness, health
complaints, social dysfunction and work disability2. They also signal considerably greater risk of
developing more serious psychological disorders in the future3. It is better to put out fires while
small rather than wait till they are blazing.
[cont.]
 how common is it?
About I in 5 of us will experience a major depressive episode at some stage in our lives4. In
fact about 1 in 20 of us is suffering from a major depressive episode right now. Recurrent brief
depression (RBD) – as severe as major depression, but the individual episodes are shorter &
more frequent – has a lifetime prevalence of about 1 in 65. Similarly dysthymia – low grade
depression going on for years – affects about 1 in 15 of us at some point4. Obviously these
syndromes overlap and we may suffer from different types of depression at different stages in
our lives. Staying with the formal diagnoses of dysthymia, minor depression, RBD and major
depression, more than 1 in 3 of the population will suffer from one or more of these disorders
during their lifetime6.
Worryingly people are developing their first major depressive episode at progressively younger
ages7. This does not just seem to be due to a greater willingness to report symptoms, as
suicides and hospitalisations are also increasing in the young8. In fact research on current
major depression by decade of age found the highest rate in the youngest age group studied9.
Women especially have an enormous liability to depression onset in the second half of their
teens. A further survey10 found that 50% of those with a history of major depressive episode
had first onset by age 25. Traditionally depression has affected women much more than men,
but this is changing. For example in 1980 the male admission rate to Scottish hospitals for
depression was only half the female rate. By 1995 this ratio had increased to two thirds11.
 what causes depression?
Just as panic disorder is based on inappropriate firing of primitive alarm fight or flight responses,
so depression can be viewed as a distorted form of what was an evolutionarily adaptive
withdrawal & re-evaluation response12,13. Emotions are crucially important in helping us to
decide what to do. Clearly there are repeated times during our lives when goals or intentions
we had turn out to be unattainable or outdated. For survival, humans need mechanisms that
help them disengage from such situations. Feelings of frustration, unhappiness and even
despair may well be telling us that our progress towards desired goals seems too slow or is
blocked entirely14. This can usefully trigger a biologically programmed retreat-review-redirect
reaction. Unfortunately there are times when our hopes have been dashed, but we also feel
unable to let go and move on. This blocked disengagement reaction can form the basis of
depression.
This way of understanding depression however is just one aspect of a more complex overall
model that needs to integrate factors such as life events & difficulties, coping behaviour,
cognitive style, interpersonal factors, genetics and childhood experience. It is often helpful to
distinguish vulnerability factors, triggering factors and maintaining factors. See the companion
handout “Why do we get depressed?” for an illustration of this. Upbringing and heredity
contribute to an individual’s coping style, life situation and overall vulnerability to depression.
Traumatic events and other types of trigger may then act to precipitate a depressed mood. How
we respond to this experience – our behaviours, biology, thoughts and relationships – contribute
towards maintaining or recovering from this depressed state.
It is important to remember as well that depressive symptoms can be caused or worsened by
other illnesses and difficulties. Examples include underactive thyroid, anaemia, medical
disabilities and alcoholism. There are often also additional psychological problems4 such as
panic attacks, obsessive compulsive symptoms, eating disorders, and dysfunctional coping
styles.
 how long does depression go on for?
The issues of duration and recurrence of depression are very important. Nearly all episodes of
depression do eventually get better15. Frequently though depression tends to recur. [cont.]
As stated on the first page of this handout, even quite mild symptoms of depression are well
worth tackling. However we should focus particular treatment efforts on depressions that are
severe or not getting better quickly enough or that have a high likelihood of recurrence.
Research in hospital outpatient departments shows that approximately 40% of people treated
for major depression will recover within 3 months, about 60% within 6 months, and about 80%
within a year15. Those with major depression who are treated by non-specialist health care
professionals may do considerably less well16,17 with possibly only 20% fully recovered at 8
months18,19. Happily specialist care seems less important for more minor depressions16. Despite
a slowing of recovery rate with increased episode severity20 and duration, virtually all major
depressive episodes do eventually remit15. Clearly by definition recovery rates are rather
different for other types of depression like dysthymia and RBD. Interestingly if someone gets a
series of recurrent major depressive episodes, all of them tend to last similar lengths of time –
unless of course one catches subsequent attacks and treats them more quickly. Overall these
findings on recovery rate are fairly encouraging. Less welcome are the research studies on
relapse and recurrence.
Typically relapse is defined as a return of major depression following incomplete recovery or
after recovery that lasted less than six months21. Recurrence usually describes new episodes of
major depression occurring after at least six months of recovery. Unfortunately the majority of
those seen at hospital outpatient departments for major depression will experience at least one
recurrence. This risk decreases the longer one stays recovered. One major research study22
found that 40% of outpatient recoveries relapsed by 1 year, 54% by 2 years and 76% by 5
years. Further research23 on those with more severe depression suggests they will experience
an average of 5 or 6 depressive episodes in their lifetime and may spend as much as 20% of
their time in a depressed state24. One of the strongest predictors of relapse is the number of
previous episodes25. Also at high risk of relapse are those with “double depression”22 – a major
depressive episode superimposed on pre-existing dysthymia (both these risk factors should
become evident on discussion). Care should be taken too to monitor for persisting residual
symptoms after recovery (see the list of symptoms on page 1, and check the BDI score). As
many as a third of those with major depression may only make a partial recovery26 and this
increases the risk of relapse. As one might predict from the earlier section on “What causes
depression?”, genetic factors27 (evident from the family history), difficult early childhood
experiences28,29(see the Traumatic events checklist and the PBI), social adversity30(see the
Checklist of potential problem areas), coping & personality difficulties31(discuss Problem solving),
quality of support in close relationships4,32(see the Degree of partner criticism scale, the Dyadic
adjustment scale and the IBM), and poor social adjustment33 (see the Social adjustment scale)
all also suggest more care should be taken subsequently to monitor for familiar early symptoms
that warn depression may be returning. Early recognition and prompt treatment are very
helpful34.
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