Depression is one of the most disabling medical
disorders. Depression is characterized by significant physiological
changes such as anorexia, constipation, insomnia, fatigue, lethargy,
gastrointestinal disturbances, dizziness or other faint body aches. According to WHO, depression is the 4th
leading cause of passing life with poor physical and mental health. The
productive life of depressed person decreased and his life moves towards early
death [1, 2]. Many studies were carried out to explore any relationship
between stressful life events and depression [3,4,5,6,7,8].
TYPES OF DEPRESSION
There are several types of classifications of depression but more simply
it is classified into two types: 1) endogenous depression 2) exogenous
Endogenous depression is characterized by changes in neurotransmitter
level in the synapses while depression arouses because of stress or tension was
called exogenous depression .
Physical, mental, or emotional
response to life events that cause mental tension is called stress. Stress is can
be caused by:
1) dependent events such as death of some dear
one, separation or threat of separation between very close relations can
generate great stress and weak nerves persons can not cope with it and
undergoes depression 
2) independent events e.g. widowhood,
and exposure to natural Disaster . Onset of depression relies
more on dependent events than independent events 
RISK FACTORS FOR DEPRESSION
External stressors (worse life experiences)
Genetic / Familial factors
Although external stressors (anything that induce/cause stress is called
stressor) are the primary trigger for start of depression episodes but
cannot be avoided since the rates of depression are higher among first-degree
biological relatives than in the general population . Less social contacts
in the family may also trigger depression in genetically predisposed
individual. It has been proved from twin pairs genetic studies that individuals
who have family history of depression can quickly develop depression when faced
stress in their life . Other individuals who do not have such familial or
genetic predisposing factors when experienced stress in life, show the symptoms
and biological markers of depression. Kendler et al., 1993  have studied direct effects of stressful life
events on depression. Chances of depression increase with life problems such as
divorce, financial problems, and being a crime victim . Severe life
stresses can show characteristics of depression within three to four weeks [14,
15] and can also trigger genetic risk factors that have strong correlation with
major depression . Other major risk factor for depression includes
negligence in early life years, early loss of one or both parents either by
separation or death, physical abuse .
BIOLOGICAL THEORIES OF DEPRESSION
Several theories for depression have been proposed. Depression is due to
genetic as well as biological changes in depressed individual. Studies of
genetics, twin cohorts, and neurotransmitters, over the past 30 years, have
given an idea that genetic changes or familial component are the causes of
depression. To study neurotransmitters, three different approaches have been
used: 1) A deficiency model, 2) An imbalance model, and 3) the systems
dysregulation model 
According to the deficiency model, the depression was
related to the deficiency of norepinephrine (NE), however, the latest theories
proposed some complexity in arousal of depression . An imbalance model theory states that depression is due to an imbalance between levels of NE
and acetylcholine. Dysregulation model is
the most advance theory and according to it the depression is due to
dysregulation of cortisol level in the body .
Stress theory was coined to prove that there is a mood disturbance in
depression which is caused by stress in life. According to a study, depressed
patients started to exaggerate their life events at least six months before the
onset of depressive episodes as compared to control groups .
There are few studies which claimed social support can help patient to
get rid of stress, on the other hand low social support can generate sense of
failure or low self esteem in at risk persons but according to Vilhjalmsson, 1993
; Brown and Harris 1978 , there is no clear role of social support in
the relationship between stress and depression.
COGNITIVE THEORIES OF DEPRESSION
This theory supports the hypothesis that hopelessness, reflecting the
victim’s belief that negative events will persist . Seligman suggested that
animal models of learned helplessness can present the picture of depression .
The psychodynamic perspective concludes that depression is not an organic
disease, but it is a defense by the ego against intra-psychic conflict .
The core presumptions of this theory include:
depression is mainly due to some early life defect,
such as the loss of a parent
bad life experiences such as divorce or loss of a job
can provoke depression episodes
helplessness and hopelessness are the major
contributing factors to depression
ambivalence toward love objects is fundamental to the
emotional issues at hand;
Loss of self-esteem is an important feature of
METHODS TO STUDY RELATIONSHIP
BETWEEN STRESS AND DEPRESSION
Two methods were used for this study a) life events checklist b) and interview
method . However, McQuaid, 2000  and Simons et al., 1993  found that the interview methods are more
effective in predicting outcomes (depression) as compared to the interview
CLINICAL STUDIES DEMONSTRATING THE
RELATIONSHIP BETWEEN STRESS AND DEPRESSION
Studies reported based on control group and research group (depressed
patients) that great stress can initiate depressive episodes in patients as
compared to the control group [4, 26]. Mazure, 1998  reported that the major
stressful life events can cause depression in 80% individuals and depressed
patients experienced 2.5 times more stress as compared other study groups. Although
stress plays major role to induce depression but there has been found that
individual’s genetic risk factors also influence major depression episodes .
In one clinical study, follow up cases of patient were categorized into
three groups; a) medical illness b) bipolar (mood swings in two directions, in
this depression alternates with mania) disorder, c) no disorder and were
compared with a clinical sample of patients with histories of recurrent
unipolar depression. In this research, the term “stress generation” was coined
to present the conclusion. It was concluded that recurrent unipolar depression
patients had to face extreme stress due to dependent events of life. Therefore,
this study proves that the dependent events are more predictive of depression
episodes . The relationship between stress generation and major depression
had been replicated in various studies, including community samples of late
adolescent women , adolescent males and females [29, 30], , adult men  and
women [32, 33], children of depressed mothers  and clinical samples of
children and adolescents [35, 36] and adults . Most of these studies revealed
that the elevated rates of stressors among those with depression histories did
not occur for independent (fateful) events, and were specific to the dependent
events that were especially likely to reflect interpersonal content.
Stressful life events can move an individual towards depression. Stressful
life events can arouse genetic risk factors that are positively correlated with
major depression. It is concluded that risk factors of depression (genetics, early
life stress, such as childhood ignorance, early loss of parents, physical or
sexual abuse) and ongoing life stresses may ultimately lead to depression.
- WHO report, 2001. Mental Health: New Understanding, New Hope.
- Evans, D.L and D.S. Charney, 2003. Editorial:
Mood disorders and medical illness: A major public health problem. Biological
Psychiatry, 54: 177–180.
- Kessler, R.C. 1997. The effects of stressful
life events on depression. Annual
Review of Psychology, 48: 191–214.
- Mazure, C.M. (1998). Life stressors as risk
factors in depression. Clinical Psychology Science and Practice, 5:
S.M and K. Hadjiyannakis, 2002. The social environment and depression:
focusing on severe life stress.
Gotlib and Hammen, pp 314-340.
- Paykel, E.S. 2003. Life events and affective
disorders. Acta Psychiatrica
Scandinavica, 108: 61–66.
- Tennant, C. 2002. Life events, stress and depression:
a review of the findings. The Australian and New zeeland Journal of
R.E and L.B. Alloy, 2011. Life stress and kindling in bipolar
disorder: review of the evidence and integration with emerging
biopsychosocial theories. Clinical
Psychology Review, 31(3): 383-98.
- Calarco, M and K. Krone, 1991. An integrated nursing model of depressive
behavior in adults. The Nursing
Clinic of North America, 26:
K.S; L.M. Karkowski and C.A. Prescott,
1999. Causal relationship between stressful life events and the onset of major
depression. American Journal of Psychiatry,
- Barlow, D.H and V.M. Durand, 1995. Abnormal
Psychology: An Integrative Approach. 4th ed. Pacific Row, Calif: Brooks/Cole.
- Kendler, K.S; R.C. Kessler; M.C. Neale; A.C.
Heath and L.J. Eaves, 1995. Stressful life events, genetic liability, and
onset of major depression in women. American Journal of Psychiatry, 150:
- Kendler, S.K; R.C. Kessler; M.C. Neale; A.C. Heath
and L.J. Eaves 1993. The prediction of major depression in women: towards
an integrated etiological model. American
journal of psychiatry, 150: 1139-1148.
- Brown, G.W and T.O. Harris, 1978. Social Origins of Depression: A Study
of Psychiatric Disorder in Women. New York, NY:
The Free Press.
- Hammen, C 1991. Generation of stress in the
course of unipolar depression. Journal of Abnormal Psychology, 106:
- Kendler, K.S; L.M. Karkowski and C.A. Prescott,
1998. Stressful life events and major depression: risk period, long-term
contextual threat and diagnostic specificity. The Journal of Nervous
and Mental Disease, 186: 661–669.
- Kendler, K.S; L.M. Thornton and C.A.
2001. Gender differences in the rates of exposure to stressful life events
and sensitivity to their depressogenic effects. American Journal of
S.M; K.L. Harkness, 2005. Life stress, the `kindling' hypothesis, and the
recurrence of depression: considerations from a life stress
- Stuart, G and S. Sundeen, 1995. Principles and Practice of Psychiatric
Nursing. 5th ed. St. Louis, Mosby.
- Vilhjalmsson, R 1993. Life stress social support
and clinical depression: A Reanalysis of the literature. Social Science
and Medicine, 37: 331-342.
- Abramson, L; G. Metalsky and L., Alloy, 1989. Hopelessness
depression: A theory-based subtype of depression. Psychological Review,
- Seligman, M.E.P 1975. Helplessness: On Depression Development and Death. San Francisco, Calif:
- Bootzin, R; A. Ross and L. Alloy, 1993. Abnormal Psychology Current
Perspectives. New York,
NY: McGraw- Hill.
- McQuaid, J.R; S.M. Monroe; J.E. Roberts; D.J.
Kupfer and E. Frank, 2000. A comparison two life stress assessment
approaches: prospective prediction of treatment outcome in recurrent
depression. Journal of Abnormal
Psychology, 109: 787–791.
- Simons, A.D; K.L. Angell; S.M. Monroe and M.E. Thase,
1993. Cognition and life stress In depression: cognitive factors and the
definition, rating, and generation of negative life events. Journal of
Abnormal Psychology, 102: 584–591.
- Brown, G.W and T.O. Harris, 1989. Depression.
In: Life Events and Illness, New York:
- Kendler, K.S and L. Karkowski-Shuman, 1997.
Stressful life events and genetic liability to major depression: Genetic
control of exposure to the environment. Psychological Medicine, 27: 539–547.
- Heim, C and C.B. Nemeroff, 2001. The role of
childhood trauma in the neurobiology of mood and anxiety disorder:
Preclinical and clinical studies. Biological
Psychiatry, 49: 1023-1039.
- Hammen, C and P.A. Brennan, 2001. Depressed
adolescents of depressed and nondepressed mothers: tests of an
interpersonal impairment hypothesis. Journal of Consulting and Clinical
Psychology, 69: 284–294.
- Daley, S.E;
N. and D.S. 1997. Predictors of the generation
of episodic stress: a longitudinal study of late adolescent women. Journal of abnormal psychology,
- Patton, G.C;
and G. Bowes,
2003. Life events and the early
onset depression: cause or consequence? Psychological Medicine, 33:
- Cui, X.J and G.E. Vaillant, 1997. Does depression
generate negative life events? The Journal of Nervous and Mental Disease,
- Hammen, C and P.A. Brennan, 2002. Interpersonal dysfunction in
depressed women: impairments independent of depressive symptoms. Journal
of Affective Disorders, 72: 145–156.
- Harkness, K.L and L. Luther, 2001. Clinical risk
factors for the generation of life events in major depression. Journal
of Abnormal Psychology, 110: 564–572.
- Adrian, C and C. Hammen, 1993. Stress exposure
and stress generation in children of depressed mothers. Journal of
Consulting and Clinical Psychology, 61: 354–359.
- Rudolphm, K.D and C. Hammen, 1999. Age and
gender as determinants of stress exposure, generation, and reactions in
youngsters: a transactional perspective. Child Development, 70:
- Rudolph, K.D; C. Hammen; D. Burge; N. Lindberg;
D. Herzberg and S.E. Daley, 2000. Toward an interpersonal life-stress
model of depression: the developmental context of stress generation. Development
and Psychopathology, 12: 215–234.