The field of experimental psychology provides some excellent theoretical understanding about stress and depression. The key point from this theory is that events are considered psychologically stressful when they have some of the following characteristics\u2014a loss of control and predictability within certain contexts, a loss of outlets for frustration, a loss of source of support, a perception that in some aspects life is getting worse. In a number of experiments, when animals are subjected to stressful events that have these characteristics, the result is a condition similar to human depression.<\/p>\n
<\/p>\n
While the actual stressors may differ, the general approach in these studies always emphasizes repeated stressors with a complete absence of control on the part of the animal (for example in humans, people who have close friends or relatives who suffer from incurable diseases and are dying. The feeling of helplessness is most acute in such instances). After a while under such circumstances, the animal has trouble coping with day-to-day tasks. This phenomenon is called ‘learned helplessness’. This is similar to the depressed person who does not even try to perform the simplest task. Animals with learned helplessness also have a cognitive problem, something awry with how they perceive the world and think about it.<\/p>\n
To summarize, stress, particularly in the form of extremes of lack of control and outlets, causes an array of deleterious changes in a person\u2014<\/p>\n
\u2022 Cognitively, this involves a distortive belief that there is no control or outlets in any circumstances\u2014learned helplessness.<\/p>\n
\u2022 On the affective level, there is anhedonia-\u2014the threshold for pleasure is very high.<\/p>\n
\u2022 Behaviourally, there is psychomotor retardation.<\/p>\n
\u2022 On the neurochemical front, there are likely disruptions of serotonin, norepinephrine and dopamine signalling.<\/p>\n
\u2022 Physiologically, there are alterations in appetite, sleep patterns, pain perception, and sensitivity of the gluco-corticoids feedback system.<\/p>\n
Collectively all these array of changes are called depression. One key question about the stress-depression link is not fully answered: why is it that the stress-depression link uncouples after three or four bouts of depression? Remember our earlier discussion about depressive episodes taking on an internal rhythm of their own, independent of whether the outside world is pummelling you with stressors. There are a lot of theories that attempt to provide explanations but there is very little by way of actual data.<\/p>\n","protected":false},"excerpt":{"rendered":"