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Additional research data indicate that people suffering from depression have imbalances of neurotransmitters, natural substances that allow brain cells to communicate with one another. Two transmitters implicated in depression are serotonin and norepinephrine. Scientists think a deficiency in serotonin may cause the sleep problems, irritability, and anxiety associated with depression. Likewise, a decreased amount of norepinephrine, which regulates alertness and arousal, may contribute to the fatigue and depressed mood of the illness.
Other body chemicals also may be altered in depressed people. Among them is cortisol, a hormone that the body produces in response to stress, anger, or fear. In normal people the level of cortisol in the bloodstream peaks in the morning, then decreases as the day progresses. In depressed people, however, cortisol peaks earlier in the morning and does not level off or decrease in the afternoon or evening.
Researchers don't know if these imbalances cause the disease or if the illness gives rise to the imbalances. They do know that cortisol levels will increase in anyone who must live with long-term stress.
2. Explain the environmental causes of depression
Certain environmental situations, such as stress or breakup of important attachments, also may precipitate depression, especially in vulnerable persons.
Research continues to better understand the interaction of genes and environment, and precisely what is inherited.
3. Explain the cognitive causes of depression.
Cognitive theories rose to prominence in response to the early behaviorists' failure to take thoughts and feelings seriously. The cognitive movement did not reject behavioral principles, however. Rather, the idea behind the cognitive movement was to integrate mental events into the behavioral framework. Cognitive Behavioral theories (sometimes called "cognitive theories") are considered to be "cognitive" because they address mental events such as thinking and feeling. They are called "cognitive behavioral" because they address those mental events in the context of the learning theory that was the basis for the pure behavioral theory described above. The rise in popularity of cognitive behaviorism continues today; it forms the basis of the most dominant and well-research formed of psychotherapy available today: Cognitive-Behavioral Therapy, or CBT.
Cognitive behavioral theorists suggest that depression results from maladaptive, faulty, or irrational cognitions taking the form of distorted thoughts and judgments. Depressive cognitions can be learned socially (observationally) as is the case when children in a dysfunctional family watch their parents fail to successfully cope with stressful experiences or traumatic events. Or, depressive cognitions can result from a lack of experiences that would facilitate the development of adaptive coping skills.
According to cognitive behavioral theory, depressed people think differently than non-depressed people, and it is this difference in thinking that causes them to become depressed. For example, depressed people tend to view themselves, their environment, and the future in a negative, pessimistic light. As a result, depressed people tend to misinterpret facts in negative ways and blame themselves for any misfortune that occurs. This negative thinking and judgment style functions as a negative bias; it makes it easy for depressed people to see situations as being much worse than they really are, and increases the risk that such people will develop depressive symptoms in response to stressful situations.
4. Explain the "cognitive triad" as it relates to depression.
Beck's cognitive triad is a triad of types of negative thought present in depression proposed by Aaron Beck in 1976. The triad forms part of his Cognitive Theory Of Depression.
The triad involves negative thoughts about:
- The self (i.e., self is worthless)
- The world/environment (i.e., world is unfair), and
- The future (i.e., future is hopeless).
http://en.wikipedia.org/wiki/Beck's_cognitive_triad
