Causes of Clinical Depression
Depression may be partly associated with personality disorder
and psychological sensitivity as noted above, or it may be mostly
biological as will be discussed in this section. Biological
depression may make one’s personality seem more disordered and
vice-versa. Many persons with depression often conclude there was
a problem in their upbringing, and maybe there was, but often
they confuse meaning and cause. Any significant life event of
course has meaning for the person, but it may not be the
cause of the problem. Most persons with tough childhoods
don’t get depression; but if you have both it is easy to make
cause and effect conclusions.
While the details are beyond the scope of this web site,
there are also an enormous number of studies and findings on the
biologic nature of depression. For example, if you put the search terms,
"genetics of depression", or "serotonin transporter in
depression", or "brain scans in depression", or "neurobiology
in depression", etc. into the Pub Med web
site of the U.S. National Library of Medicine or other search engine, you will find an extensive literature related to biologic findings in depression.
A consistent finding is that of overactivity in the hypothalamic-pituitary-adrenal (HPA) axis (possibly from stress) leading to increased tone of the sympathetic nervous system that then causes the release of cytokines (substances usually released when there is some inflammation) that promote the development of depression. Another is that a deficiency of neurotrophic factors that help the growth and survival of nerves in an area of the brain called the hippocampus can lead to depression. Antidepressants are known to normalize the HPA axis, and also to increase the production of neurotrophic factors.
Some researchers have found that persons
with one type of genetics (the short form of the serotonin
transporter allele) are more sensitive to developing depression
secondary to outside stress compared to those without these
genetics. This suggests (but not proven yet) that there may be interaction between environment and
heredity, but again, as most persons would not get depressed with
this kind of stress, it is not unreasonable to see the major
cause as biologic in nature. Otherwise, it would be like saying
that eating chocolate cake interacts with genes in those susceptible to diabetes so
that diabetes is not due to a biologic cause. Finally, molecular biology studies are beginning to show that specific "molecular signatures" may be found in persons with depression.
Types of Clinical Depression
This discussion assumes there is no substance use involved.
Persons who use cocaine, ecstasy, LSD, and other substances may
induce a mood disorder in themselves, the characteristics of
which may differ from the discussion below and are beyond the
scope of this web site.
Dysthymia (Persistent Depressive Disorder)
Dysthymia is a chronic mild depression. It has
a lifetime Risk of 6%. These persons often come for treatment
when their depression gets worse, and sometimes when something
happens that forces them to see that their moods and energy
levels are seriously impairing their ability for success. Most of
the ideas noted in the clinical depression section above also
pertain to dysthymia.
Recurrent Brief Depression
Recurrent Brief Depression (RBD) is defined as short-duration (less then 14 days, usually 2-3 days) of depressive episodes occurring at least once a month over at least one year, not related to menses in women. These episodes may be severe, have associated anxiety, irritability and over-sleeping. The lifetime prevalence of RBD has not been clearly established because studies did not clarify RBD with and without a history of other mood disorders, however, the DSM-IV field trial estimated the life-time of RBD only to be about 2%.
Many persons seen in the Counseling Tokyo offices have on and off short periods of depression, often concluding that they are part of their personality or circumstances, not seeking help until they have a more severe episode. The frequent nature of RBD occurring in a variety of circumstances indicates that the brain areas disturbed are probably set in a cyclical fashion like many other parts of human neurologic function (e.g., sleep-wake cycles, brain control of hormonal cycles, body temperature cycles, etc., called circadian rhythms).
Persons with Atypical Depression usually have overeating instead of a decrease in appetite, oversleeping instead of insomnia, ability to feel some degree of enjoyment in response to positive events, and may show a high sensitivity to being rejected. Actually, a large percent of persons with a diagnosis of depression may exhibit these kinds of symptoms.
The trouble with having this type of depression is that is is often overlooked by both the patient and the therapist as a eaction to stress or a Personality Disorder. Patients with atypical depression may languish in psychotherapy for years with a diagnosis of personality disorder only to find that antidepressant medication finally helps them significantly. Note that both the typical and atypical types of depression may be associated with high levels of irritability instead of depressed mood per se. An astute psychiatrist might diagnose depression in someone who most persons see as only "cranky".
Go to depression page three.
Summary of Depression Links:
Cognitive Therapy ｜
Serotonin Transporter Allele｜
Molecular Biology Studies｜
Recurrent Brief Depression｜
bipolar disorder (Manic Depression)｜
Diagnostic and Statistical Manual of Mental Disorders-IV｜
Post-Partum Depression ｜
Premenstrual Dysphoric Disorder｜