Three Types of Depression
The three main categories of depression are
major depression, dysthymia, and bipolar depression
(sometimes referred to as manic depression).
Major depression affects 15 percent of Americans
at one point during their lives, according to
the U.S. Department of Health and Human Services.
Its effects can be so intense that things like
eating, sleeping, or just getting out of bed
become almost impossible.
Major depression "tends to be a chronic,
recurring illness," Laughren explains.
Although an individual episode may be treatable,
"the majority of people who meet criteria
for major depression end up having additional
episodes in their lifetime."
Unlike major depression, dysthymia doesn't
strike in episodes, but is instead characterized
by milder, persistent symptoms that may last
for years. Although it usually doesn't interfere
with everyday tasks, victims rarely feel like
they are functioning at their full capacity.
According to the National Alliance for the Mentally
Ill, almost 10 million Americans may experience
dysthymia each year.
Finally, bipolar disorder cycles between episodes
of major depression and highs known as mania.
Bipolar disorder is much less common than the
other types, afflicting about 1 percent of the
U.S. population. Symptoms of mania include irritability,
an abnormally elevated mood with a decreased
need for sleep, an exaggerated belief in one's
own ability, excessive talking, and impulsive
and often dangerous behavior.
Depression - Genes and Environment
Study after study suggests biochemical and
genetic links to depression. A considerable
amount of evidence supports the view that depressed
people have imbalances in the brain's neurotransmitters,
the chemicals that allow communication between
nerve cells. Serotonin and norepinephrine are
two neurotransmitters whose low levels are thought
to play an especially important role. The fact
that women have naturally lower serotonin levels
than men may contribute to women's greater tendency
Family histories show a recurrence of depression
from generation to generation. Studies of identical
twins confirm that depression and genes are
related, finding that if one twin of an identical
pair suffers from depression, the other has
a 70 percent chance of developing the disease.
For fraternal twins or siblings, the rate is
just 25 percent.
Environmental factors, however, may also play
a role in depression. When combined with a biochemical
or genetic predisposition, life stressors (such
as relationship problems, financial difficulties,
death of a loved one, or medical illness) may
cause the disease to manifest itself.
John (not his real name), 25, was diagnosed
with depression for the first time last year
when he and his girlfriend ended their three-year
relationship. "I couldn't do anything because
I was totally absorbed with the whole break-up
issue," he says. "It was impossible
for me to sleep, and I would wake up at 3 or
4 in the morning and literally shake. And when
it was time to wake up, I just couldn't get
out of bed."
In addition, substance abuse and side effects
from prescription medication may also lead to
a depressive episode. And research shows that
people battling serious medical conditions are
especially prone to depression. According to
the U.S. Department of Health and Human Services,
those who have had a heart attack, for example,
have a 40 percent chance of being depressed.
Seasonal affective disorder, often called "SAD,"
is a striking example of an environmental factor
playing a major role in depression. SAD usually
starts in late fall, with the decrease in daylight
hours and ends in spring when the days get longer.
The symptoms of SAD, which include energy loss,
increased anxiety, oversleeping, and overeating,
may result from a change in the balance of brain
chemicals associated with decreased sunlight.
The exact reason for the association between
light and mood is unknown, but research suggests
a connection with the sleep cycle. Several studies
have suggested that light therapy, which involves
daily exposure to bright fluorescent light,
may be an effective treatment for SAD.
Depression - Diagnosing the
Medical professionals generally base a diagnosis
of depressive disorder on the presence of certain
symptoms listed in the American Psychiatric
Association's Diagnostic and Statistical Manual.
The DSM (presently in the fourth edition) lists
the following symptoms for depression: