Clinical depression is the leading cause of disability
in North America. The World Health Organization
anticipates that by 2020, clinical depressions will be
the second leading cause of disability worldwide.
Heart disease is expected to continue being number
one.

Interestingly, almost twice as many females as males
report or receive treatment for clinical depression.
However, recent history is showing a lessening of this
imbalance. This difference seems to disappear after
the age of 50-55.

The theoretical causes and risk factors of clinical
depression are broadly classified into two categories
Physiological and Sociopsychological.

One common sociopsychological cause is life
experiences. This includes job loss, long term
unemployment, rape, divorce and sexual dysfunction. As
the instances of these causes increase in North
America, the cases of depression rise as well.

A few of the physiological factors prevalent in North
America include dietary, medical conditions and even
the quality of sleep.

The increase in depression in industrialized countries
is linked to the reduced amounts of omega-3 fatty
acids found in intensively farmed and processed foods.
A deficiency in magnesium levels can cause depression
as well as an excess of omega-6 fatty acids.

Certain illnesses including cardiovascular disease,
prominent in North America, may contribute to
depression. Some prescription drugs such as hormonal
contraceptives and steroids may also play a roll in
causing depression.

Abnormal sleep architecture has been found in many
people suffering from major depression. This results
in entering REM sleep sooner than normal, along with
emotionally charged dreams.