Anxiety and depression are two separate conditions.
The exact relationship between the two is still under
study.

Even though it’s very common to find them together,
any direct relationship to each other has yet to be
found. For the time being, the relationship between
anxiety and depression is often referred to as
comorbidity.

Meaning unrelated but co-existing. Their symptoms can
overlap each other, which can make the initial
diagnosis of either condition difficult. The symptoms
can also be completely independent of each other.

A study by the National Comorbidity Survey reported
that 58% of patients suffering major depression also
exhibited lifetime anxiety. Agitated depression and
akathitic depression are most often referred to when
supporting these results.

Both of these depressed states exhibit anxiety with
heightened restlessness, suicidal thoughts or
tendencies and a general sense of dread. While
agitated depression includes symptoms of nonclinical
and nonspecific panic, akathitic depression doesn’t.

Even mild anxiety symptoms are being found to have an
impact on the course depression takes in individuals.

A study at the University of Pittsburg showed patients
diagnosed with depression and also suffering lifetime
panic symptoms experienced significant delays in the
success of their treatments.

These patients also exhibited additional problems when
facing the resumption of their normal activities.

There are theories regarding the possibility that
depression acts similar to anxiety in attempting to
encourage avoidance of potentially harmful situations.
Anxiety tries to avoid and prepare for physical
danger, while depression tries to avoid emotional or
psychological danger.