A central question that has been argued over for years in the anxiety - depression field is, are anxiety and depression linked and importantly does can anxiety lead to depression?
A study published in the journal Psychological Medicine recently helps to answer this issue. The research by scientists at the Departments of Psychiatry and Preventive Medicine, Rush University Medical Center, Chicago conducted a long term (12 years) analysis of the metal health of 425 women (278 Caucasian and 147 African American) women in america. The women were measured annually for symptoms of anxiety and depression to see if where any depression manifested itself, anxiety tended to be a precursor to the depression.
Firstly they found that women with anxiety were more likely to suffer from a major depressive disorder than those who did not suffer from anxiety in the first place. In fact they discovered that if you suffer from anxiety for a year you are almost 50% more likely to suffer from depression than people without anxiety. If you have already suffered from a bout of depression you are even more likely to suffer a recurring episode of depression.
The researchers recommend people with anxiety are closely monitored for signs of the onset of depression during the year. Obviously it would be better to treat the anxiety and reduce the chance of depression significantly.
Kravitz HM, Schott LL, Joffe H, Cyranowski JM, Bromberger JT (2014) Do anxiety symptoms predict major depressive disorder in midlife women? The Study of Women's Health Across the Nation (SWAN) Mental Health Study (MHS). Psychological Medicine [2014:1-10] DOI: 10.1017/S0033291714000075