Research shows that people with anxiety who do not take an antidepressant were more likely than healthy people to have higher diastolic blood pressure, although their risk is still lower than that of individuals who take tricyclics or SNRIs. Anxiety is likely to produce temporary spikes in blood pressure, rather than persistent hypertension, and research shows this to be the case.
But frequent spikes in blood pressure can still damage your blood vessels, heart, and kidneysas well as increase your risk of stroke.
Why It Happens
Researchers theorize that anxiety may increase blood pressure by causing the body to remain in a heightened state of stress. When we are in a "fight or flight" situation, heart rate and adrenaline levels increase to help us weather the crisis. Both of these responses can increase blood pressure.
This chain of events is not a problem when it happens occasionally. With chronic anxiety, however, the events happen too frequently, and blood pressure is elevated too often. The relationship among depression, antidepressants, and blood pressure is less well understood.
One theory is that low blood pressure often produces symptoms such as fatigue, dizziness, trouble concentrating, and feeling cold, which can in turn cause depression. Another theory is that both depression and low blood pressure have a common cause, such as a malfunction in metabolism that alters levels of hormones or neurotransmitters.
The association between hypertension and the use of tricyclic and SNRI antidepressants is likely related to the effect of these medications on the autonomic nervous system, which controls blood pressure.