In this first study, that compared four common classes of antihypertensive drugs and risk of mood disorders, two drugs were associated with an increased risk for mood disorders, while one appears to decrease mood disorder risk, according to the study author, and the work is published in Heart Association's journal Hypertension. 

Researchers collected data on 525,046 patients (ages 40-80) from two large secondary care Scottish hospitals. They selected 144,066 patients being treated for hypertension with either angiotensin antagonists, beta blocker, calcium channel blockers or thiazide diuretics.

They were compared to a group of 111,936 patients not taking any of those drugs. Researchers followed the patients for five years documenting hospitalization for mood disorders, such as depression or bipolar disorder. After more than 90 days on the antihypertensive medications, they found:

There were 299 hospital admissions, predominantly due to major depression, among the patients studied, at an average 2.3 years after patients began antihypertensive treatment.

Patients on beta-blockers and calcium antagonists were at two-fold increased risk of hospital admission for mood disorder, compared to patients on angiotensin antagonists (angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers).

Patients on angiotensin antagonists had the lowest risk for hospitalization with mood disorders compared to patients on other blood pressure meds and patients on no antihypertensive therapy.

Patients taking thiazide diuretics showed the same risk for mood disorders compared to patients taking no antihypertensive meds.

The presence of co-existing medical conditions increased the risk of mood disorders.

These findings suggest that angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers that are used to treat hypertension may be useful as new or "repurposed" treatments for mood disorders, according to the author.

"It is important that these results are validated in independent studies. This is a single center study, which looked at the risk of the more severe forms of mood disorders requiring hospitalization. It would be important to study the effect of these drugs on minor to modest changes in mood, as these will have an impact on the quality of life among hypertensive patients," author said.

http://hyper.ahajournals.org/content/68/5/1132