Study Contradicts Depression/Hypertension Theory

The study seems to contradict the theory that people with depression are more vulnerable to cardiovascular problems because their depression raises their risk for hypertension.

"We showed that depression itself was not associated with high blood pressure and hypertension, so the hypothesis does not seem to hold," said Licht, who is preparing her doctoral dissertation on the role of the autonomic nervous system in the relationship between depression (and anxiety) and cardiovascular diseases.

While the study found an association between low blood pressure and depression, it found a link between high blood pressure and anxiety.

Subjects for the study were part of the Netherlands Study of Depression and Anxiety, an ongoing analysis of 2981 adults aged 18 to 65 years. From this sample, 2618 subjects were included in the current study.

Participants were divided into 3 groups: a control group with no history of anxiety or depressive disorder (590); patients with a major depressive disorder (MDD) or an anxiety disorder who did not take antidepressants (1348); and patients with an MDD or an anxiety disorder who were on antidepressant medication. The researchers also differentiated between subjects with a remitted MDD or anxiety disorder and those with a current diagnosis.

In the group using antidepressants, researchers determined the number of patients taking the various drugs: 442 used selective serotonin-reuptake inhibitors (SSRIs); 67 used a TCA; and 135 used an antidepressant that works on noradrenergic and serotonergic (NS) systems.

To assess blood pressure, investigators averaged systolic blood pressure (SBP) and diastolic blood pressure (DBP) measurements taken twice during supine rest and adjusted these readings for use of hypertension medications.
They then created a 5-category hypertension indicator:

• No hypertension (63.7% of study sample).
• Isolated systolic hypertension (15.8%).
• Isolated diastolic hypertension (2.7%).
• Hypertension stage 1 (defined as SBP greater than or equal to 140 and DBP greater than or equal to 90) (13.1%).
• Hypertension stage 2 (SBP greater than or equal to 160 and DBP greater than or equal to 100) (4.7%).

There was no difference in use of antihypertensives between the 3 groups.

Investigators also measured heart rate and respiratory sinus arrhythmia (RSA) and collected information on body-mass index and other variables including age, sex, and education. Compared with controls, subjects with a psychiatric disorder were a little older, more likely to be female, less educated, less physically active, smoked more, and had a higher body-mass index and more diseases.

Compared with healthy controls, patients with an MDD had a significantly lower mean SBP (remitted diagnosis: P = 0.02; current diagnosis: P = 0.002) and were less likely to have isolated systolic hypertension. Both remitted and current MDD was associated with lower SBP even after researchers corrected for antidepressant use, RSA, and heart rate.

Patients taking a TCA had up to a 9% higher mean SBP and an 11% higher mean DBP compared with healthy controls and nonmedicated patients. And they had about double the risk of having hypertension stage 1 and almost triple the risk of having hypertension stage 2.

The association between raised blood pressure and NS-working antidepressants was similar but weaker than that between TCAs and increased blood pressure. The use of SSRIs was not significantly associated with increased blood pressure or hypertension.

Cell Metabolism, March 2009