A recent study published in the Journal of the American Medical Association concluded that depression is associated with a significantly increased risk of stroke morbidity and mortality. This means that if you have depression you are more likely to have a stroke and die from a stroke as compared to a situation where you didn’t have depression .
This is quite relevant to a large number of people since depression is quite prevalent in the general population. It is estimated that 5.8% of men and 9.5% of women will experience a depression e episode in a 12 month period. The lifetime incidence of depression has been estimated at more than 16% in the general population.
This research study was by Dr. An Pan and four colleagues from the Harvard School of Public Health and Harvard Medical School. The research was a meta-analysis and a systematic review which meant that the authors studied research of many studies on this subject The ended up looking at 28 prospective cohort studies comprising 317,540 participants which reported 8478 stroke cases during a follow-up period ranging from 2-29 years.
Their scientific analysis of the data demonstrated that depression is associated with a significantly increased risk of developing stroke. They also found a positive association of depression with a fatal stroke.
The authors discussed a variety of mechanisms which depression may contribute to stroke. Depression has known neuroendocrine effects. For example t there is a dysregulation of HPA axis ( hypothalamic-pituitary-adrencortical axis which can cause high blood pressure. It has been shown that depression effects platelets and leads to dysfunction which causes abnormalities in the clotting mechanism. There are also abnormalities in the immune and inflammation systems which could influence stroke risk..
Depression is associated with poor health behaviors such as smoking, physical inactivity, poor diet, lack of medication compliance and obesity, all of which may contribute to stroke.
Depression has already been associated with coronary heart disease, diabetes and hypertension. (See an earlier blog on depression and heart disease as well as another blog which raised the question whether people with depression should be taking aspirin to prevent heart attacks).
The data from the recent JAMA study also suggested that it is possible that antidepressant medication may be associated with stroke risk but this may be a false impression since medication use can be a marker of depression severity and many of the studies that the authors looked at lacked information on dose and duration of medication use.
There are some limitations of this study and the findings don’t prove 100% that depression causes stroke. I would imagine that it is conceivable that the genetic markers for stroke and depression could be located in close proximity leading to such impression of this effect. However even if there is no causative effect ( although I believe the research strongly suggest one ), the association of these conditions clearly calls out for great attention being paid to this association. There is an opportunity for doctors who see patients who are at a high risk for stroke to be referred for treatment of depression. Also patients who are being treated for depression should be encouraged to be seek medical attention and assistance in reducing all the other risk factors for stroke whenever possible.
Depression is a serious condition and is very treatable. Treatment works! Patients who have depression should be treated whether or not they are at a higher risk for stroke and other diseases.