Some theorists contend that depression is genetically based. Individuals who have depression are more likely than non-depressed individuals to have family members who have depression. It is not uncommon to see generations of family members suffering from depression.
Other theorists believe that depression may be environmental. In other words, we are often affected by the circumstances in which we are raised. If an individual experiences negative or difficult events throughout their life, such as having a family member (or several) commit suicide, these events may affect their state of mind or manner of thinking.
To answer your specific question, it’s best not to assume anything. Depression may be genetic but the fact remains that no one knows for certain exactly how or why people develop depression. I described two existing theories but there are many more.
It’s possible that you are experiencing depression because of the tragic loss of two immediate relatives to suicide. This is an extremely challenging set of circumstances. Almost anyone would struggle to deal with this immense loss.
How and why depression develops may not be as important as treating it. You mentioned that you’re taking antidepressants. It’s good to hear that you are engaged in some form of treatment. You should also consider talk therapy. It is important that you try to acquire as much support as possible during this time in your life. One place to search for support groups in your area can be found at the American Association of Suicidology. They have in-person groups around the country for family member survivors. I would highly recommend attending one of these groups, in addition to receiving grief counseling.
I’m sorry that you had to endure such difficult life circumstances. I hope you are able to access support. I wish you well. Thank you for writing.