Having suffered from clinical depression all my life, you'd think I'd have more answers by now. I am currently on meds and have tried nearly two dozen different meds and therapies. I've been in therapy and hospitalized for major depression. And still, the question I ask various doctors repeatedly is "Which came first, the chicken or the egg?" Is the depression the result of environmental issues (raised in an N family) followed by a number of negative life experiences? Or, did the negative life experiences come first followed by a major depression? The answer is invariably is "We don't know. It's likely a combination of both biological and situational factors."
After having studied depression and NPD extensively now, I do believe that the N situation either caused or greatly contributed to my lifelong depression. Some have told me my depression can be directly tied to my family situation. My recent doctor has suggested a I consider a surgical procedure in which a device would be implanted in my body to help regulate my depression and emotions.
And yes, I have also read often how some believe that depression is simply anger turned inward. Personally, I think that is too simplistic an explanation. It would follow then if you came to terms with that anger, identified it and expressed it, then the anger, and thus the depression, would disappear. But that is not the case. At least not with me.
The really terrible thing is while depression (in my case) may be a direct result of being raised in an N household and having an N family, it affects every aspect of my life. And of course, Ns have absolutely, positively no patience or empathy for those who suffer, particularly from an emotional disorder like depression. They view it as a sign of weakness. Ns want nothing to do with weakness. How ironic that the very symptoms of major depression (debilitating fatigue, sadness, lack of interest, lack of motivation) are those that the Ns just can't tolerate. It is one more thing that convinces the N you are a failure, unworthy and unvaluable. Nearly every doctor I have ever been so has says the opposite...i.e., that you have to be a very strong person to struggle through depression.
It has been my experience that no one tolerates very well someone with depression. They don't understand it and certainly don't want to be around it. They have absolutely no empathy for those suffering from it. The result is that the very thing you need as a depressive (support, encouragement, attention, empathy, compassion) are nowhere to be found.
I just can't help thinking how can you not be depressed after living a lifetime with serious Ns? You'd have to be superhuman not to have it affect you.