Yeah I used to believe that but having but having lived through a lengthy episode of being in a somewhat depressed and fatigued state, and having researched and observed it in myself and others, I no longer buy that depression can &quot;happen completely independent of your life circumstances&quot;.<p>The main reason for this is that it&#x27;s fallacious to think that your emotions are &quot;completely independent of your life circumstances&quot;. They&#x27;re symbiotic.<p>I was born into modest privilege and had an upbringing that was free of abuse or major trauma, and the only things that have gone severely wrong for me in life have been through my own poor decisions.<p>Yet I can now easily see how the depression I&#x27;ve experienced was due to a <i>combination</i> of living in a somewhat unhealthy environment and having a propensity to respond to that environment by becoming depressed and fatigued. I can now see the same applies to everyone else I know of who experiences depression.<p>The explanation you&#x27;ve given is embraced by mental health professionals as it allows them to justify attempting to cure it with pharmaceuticals and short therapy consultations, but as the data shows, that approach has a pretty low success rate.