That and even something like Vestibular Disorders can cause depression. I'm not diagnosed with Clinical Depression but rather G.A.D. and with that comes some depression. Origin of the G.A.D. was finally traced down to Sensory Processing Damage namely the Inner Ear. But even a UTI can make someone borderline Clinical Depression highly depressed. All too often such things get overlooked.
As for spirituality, well....it was the opposite with me. The more I prayed, the worse it got. Oh well, live and learn.
Our Spirit whether we are aware or not in our time of need prays for us. Even a moan or a groan can be such. My problem with prayer myself is concentration. I have none. Mid-way through a short prayer my mind is gone elsewhere. That's typical with Vestibular patients.
Mine was ADD and a newbie thing called DESNOS; both have depression as components.
And yeah, I have the attention span of a gnat.