Everyone has days when things do not feel right and a mood strikes them. Some get over it rather well while others have it drag on for hours, days, or even weeks. Sometimes they seek help from a doctor and drugs are prescribed. They may help in the short-term but the problem remains. Sometimes it gets to be so bad that stronger drugs and other things are required. For some they may choose to end their lives.
As a spiritual person with a link to the Spirit of the Universe in my experience everyone has the same connection. We are puppets on strings in God's plan and we are pushed along to serve in ways we have never expected. Some break the string and become rebellious to it and they wander in disillusionment and depression as a result.
It's the disillusions that they generate or take part in that are the biggest causes of depression. They can be drugs; alcohol; acting; writing; and any form of fiction. They can also be the false gods of religions that people pray to without answers. To force them to continue to believe they are threatened with hell and that creates another form.
Without the spiritual connection we walk on paths that lead to a state of anxiety. We head into the wilderness of worldly lies and money. Peace escapes us and accidents, diseases, and loss beset us. This is what the community of manfinders prefers to the peaceful knowing and acceptance of the Great Spirit.
Heaven and hell are fake. They are the weapons of power and are used as whipping sticks to drive people into congregations and belief systems that is against their grain. That is especially true if they have a connection in place. They feel empty inside, even dark or black. They want to escape but the threat of eternal punishment is the guard on the door.
My reincarnation is proof that everyone has reincarnated, as told in the Old Testament (Job 5: 19-21 and Isaiah 26:19). In Job we are told we have reincarnated six times. Isaiah reminds us that at the end of days we will all be in our bodies for judgment.
Those who have broken the string are still used by God to complete the plan. The difference is they no longer hear the little voice within telling them what to do. Because they feel lost they have no comfort within themselves and they try desperately to 'fill the gap'. When they can not reconnect the body reacts and depression and mood swings set in. That is why the condition is a physical one and not a mental dysfunction. Drugs will not help it either.