Depression is a State where you have consumed a lot of energy for a very long time. It makes you run out, or have had a burn-out. In any case you arrived at the end of your abilities. Everything is black around you. Life has become colorless and you see no way out. You can go to the doctor, the psychologist or psychiatrist in the hope they have a cure.
That you have used a lot of energy is because you have no knowledge of dealing with your emotions. For too long have you been ignorant how you should deal with some or all of the emotions. Wrongly dealing with emotions means that you hold on to the emotion. It means that you are not or hardly talking about, for example, you do not shout while driving the car on the highway, you do not hit the table with your fist, you do not Ram the door, you do not let go of your tears, you do not roar with laughter, you do not express your romantic feelings or shout it from the rooftops, you do not allow you to let go sexually.
An emotion is a signal of your body what you must experience physically. It says attention! So feel the pain or grief, feel the joy or romantic love. Realize that you have an emotion: “I have an emotion”. Feel where in the body the emotion hits you. Then you can get to action or an act. By experienced it there it can no longer nestle itself and you can just let go of this emotion.
As soon as make a mental story of it for example by repeatedly talking about it, your basic needs are no longer met. Because you have parked (nestled) your emotions, they embed themselves in your body and mind. You become carried away by your emotions. Your energy systems (chakras and yin organs) become blocked. Within several months or years you have will hit a heavy depression.
The deeper cause of depression is not knowing how to deal with your emotions. Sometimes there is also talk of an intoxication (environment, food, medication, vaccination, pathogens),
When handling emotions well, order your consciousness, balance your consciousness (meditation, Self-Realization) with your beliefs you can better handle your emotions, it makes you stronger and resilient to intoxicating factors.
So help yourself and your descendants to handle with emotions.