The main reason is that people keep storing more and more subconscious imprints of pain, guilt, regret or uncertainty. The person may have been holding some painful memories of the past, or uncertainty of future. There may be a situation where the person thinks that the ongoing challenge of present is bigger than his resources.
This continuous negative engagement of the subconscious mind changes the whole patterns of the hormonal discharge also. The immune system is suppressed or confused because of this depression and the person is at the verge of various diseases like diabetes or even cancer.
Today what we need is to get rid of these negative subconscious imprints and install the delightful imprints in our subconscious mind. This where you need to learn subconscious re-imprinting.
There are a number of wonderful exercises of human wellness that can help you to not only delete the patterns of your depression but also enjoy the ultimate mental, emotional and physical wellness.
The first and foremost is 'Pacing Yourself'.
Pacing means to enter your own inner world. It is wonderful exercise to take your awareness to your inner world and learn as to what is going on inside you. It is like being an observer to your own world. To observe the sensations, vibrations, tensions, in your body and the images and audios in your mind. It is to find as to what your inner world wants to convey to you.
Once you do it, you start getting the hidden message that were going unanswered or unaddressed.
Once you start pacing yourself, you need to go ahead with various other subconscious exercises like Reframing or Anchoring with Submodalities.