Most of the cases if we have a mental disorder or dark and heavy feelings, these are influenced by the evil spirits attracted by your negative thoughts called 六大煩悩 (rokudai bonnou) “The Six Primary Delusions” in Buddhism. They are Greed, Anger, Foolishness, Doubt, Proud, Evil Views. Most influential ones are called also 心の三毒 (kokoro no sandoku) “Three Poisons of Mind”, such as greed, anger, foolishness. Including these elements, it is often said that we have hundred eight ”worldly desires” (煩悩) in Buddhism. Actually, 子煩悩 (kobonou) “Too much affection to your children” is one of them.
If you have greed, anger, or foolishness which is often appeared as your complaints, these negative thoughts invite evil spirits. It is often seen like this: if you want to be understood by someone, but he or she didn’t, then you make angry to him or her also complain. In this case if you cannot refresh your mind, darkness occupies in your heart. This negative darkness attracts evil spirits.
There is a law called 波長同通の法則 “The law that same wavelength attracts someone – like attracts like”. Your negative thoughts attract evil spirits possessing negativeness.
There are couple of ways to cease this situation. The most powerful one is to practice 反省 (hansei) “reflection” that has a physical force to get rid of evil spirits. It can be practiced just sit and relax for a while, then remember the situation that you caused darkness in your mind, reflecting one by one, correct its wrong thought and deed if you found and decide not to do it again. Rather than this simple prictice there is a sysmatic way to correct your thoughts and deeds such as “The Eightfold Path” looking yourself through eight steps for harmonizing your mind and heart. Let me talk about it some other time.