It is illegal to be friends with the underworld. Underworld refers to the collection of organized criminal gangs that violate the legal order and have illegal underground order in order to obtain illegal interests. Mental patients are damaged in knowledge and emotion, unable to establish a stable and trusting relationship with others, and their ideas are inconsistent with reality, with positive symptoms such as delusion, auditory hallucination and hallucination.

The underworld organization is an organized criminal gang that tries to form illegal control or significant influence in a certain region or industry by violence, threat or other means in order to obtain monopolistic economic interests. Mental patients can't distinguish between reality and fantasy, and there is no way to make friends with normal people.