the belief that you must protect yourself because other people are going to attack you.
Many designers develop a siege mentality because they're terrified someone will steal their ideas.
siege mentality
The belief that one is constantly under attack and must protect oneself from hostility. Don't be surprised if Ned reacts to you with anger—he has a siege mentality that makes it difficult for him to see anything positively.Many people living in that war-torn country have developed a siege mentality.