DSM-V includes megalomania as a psychological condition or narcissistic personality disorder symptom. It is associated with delusional ideas and fantasies of power or relevance.
They believe they’re the only person capable of doing things and won’t believe in anyone else.People with megalomania have an obsession with power and will do anything to gain it.
They have delusions of grandeur and can’t see their faults or shortcomings. Additionally, they don’t always realize that their view doesn’t correspond to reality.These people often use insults and narcissism to cover their subconscious fears.
Read more on powerofpositivity.com