For many reasons, self confidence can become grandiose and express as destructive narcissism.  All healthy people have good self esteem and a strong ego, critical components of surviving and thriving in a chaotic world.  The disordered personality is found more in males but is also found in females. Selfishness, arrogance, gaslighting, a lack of empathy and basic understanding of emotions are the hallmarks of this disorder, which has often been regarded as un-treatable. Sometimes difficult to spot when camouflaged by executive promotions and high political office, this personality disorder displays in alternating ways. The narcissist will at first fawn over or pay excessive compliments and attention to new acquaintances, then switch gradually to critical and controlling tactics that can often become emotionally and physically abusive.  Gaslighting becomes an early frequent symptom of this terrible burden on relationships.