Answer:
Dissacoiative Identity Disorder is a highly stigmatized disorder that develops through immense tramua during your brains formative years (1-7ish). I believe in Dissociative Identity Disorder because of the amount of information and studies done on the disorder. There are hundreds of studies on this topic, including its own section in the Diagnostic and Statistical Manual of Mental Disorder (DSM) that highlights the issues and controversy behind it. The controversy behind it is mainly because of people not understanding fully how the brain splits personalities in development. Often times, only the highest of psycologists have run into this rare disorder during their practice.