A giant speculation in the Harry Potter fandom is whether or not Voldemort is a good guy or bad guy. Maybe he is terribly misunderstood. Maybe he is just the personification of evil. Maybe, just maybe, he likes being the bad guy. All of his tendencies and an explanation for why he is the way he is can be summarized by a little psychology.
Voldemort, formally known as Tom Marvolo Riddle, is a half-blood. His mother was a witch but sadly died after childbirth. His father, who was a Muggle, abandoned him shortly after his mother’s death, leaving him to be raised in a Muggle orphanage. Given this, he could have possibly suffered from Abandoned Child Syndrome and held on to the pain that comes with losing one’s parents. He never felt love and was never nurtured, so he felt alienated and distant from others. Ironically, love would be his downfall and would save Harry from his clutches.
Another possibility could be Irritable Male Syndrome, or a state of anger, frustration, anxiety and depression caused by chemical imbalances, loss of identity or stress. Voldemort was definitely imbalanced and possibly suffered from a lack of identity because he wasn’t happy just being Tom.
He could have been a Delusional Schizophrenic, more specifically grandiose. This is a person who has an over-inflated sense of worth, power, knowledge or identity. A person who possesses this believes that they have a great talent or made an important discovery. One sign given by Voldemort is when he discovers dark magic and the possibility of Horcruxes.
PTSD is also an option. With a constant reminder that he will never be loved and the fact that love was the reasoning for his demise, he constantly suffered from the memory of a poor childhood. He was never loved by his mother and hated by his father. Being bullied for being different in the orphanage could also have contributed to his PTSD.
These conditions could all explain why Voldemort is the way he is. He never chose to be evil, he was born into it. He never felt love or compassion, so hatred was all he knew. His overwhelming jealously of Harry and the fact that love protected him was constantly a reminder. Forming bonds with others did not come naturally to him, and his followers only followed him out of fear. At the end of the day, he only had himself (and his pet snake). His situations made him into who he is, so is he evil or did he just happen to have an unfortunate life that scarred him to the point of insanity?
