What would be a good reason for someone to commit patricide? In my story, someone does this, but I don't know why. All I know is that he does do it. His father was the Prime Minister, and he killed him, but I don't know why. What would be some good reasons?
There are many reasons, someone in public office will have a private life, maybe it was something in that life that he was murdered over. Patricide is just another name, reasons rarely change.
If he's the Prime Minister, was it some political reason? Did he do something unforgivably bad with politics? Is the son trying to replace him? Or pave the way for a friend/lover to run against the PM's replacement when he knew they'd never beat his father in a fair election? Although... it would probably be easier to sabotage that in a way that didn't involve murder. Otherwise, aside from all the Freudian stuff, find some personal reason? Is the guy a jerk to his family? Violent and dangerous away from the media's eyes? But really, it's your story... You should know the circumstances and stuff... Unless your story at the moment pretty much consists of "there's this guy who kills his dad who's the Prime Minister", in which case I think you need to do a lot more background work yourself before asking.
Maybe it was unintentional. A case of domestic violence by one on the other that resulted in the father dying. "I'm NOT going to let you ruin your life." Grabs arm. Scuffle ensues. Father ends up dead. -Frank
Childhood abuse could be a reason. If the child grew up battered or sexually abused, he or she might decide to take revenge. Or the child could have a drug habit or a gambling problem that the father finds out about. The child might kill the father rather than deal with the problem or have it publically exposed. You could have a bad seed child, a psychotic child with no conscience. Although I prefer characters who aren't so black and white, there are many literary examples of bad seeds with no particular justification for their evil.
Too many variables and unanswered elements in the question. the relationship has to establish the element that drives the child to kill a father. Others have mentioned those things. I agree that those are supporting reasons. However, people who have been though similar situations (in real life) may not have been driven to kill. What make one person kill in the same situation where another would not? Is the child devoid of the morality to not kill? Is the child troubled enough to know it's wrong but sees no other way out? Is the killing, though painful, to the greater good of society. A reason itself may not differentiate itself enough for the child to act and kill. What piece of the puzzle make this instance different where killing is the best or, for the character, the appropriate option. It not just something as abuse itself that make a killer but other circumstances that bring a person to kill. There's more context. If you take a reason from the Rolodex, it will read very flat. You must create the whole set of circumstances and ensure that it supports your story or it will seem like a cheap mechanism.
Ah Yes, I remember the last words my father ever said to me, just before he died. He said "NO SON! THAT GUN IS LOADED!" Top 10 reasons to kill pop? 10. Rite of passage (Young eat the old) 09. Evil (Just because I never liked him much) 08. Covering your tracks (Dad discovers your evil plans and is going to turn you in) 07. Turns out he's not really dad (He's some sicko scientist raising you as an experiment) 06. Sibling Rivalry (Pop loved big brother more than me) 05. Fed up (Dad just wouldn't shut up about the time I broke his golf trophy, even though I was just 3 years old at the time) 04. Inheritance (I want my money now) 03. Childhood Abuse/Neglect (Payback is a real stinker) 02. Revenge (Despised the way you treated mom all those years) And the number one reason to kill dad? 01. Can't wait to assume the throne (I wanna be King NOW!)
* He didn't know who his real father was (e.g, he was adopted). * He didn't know who it was he murdered (e.g, he was tricked, or killed someone from behind in a dark alley).