The Role of the Supernatural in Character Development

There are some obvious similarities between The Amityville Horror (the 1979 film; I've never read the Jay Anson book) and The Shining (the 1980 film and, of course, the Stephen King novel). There is an evil house/hotel that terrorizes its inhabitants. Both stories also feature a lead male/father character who is extremely afflicted within the surroundings.

• George Lutz. James Brolin portrays this real person as a man who doesn't waste words. Gruff, with hints of a temper lurking close to the surface. He recently married Kathy, who has three kids from a prior relationship. The newly formed family is still getting used to life together.
• Jack Torrance. In comparison to the George Lutz film character, we're given much more insight (via the novel) into Jack and the personal history that led him to The Overlook. Alcoholism, rage, drunkenly breaking his son Danny's arm, hints at his misogynistic nature.

Family tensions fill these stories, before the horror starts

When these stories begin, everything isn't peaches and cream. The families grapple with various tensions before moving into the doomed house/hotel.

In Amityville, there are fragile relationships with stepkids; newlyweds who will have to scrimp and scrape to make mortgage payments. A man who likely led a rather solitary, independant life before marriage, suddenly thrust into the role of family man.

In The Shining, there's unemployment, writer's block. A recovering alcoholic with violent tendencies. A strained marriage, and worry about what's going on inside the son's head.

When the lead male character starts to act out, his behavior plays right into the wife's insecurities, anxieties, and fears about the relationship.

When the babysitter gets locked in the closet in Amityville, George and Kathy ask daughter Amy why she didn't open the door. Amy blames her unseen "friend" Jody. George bluntly tells Kathy that it's about time her kids had some damn discipline. The look on Kathy's face says it all. He just touched a nerve. She worries he will never accept her kids as his own, that he doesn't respect her as a mother, etc.

Later on, when Kathy tries to convince him to abandon the malevolent house, he says, "You're the one that wanted a house. This is it, so just shut up!" Another hint at the non-supernatural tensions that pulled at their lives before they moved into the house.

"I've  always been crazy,
but it's kept me from going insane"
- Waylon Jennings
Did the supernatural create his behavior,
or just push him over the edge?

How much influence does the supernatural have on George and Jack's misbehavior? Does the supernatural possess George/Jack, causing them to act negatively against their will? Or does the supernatural sense negativity within George/Jack, and use it to exploit their natural tendencies? Or do George/Jack sense a supernatural presence, then react to it in the same (albiet more extreme) way they would react to any other external stressor (work stress, family stress, etc.) - i.e. by lashing out?

According to Wikipedia,  Stephen King "viewed Jack as being victimized by the genuinely external supernatural forces haunting the hotel, whereas Kubrick's take viewed the haunting and its resulting malignancy as coming from within Jack himself."

Based on how these lead male characters operate in the beginning (before the horror starts) - and based on the backstories provided - the lead male's intense/undesirable actions (as a reaction to and/or result of supernatural forces) don't contradict the way they've been characterized.

Yes, the walls drip blood and there are bad vibes in Room 217. However, the most compelling aspect of these stories is the unraveling of the lead male and the family dynamic. The supernatural horror and male misbehavior is an external extension of darker impulses glimmering in the depths of the lead male characters - impulses that their wives had previously sensed, but believed/hoped would never surface.

Within the world of these stories, perhaps it is easier for the wives to accept their husbands' misbehavior once they begin to believe that their husbands are influenced by supernatural forces. What's scarier? A supernatural presence that can take over your mind and personality, or realizing that someone you love (and even yourself) has undesirable capacities?