What is the worst sin a son could commit? Wouldn’t the worst thing be for a son to kill his mother? And wouldn’t having an affair with his brother’s wife be the worst thing a brother could do? These despicable acts are at the center of “Before the Devil Knows You’re Dead.” Before the story ends, the father of this disturbed family takes an unusual action to set the world straight again.

Charles Hanson (Albert Finney) and Nanette Hanson (Rosemary Harris) are good, hard-working parents who loved their children and gave them everything they needed. At yet, their sons, Andy Hanson (Philip Seymour Hoffman) and Hank Hanson (Ethan Hawk) have grown up into disturbed, immature, and dangerous men. Most of us have known others, or have experienced ourselves, some form of “affective” emotional disorder. Affective disorders include depression and mania or some combination at all levels of intensity. Affective disorders go up and down with a person (sometimes better, sometimes worse) and can usually be helped with medication and psychotherapy.

There is another category of emotional difficulty called “personality disorders.” Personality disorders represent a pervasive maladaptive way of dealing with people and the world. Personality disorders do not go up and down, are not helped by medication, are more debilitating to the individual, and make for a much more dangerous person in the family and in society. Each of the Hansons’ sons represents a classic personality disorder. Andy Hanson is a drug-addicted businessman who has embezzled thousands to support his habit and to pay for things in an effort to get his wife (Marisa Tomei) to shower him with adoration. The movie opens with Andy having sex with his wife, all the while watching his own performance in a mirror, which pretty much explains the depth of his person.

Hank Hanson is a child in a man’s body, a body that has produced a daughter that he is too undeveloped to take care of financially. If more evidence of Hank’s pervasive maladaptive way of dealing with people was necessary, the only thing Hank really cares about is his afternoon quickies with his brother’s wife. As their lives have played along, both brothers’ problems have narrowed down to money. If Hank doesn’t pay his back child support, he will lose the privilege of seeing his daughter. Andy’s embezzlement is on the verge of being revealed. Out of this desperation, Andy talks Hank into robbing their parents’ jewelry store. Hank, afraid of being recognized and swamped by other fears, brings in a third party at the last minute who shoots and kills Mrs. Hanson when the robbery goes bad.

Following up the botched robbery with more killing, Andy ends up in the hospital with a non-fatal gunshot wound and Hank hits the road. The hero emerges when the boys’ father makes a decision to try and undo what he’d created. He cuts off his son’s air supply long enough to kill Andy, then walks out of the hospital. The mystery here is how did these boys, whose parents seem so nice, turn out so badly? “Before the Devil Knows You’re Dead” doesn’t give us that answer, but leaves us with the more terrifying reality that no matter how hard parents try, some really bad people reach physical maturity and are turned out into the community.