When you can’t forgive yourself, it’s easy to lose faith in a higher power. It happened to no less than former first lady Laura Bush.

In November 1963, two days after she turned 17, the then Laura Welch was driving on a highway on the outskirts of Midland, Texas. Unaware of a stop sign at an approaching intersection, she plowed into a car being driven by a good friend from high school, Mike Douglas. She was unhurt; Douglas was killed. She recalled the incident in her memoir, “Spoken from the Heart.”

After the crash, she remembers saying, "Please, God, please, God, you know, let him be OK," she told CNN’s Larry King in an interview last year. “And you know,” she told King, “it was like no one heard.” She lost her faith for many years.

“I dealt with it by trying not to think about it,” she said. “You just swallowed your troubles and went on.”

In his recent book, “Half a Life,” author Darin Strauss relates a similar incident – he ran into a cyclist, killing her, when he was 18 – and the difficulty he had in coming to terms with its enormity.

When I asked Strauss if he'd appealed to faith or a higher power when coping with the accident, he said he'd never considered it: he was raised in a secular household and thought himself "too meek to shake a fist at God."

But for those raised in a religious tradition, it's a logical step.

Indeed, one way of coping, says Gregory LaDue, a therapist and Methodist minister based in San Diego, is to get angry at God.

“The randomness of the world is there whether you believe in God or not,” he says. “But I’ve had people who come out of a faith tradition who got angry – really pissed – shook their fist at God and said, ‘F- you’ to God … and in that, found some sense of relief.”

But Dr. Gaby Cora, a Miami psychiatrist, says that religion can sometimes hinder forgiveness and letting go.

“There are some religions that have more of that guilt," she said. "In Catholicism, for example, you’ll see people feeling more responsible, and there’s a lot more of that inherent guilt going around – and you will not see that in Buddhism, for example.”

Nevertheless, forgiveness – of others, and ultimately, of yourself - is a big part of many faiths.

The New Testament repeatedly stresses the concept. “Bear with each other and forgive whatever grievances you may have against one another. Forgive as the Lord forgave you,” says Colossians 3:13. In Judaism, Yom Kippur – the Day of Atonement – requires that Jews ask for forgiveness from others who have been sinned against, and grant forgiveness to ourselves and those who ask it.

Anger and grudges should be discarded: "Thou shalt not hate thy brother in thy heart," says Leviticus 19:17-18. "… Thou shalt not take vengeance, nor bear any grudge against the children of thy people, but thou shalt love thy neighbor as thyself.”

“Ultimately, there’s a humbleness that comes when we realize that there’s something or someone out there bigger than myself that ultimately loves me, accepts...