Now, in my 70s, I can look back and see the circuitous route my own faith has traveled. I consider it to be pretty adult, though, remarkably --- having lived through all sorts of triumphs and travails --- it doesn't seem that different in its simplicity and wholeness from the faith I recall having as a child.

I was brought up in a religious home and sent to religious schools. I attended Mass often. The idea that God might be a figment of human imagination or that Jesus might not really be present in the Eucharist never entered my mind.

When, in my education as a psychiatrist, I was being considered for a position as a psychiatric resident, the interviewer asked if I anticipated any serious conflicts between my faith and what I was going to see and experience as a doctor. "Of course not," I replied, quickly and quite naively.

I was a green recruit. My faith never had been tested in life's battlefields. But in subsequent years, it was to be challenged time and time again --- intellectually, in conversations with bright, thoughtful colleagues who were, at best, agnostic; clinically, in the suffering and despair of many patients; personally, in disappointments, tragedies and seemingly unanswered prayers; and by human flaws in organized religion.

For many friends, these realities proved to be too much. Disheartened and angry, they sought other outlets for spirituality or abandoned faith altogether. Luckily, or blessedly, my faith prevailed.

But it also changed. The pain of loss gave way to a stronger, deeper faith centered on prayer, the sacraments, ongoing reappraisal of my relationship with God and a new sense of comfort with my own being.

I don't doubt that this maturing manifested itself in the effectiveness of my work with patients. There was, for example, a 43-year-old woman who had been religious as a child but never had forgiven God for the loss of her father when she was 17, and there was the 57-year-old man who had not even prayed since age 11 when his pastor admonished him heatedly for being late for Mass.

In each case, a spiritual presence in their lives was restored in the process both of treating an underlying clinical depression that was compounding their absence of faith and of encouraging the patients to engage in the process of forgiveness.

As I see it, adult faith is learned and earned. You have to appreciate it, work on it, nurture it so that, in the end, it becomes the seasoned source of strength and security it is meant to be.

Frederich Flach, a psychiatrist in New York City, is a knight of the Equestrian Order of the Holy Sepulchre of Jerusalem.