Every life has at least one crisis -- an avalanche that reshapes its emotional landscape. For Hector Aristiz?bal, this cataclysm came in 1982. At the time, Aristiz?bal was a passionate student at Universidad de Antioquia in Medell?n, Colombia, consumed by the innocuous diversions and immersions of a collegian: He was working toward a psychology degree, studying theater, and frequently marching for political causes.

In Colombia, though, behaving like a 'typical' student is perilous. This is a country where the days are often punctuated by gunfire; where over the past four decades billions in U.S. aid and countless acres of coca plants have funded a well-armed, violent conflict among guerrilla factions, drug cartels, and U.S.-backed shock troops. Violence, paranoia, and fear are, by design, daily companions for everyone. 'In my community of intellectuals and my family, we knew that when you dissent, the police can capture you and disappear you and torture you,' Aristiz?bal says.

A zealous priest, suspicious of the family's progressive politics, tipped off the army. Soldiers raided their home and found literature that landed Aristiz?bal and his brother in jail. After the arrest, Aristiz?bal spent three days and three nights in a torture chamber. Members of the Colombian army beat him and held his head underwater until he was on the brink of passing out. They applied electric shocks to his genitals. Hog-tied him and hung him from a pole. They also subjected him to sadistic mind games, including a mock execution.

Like most acts of war, torture is not random. 'Torture is a political tool, and its effects are intentional,' explains clinical psychologist Andrea Northwood, acting director of client services at the Center for Victims of Torture in Minneapolis. 'There's a general psychology to torture wherever it is practiced. It's designed to destroy the person's sense of integrity and identity.'

Torture manipulates the mechanisms in the brain and body in a way that results in trauma. And while it is an extreme act, unthinkable to most of us, the physiological effects can be virtually identical in people who face less dramatic situations. Even witnessing something ugly or frightening can trigger the same physical mechanisms. In fact, while the word trauma (or traumatic) is often used to describe an event like a car crash or a beating, psychiatrists and social scientists use the term to describe what takes place inside after these moments pass -- a physically taxing, soul-wrenching process. Most of us seek to avoid this sort of pain at all costs, but if we learn how to live with and learn from trauma, there's a good chance that in the process we will better understand both what it is to be human and how to gain access to our best selves.