In 1986, James Pennebaker at the University of Texas in Austin turned his introductory psychology class into an experimental laboratory.

Pennebaker started with a healthy respect for keeping things to yourself, which he viewed as the glue of civilization.

But he also assumed that people pay a price for trying to suppress being aware of the elephant in the room.

He began by asking each student to identify a deeply personal experience that they’d found very stressful or traumatic.

He then divided the class into three groups: One would write about what was currently going on in their lives; the second would write about the details of the traumatic or stressful event; and the third would recount the facts of the experience, their feelings, and emotions about it, and what impact they thought this event had had on their lives.

All of the students wrote continuously for fifteen minutes on four consecutive days while sitting alone in a small cubicle in the psychology building.

The students took the study very seriously; many revealed secrets that they had never told anyone.

They often cried as they wrote, and many confided in the course assistants that they’d become preoccupied with these experiences.

Of the two hundred participants, sixty-five wrote about childhood trauma.

Although the death of a family member was the most frequent topic, 22 percent of the women and 10 percent of the men reported sexual trauma before the age of seventeen.

The researchers asked the students about their health and were surprised how often the students spontaneously reported histories of major and minor health problems: cancer, high blood pressure, ulcers, flu, headaches.

Those who reported a traumatic sexual experience in childhood had been hospitalized almost twice the rate of the others.

The team then compared the number of visits to the student health center participants had made during the month before the study to the number in the month following it.

The group that had written about both the facts and the emotions related to their trauma clearly benefited the most:

They had a 50 percent drop in doctor visits compared with the other two groups.

Writing about their deepest thoughts and feelings about traumas had improved their mood and resulted in a more optimistic attitude and better physical health.

When the students themselves were asked to assess the study, they focused on how it had increased their self-understanding:

“It helped me think about what I felt during those times. I never realized how it affected me before.”

“I had to think about and resolve past experiences. One result of the experiment was peace of mind. To have to write about emotions and feelings helped me understand how I felt and why.”

In a study that followed Pennebaker asked half of a group of seventy-two students to talk into a tape recorder about the most traumatic experience of their lives; the other half discussed their plans for the rest of the day.

As they spoke, researchers monitored their physiological reactions: blood pleasure, heart rate, muscle tension, and hand temperature.

This study had similar results: Those who allowed themselves to feel their emotions showed significant physiological changes, both immediate and long-term.

Under normal conditions, you react to a threat with a temporary increase in your stress hormones.

As soon as the threat is over, the hormones dissipate and your body returns to normal.

But if you choose to go on as if nothing has happened.

The emotional brain will keep working.

And stress hormones will keep sending signals to the muscles to tense for action or immobilize in collapse.

The physical effects on the organs will go on unabated until they demand notice when they are expressed as illness.

Medications, drugs, and alcohol can also temporarily dull or erase unbearable sensations and feelings.

But the body continues to keep the score.

The insidious effects of constantly elevated stress hormones include memory and attention problems, irritability, and sleep disorders.