The Words We Choose: James Pennebaker, the author of The Secret Life of Pronouns, has spent more than 30 years studying the psychological causes of physical illnesses. What he’s found is that the words we choose can affect our physical and mental health, and even alter our mood.

In one study Pennebaker found that writing 15 minutes a day can help fight cancer, high blood pressure, heart attacks and loneliness. It seems that writing may fulfill the same function of “unloading” as talking to another person. Subjects who wrote about emotionally significant events in their lives were able to function better than those that wrote about neutral objects. They visited the doctor less frequently, took fewer aspirins, got the flu less and generally felt better. Likewise, writers who varied the pronouns they were using laughed more than those who stuck with the singular form. In another study Pennebaker found that subjects who used more negative emotion words, such as “sad or “angry” were not generally helped by the writing exercise.

Journaling, or 15 minutes of daily “healthy writing,” has been shown to improve mood, aid in processing trauma or emotional events, and enhance performance throughout the day. It turns out that the words we choose to use in journals also show up in our conversations, and this can affect our relationships with others and how we perceive the world.