The Science of Journaling: What 146 Studies Actually Show

Writing your thoughts down feels as if it should help. Forty years of research says it does, a little, and it's fairly specific about which kinds of writing help and how often you need to do it.

Where the research started

In 1986, the psychologists James Pennebaker and Sandra Beall ran a small experiment with 46 university students (Pennebaker & Beall, Journal of Abnormal Psychology, 1986). On four evenings in a row, each student wrote for 15 minutes, either about a trivial assigned topic or about an upsetting experience from their own life. The students who wrote about both the facts of the event and their feelings about it made fewer visits to the health centre over the next six months. Straight after writing, though, their blood pressure was higher and their mood was worse. The authors called the findings preliminary.

That study started a long line of research. Pennebaker and many others repeated the experiment with different groups and outcomes, and within twenty years there were enough randomized studies to pool.

What the full evidence shows

In 2006, Joanne Frattaroli pooled 146 randomized studies of this kind of writing, which researchers call expressive writing or experimental disclosure (Frattaroli, Psychological Bulletin, 2006). The average effect was small but statistically reliable: r = .075, roughly a Cohen's d of 0.15.

It's worth being honest about how small that is. Journaling won't stand in for therapy or medication. Still, writing is free and takes 15 minutes, so a consistent positive effect across that many trials is worth knowing about. Writing about hard things can also feel worse at first, as it did for the 1986 students.

A small 2018 trial tried a different kind of writing (Smyth et al., JMIR Mental Health, 2018). Seventy medical patients with raised anxiety were randomly assigned to usual care or to an online positive-affect journaling programme: 15 minutes, three days a week, for 12 weeks, writing about good experiences and feelings. The journaling group reported less distress than at the start. Compared with usual care, they had fewer depressive symptoms and less anxiety after the first month, and more resilience after the first and second months. The authors described it as a preliminary trial.

Why putting feelings into words may help

One clue comes from brain imaging. In a 2007 study (Lieberman et al., Psychological Science, 2007), people who named the emotion in a distressing picture, which psychologists call affect labelling, showed a weaker response in the amygdala and other emotional brain areas than when they processed the picture in other ways. That study was about labelling pictures in a brain scanner, not about journaling, so it suggests a possible mechanism rather than proving one.

If you want to try it, a minute of slow breathing first, such as the physiological sigh, can make it easier to sit down and start.

How often do you need to journal?

Less often than most apps suggest. The classic method is 15 to 20 minutes on three or four occasions, and the 2018 trial used three sessions a week. No study in this research shows that you need to write every day.

Some journaling apps lean on daily streaks and "you haven't written in 3 days" reminders. Those habits come from app design. If writing starts to feel like an obligation, it's fine to write only when something is on your mind. The Reflect team explains why their journal has no streak counter.

Which kinds of journaling have the most evidence?

• Expressive writing is Pennebaker's method: writing about your deepest thoughts and feelings about something stressful. It is the most studied.
• Positive-affect journaling means writing about good experiences and feelings. The 2018 trial used it and found modest gains in distress and resilience.
• Gratitude lists come from Emmons and McCullough's 2003 studies (Journal of Personality and Social Psychology, 2003). People who listed things they were grateful for, weekly in one study and daily in another, reported higher wellbeing on several measures. In a third study of adults with neuromuscular disease, the gratitude group also reported more sleep and better sleep quality.

In the 1986 study, the students who wrote about trivial topics didn't get the health-centre benefit. The benefit seems to come from writing about what happened and how you felt about it.

When to write, and when to get more support

The research points to a simple approach: write when something is weighing on you, give it 15 to 20 minutes, and include what you feel as well as what happened.

If you're writing about the same thing again and again, or it feels too big to carry alone, that's a good time to talk to someone. Therapy vs self-help looks at where each one fits. If the same worries loop every night, therapy for overthinking explains how that work goes, and emotional regulation therapy covers what helps when feelings swing hard and fast.

Frequently Asked Questions

Does journaling help with anxiety?

Modestly. A small, preliminary 12-week trial (Smyth et al., 2018, JMIR Mental Health) found that online positive-affect journaling went with lower distress in anxious medical patients, and less anxiety than usual care after the first month. Across expressive-writing studies, effects are small and results vary.

How long does journaling take to work?

The classic studies found benefits from 15 to 20 minutes of writing on three or four occasions. Across all the expressive-writing studies, the average effect is small.

Do you have to journal every day for it to work?

No. The classic expressive-writing studies used three or four sessions, and a 2018 trial used three a week. No study shows that you need to write daily.

What should you write about to get mental health benefits?

Pennebaker's research found the benefit came from writing about a stressful experience, covering both what happened and how you felt about it. Students who wrote about trivial topics didn't get it. Writing about good moments (positive-affect journaling) also has some trial support.

Sources

• Pennebaker JW, Beall SK. Confronting a traumatic event: toward an understanding of inhibition and disease. Journal of Abnormal Psychology. 1986;95(3):274-281.
• Frattaroli J. Experimental disclosure and its moderators: a meta-analysis. Psychological Bulletin. 2006;132(6):823-865.
• Smyth JM, Johnson JA, Auer BJ, et al. Online positive affect journaling in the improvement of mental distress and well-being in general medical patients with elevated anxiety symptoms: a preliminary randomized controlled trial. JMIR Mental Health. 2018;5(4):e11290.
• Lieberman MD, Eisenberger NI, Crockett MJ, et al. Putting feelings into words. Psychological Science. 2007;18(5):421-428.
• Emmons RA, McCullough ME. Counting blessings versus burdens: an experimental investigation of gratitude and subjective well-being in daily life. Journal of Personality and Social Psychology. 2003;84(2):377-389.