🧠 Mental Health

Depression

• A 2022 meta-analysis of 20 clinical trials found that journaling and expressive writing reduced depressive symptoms by about 2–4 percentage points on average, with stronger effects in people experiencing mild or moderate depression.
• In a clinical study on major depressive disorder, just five days of expressive writing produced an average 35 % reduction in depressive symptoms, with improvements lasting at least four weeks.
• A large meta-analysis of 26 ,427 participants on gratitude journaling found a 34 % drop in reported depression and higher overall well-being compared to control groups.

Anxiety and Stress

• The same BMJ Open meta-analysis reported a 9 % average reduction in anxiety across expressive-writing trials.
• In a 30-day experiment with university students, daily expressive writing cut test anxiety by about 20 % relative to non-writers.
• A 12-week randomized online study in primary-care patients showed that positive-affect journaling led to 49 % lower anxiety scores and 35 % greater emotional resilience compared with usual care.
• Overall, around 85 % of participants across studies report that writing about difficult experiences helped them process emotions and feel calmer.

Post-Traumatic Stress & Rumination

• The BMJ Open review also found an average 6 % decrease in PTSD symptoms among expressive-writing participants.
• Expressive writing consistently reduces repetitive negative thinking: in one experiment it lowered rumination and intrusive thoughts by roughly 25 %, freeing up mental space for recovery (Gortner, Rude & Pennebaker 2006).

💪 Physical Health

Sleep

• Writing a quick bedtime to-do list for just five minutes helped participants fall asleep nine minutes faster than those who listed completed tasks (Scullin et al., 2018).
• In a series of gratitude-journaling studies, people who listed three good things each night reported better sleep quality, longer duration, and easier sleep onset. Follow-ups confirmed similar benefits in later research and replications.

Immune Function and Clinical Outcomes

• In a landmark JAMA trial, patients with asthma improved lung function from 64 % to 76 % of predicted capacity (≈ +12 points) after four expressive-writing sessions, while those with rheumatoid arthritis saw a 28 % reduction in pain and joint tenderness. Nearly half (47 %) of writers met the clinical-improvement threshold versus 24 % of controls.
• A study of HIV-positive patients found that those who completed four days of writing maintained higher CD4 immune-cell counts and a slower viral-load increase over six months.
• Comprehensive reviews, such as Baikie & Wilhelm (2005), summarize additional evidence for lower blood pressure, reduced stress-hormone levels, and improved recovery rates across multiple conditions.

⚙️ Cognition & Performance

Memory and Focus

• Across experiments, journaling improves memory recall by roughly 20–23 %, as writing enhances how the brain encodes new information (Klein & Boals 2001).
• 59 % of regular journalers say it helps them remember details better and think more clearly.
• Students in expressive-writing groups also reported 30 % fewer intrusive thoughts, freeing attention for learning and problem-solving.

Academic and Cognitive Performance

• A Science study found that anxious students who wrote for ten minutes before an exam improved their test scores by about six percentage points—nearly a full letter grade—compared to non-writers.
• University research at UC Berkeley similarly showed a 20 % boost in sustained attention among students who journaled regularly.

Work and Goal Achievement

• In a Harvard Business School field study, employees who spent 15 minutes journaling at the end of each day improved performance by 22.8 % during training, while peers who shared reflections saw 25 % gains.
• A Dominican University experiment found that people who wrote and reviewed their goals were 42 % more likely to achieve them than those who merely thought about them.

In Short

Consistent journaling—just 15 minutes a few times per week—has been shown to: