A study was published in 2017, which investigated the effect that "positive writing" had on people with depressive symtoms. The people included in the study were recruited from german rehabilitation hospitals, and were ending their stay there.
Positive writing is a form of writing that is sometimes used for people with depressive symtoms, where the writer is asked to keep a journal where the focus is on reminding oneself and identifying key resources in life. PW is thus focused on two central parts. Reflecting on personal positive memories and values, and recognizing personal skills and resources.
170 patiens were randomly assigned to either keep a positive writing journal to write in for 3 days a week - 10-30 minutes a time. Or to just keep on as usual.
At the end of 4 weeks, the intervention group had significantly lower rates of depressive symtoms and also seemed better able to regulate their emotions adequately.
All in all - this study highlights the positive effect that can be gotten from concretely putting your focus on the resources you have around you. It seemed as if putting ones mental energy on potential rather than problem, could induce a positive and self-reinforcing upward spiral regarding mental health.
M, Suhr. A, K, Risch. G, Wilz. (2017). Maintaining mental health through positive writing: Effects of a resource diary on depression and emotion regulation. Journal of clinical psychology. 73(12). 1586 - 1598.