Six Weeks, Smartphones, and Lower Neuroticism

Many adults want to feel less neurotic, especially when worry, tension, or quick emotional swings get in the way. The study looked at a nonclinical route for change, because evidence about smartphone help and the steps that drive change is still thin. A group of 446 German-speaking adults took part. They were randomly assigned to different intervention groups for six weeks. The app-based program used theory-based strategies aimed at changing neuroticism at different levels.

Across the groups, people reported lower neuroticism right after the program. The self-report effect sizes were between d = -0.22 and d = -0.37. Those self-reported changes did not vanish quickly. They were still visible two months later, with follow-up effects around d = -0.16 to d = -0.33. Peer reports also showed an effect at follow-up for one of the two peer-report measures, with d = -0.18 to d = -0.30.

Comparing the groups showed an important timing pattern. Strategies aimed at momentary, state-level experiences produced bigger drops at first, but they faded sooner. Strategies aimed at habits had smaller early reductions, yet their benefits grew as time passed. That difference matters because it suggests that faster relief and longer-term change may need different design choices.

The strongest results came from behavior-focused strategies, especially when they were used for habits. These strategies worked well across self-reports and peer reports, both on their own and when added to other approaches. The findings show that neuroticism can shift within six weeks, and they also help separate which kinds of change mechanisms may be doing the work.