OBJECTIVE: Neuroplasticity is a well-described phenomenon, but effects of non-pharmacological interventions on white matter (WM) are unclear. Here we review associations between active non-pharmacological interventions and WM organization in healthy subjects and in psychiatric patients.

METHOD: A systematic review of non-psychiatric and psychiatric studies in MEDLINE and EMBASE databases. We included longitudinal, controlled studies in human participants aged 18-60 years published in peer-reviewed journals between 2000 and 2017. Studies required active interventions lasting between one day and one year, targeting cognitive-, motor- or sensory domains. The primary outcome was intervention-related brain changes in diffusion-weighted imaging (DWI) derived measures.

RESULTS: We included 25 studies. Twenty studies reported positive findings. Five studies investigated psychiatric patients. Nine randomized, controlled trials (RCTs) reported DWI changes following cognitive interventions. Interventions were too heterogeneous to perform a meta-analysis. Intervention duration of at least eight weeks appeared required to induce consistent WM changes.

CONCLUSIONS: Non-pharmacological interventions can induce changes in WM. DWI is a relevant correlate of e.g. cognitive training in prospective, long-term RCTs of psychiatric patients.