Non-pharmacological modulation of cerebral white matter organization: A systematic review of non-psychiatric and psychiatric studies

•Non-pharmacological interventions can induce changes in white matter.•Minimal intervention duration of 8 weeks is required to induce consistent WM-changes.•Associations between cognitive interventions and WM is substantiated.•DWI is a relevant correlate of cognitive training in RCTs of psychiatric patients. 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. 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. 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. 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.