Transcranial magnetic stimulation and neuroimaging for cocaine use disorder: Review and future directions

Background: Cocaine use disorder (CUD) is a public health problem with limited treatment options and a significant relapse rate. Neuroimaging studies have identified abnormal functional connectivity in individuals with substance use disorders. Neuromodulation has been proposed to target this altered neurocircuitry. Combining TMS with neuroimaging has the potential to inform identification of biomarkers, diagnosis, and treatment.Objectives: We review the literature of transcranial magnetic stimulation (TMS) with neuroimaging for CUD and outline a research path forward whereby TMS can be used to identify brain network features as diagnostic or prognostic biomarkers for treatment.Methods: We reviewed the literature for primary research studies of TMS with neuroimaging for CUD. We searched PubMed using search terms of "cocaine," "transcranial magnetic stimulation," and "neuroimaging." Identified studies were screened by title and abstract. Full-text studies were reviewed for inclusion.Results: In our initial search, we identified 73 studies. Six studies met our inclusion criteria. These studies used rTMS (n = 3) and single or paired pulse TMS (n = 3) and included a total of 289 participants. All studies used fMRI as the neuroimaging modality. The most common outcome measure was craving and cue-reactivity (n = 3).Conclusion: The literature combining TMS with neuroimaging is small and heterogeneous. We propose that combining TMS with neuroimaging will accelerate our understanding of substance use disorder neurobiology and treatment. Once network biomarkers of substance use have been identified, TMS can be used to manipulate the dysfunctional circuits in order to identify a causal relationship between connectivity and psychopathology.