Open-label Feasibility Trial of HD-tDCS During Cognitive Behavioral Therapy for Cocaine Use Disorder

Overview

Cocaine Use Disorder (CocUD) is a significant public health issue with increasing cocaine-related overdose mortality. Effective treatments for CocUD are highly needed. One understudied target for CocUD therapeutics is improving cognitive function (CF) in that key theories attribute development of CocUD and other substance use disorders (SUD) to impaired CF, such as decreased ability to inhibit behavior. Heavy cocaine users show impairments in attention, working memory, planning, and response inhibition, affecting as many as 30-80% of individuals with SUD. These cognitive deficits affect patient engagement and participation in SUD treatment, thus necessitating SUD programs assess and accommodate cognitive problems throughout treatment.

Among persons with SUD, those with low CF show more attentional bias toward reward-associated cues, where relapse may stem from reward circuit activation by drug cues that is insufficiently checked by the neurocircuitry of the dorsolateral prefrontal cortex (DLPFC) thought to regulate behavior. Many skills for SUD recovery taught in cognitive behavioral therapy (CBT) are reliant on DLPFC directed top-down regulation, such as recognizing environmental triggers and recalling more healthy coping strategies. However, a challenge for CBT is poor encoding, retention and in situ invocation of these skills. Of interest is improving brain function in these individuals to assist in CBT effectiveness. One option is to use stimulants which have been shown to reduce cocaine use, but they have abuse potential. It is thus critical to discover safer neurobiological interventions that could improve CBT success without risking problematic interactions with commonly prescribed psychotropic medications. A promising neurobiological intervention for CocUD is transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique that induces changes in neuronal excitability via hypo- or hyper-polarization of underlying resting membrane potentials, resulting in lasting changes in network connectivity that extend beyond the stimulated brain region. When applied over DLPFC, tDCS has been shown to increase memory recall and other CF in older adults with mild cognitive impairment. In SUD, tDCS has also reduced stimulant craving compared to sham stimulation and to reduce rates of relapse in crack cocaine users. In persons with methamphetamine use disorder, tDCS over DLPFC reduced cue-induced drug craving, and this reduction correlated with tDCS-reinforced functional connectivity in the executive control brain network. Thus, tDCS may improve CBT encoding and adherence without potential side effects and abuse potential of medications.