Effects of methylphenidate on resting-state functional connectivity of the mesocorticolimbic dopamine pathways in cocaine addiction

IMPORTANCE Cocaine addiction is associated with altered resting-state functional connectivity among regions of the mesocorticolimbic dopamine pathways. Methylphenidate hydrochloride, an indirect dopamine agonist, normalizes task-related regional brain activity and associated behavior in cocaine users; however, the neural systems-level effects of methylphenidate in this population have not yet been described. OBJECTIVE To use resting-state functional magnetic resonance imaging to examine changes in mesocorticolimbic connectivity with methylphenidate and how connectivity of affected pathways relates to severity of cocaine addiction. DESIGN Randomized, placebo-controlled, before-after, crossover study. SETTING Clinical research center. PARTICIPANTS Eighteen nonabstaining individuals with cocaine use disorders. INTERVENTIONS Single doses of oralmethylphenidate (20mg) or placebo were administered at each of 2 study sessions. At each session, resting scans were acquired twice: immediately after drug administration (before the onset of effects [baseline]) and 120 minutes later (within the window of peak effects). MAIN OUTCOMES AND MEASURES Functional connectivity strengthwas evaluated using a seed voxel correlation approach. Changes in this measure were examined to characterize the neural systems-level effects of methylphenidate; severity of cocaine addiction was assessed by interview and questionnaire. RESULTS Short-term methylphenidate administration reduced an abnormally strong connectivity of the ventral striatum with the dorsal striatum (putamen/globus pallidus), and lower connectivity between these regions during placebo administration uniquely correlated with less severe addiction. In contrast, methylphenidate strengthened several corticolimbic and corticocortical connections. CONCLUSIONS AND RELEVANCE These findings help elucidate the neural systems-level effects of methylphenidate and suggest that short-term methylphenidate can, at least transiently, remodel abnormal circuitry relevant to the pathophysiologic characteristics of cocaine addiction. In particular, the effects of methylphenidate within striatal and cortical pathways constitute a potentially viable mechanism by which methylphenidate could facilitate control of behavior in cocaine addiction.