Thalamocortical functional connectivity and cannabis use in men with childhood attention-deficithyperactivity disorder.
Disruptions of the cortico-striato-thalamo-cortical circuit has been implicated in both attention-deficithyperactivity disorder and substance use disorder. Given the high prevalence of cannabis use among patients with attention-deficithyperactivity disorder, we set out to investigate the relationship between the two in the thalamus. We analyzed resting-state functional magnetic resonance imaging data obtained from the Addiction Connectome Preprocessed Initiative Multimodal Treatment Study of Attention-DeficitHyperactivity Disorder database. Functional connectivity maps were extracted to compare thalamic connectivity among adults who had been diagnosed with attention-deficithyperactivity disorder during childhood according to whether or not they used cannabis. The study participants included 18 cannabis users and 15 cannabis non-users with childhood attention-deficithyperactivity disorder. Our results revealed that adults with attention-deficithyperactivity disorder who used cannabis (n 18) had significantly decreased functional connectivity between the thalamus and parietal regions, which was particularly prominent in the inferior parietal areas, in comparison with those who did not use cannabis (n 15). Left thalamic functional connectivity with the inferior parietal and middle frontal areas and right thalamic functional connectivity with the inferior parietal and superior frontal areas were increased in non-users of cannabis with attention-deficithyperactivity disorder compared with a local normative comparison group (n 7). In conclusion, adults with a childhood history of attention-deficithyperactivity disorder who do not use cannabis often have relatively stronger thalamoparietal and thalamofrontal connectivity, which may help reduce the risk of cannabis use.