Preclinical studies suggest that cannabidiol (CBD), a non-intoxicating phytocannabinoid, may reduce addiction-related behaviours for various drug classes in rodents, including ethanol, opiates, and psychostimulants. CBD modulates contextual memories and responses to reward stimuli. Nonetheless, research on the impact of CBD on cocaine addiction-like behaviors is limited and requires further clarification. This study tested the hypothesis that CBD administration inhibits the acquisition and retrieval of cocaine-induced conditioned place preference (CPP) in adult male and female C57BL6/J mice. We also ought to characterise a 5-day CPP protocol in these animals.

Male and female C57BL/6J mice were administered CBD (3, 10, and 30 mg/kg) 30 minutes before cocaine (15 mg/kg) acquisition of expression of CPP.

Cocaine induces a CPP in both female and male mice in the 5-day CPP protocol. CBD failed to prevent the acquisition or retrieval of place preference induced by cocaine. CBD did not decrease the time spent on the side paired with cocaine at any of the doses tested in male and female mice, in either acquisition or expression of contextual memory.

This study found no support for the hypothesis that CBD decreases reward memory involved in the formation of cocaine addiction. Further research is necessary to investigate the involvement of CBD in other behavioural responses to cocaine and other psychostimulant drugs. This study, however, characterised a 5-day CPP protocol for both female and male C57BL/6J mice.

While the neuroanatomic substrates of symptoms of attention deficit hyperactivity disorder (ADHD) have been investigated, less is known about the neuroanatomic correlates of cognitive abilities pertinent to the disorder, particularly in adults. Here we define the neuroanatomic correlates of key cognitive abilities and determine if there are associations with histories of psychostimulant medication.

We acquired neuroanatomic magnetic resonance imaging data from 264 members of 60 families (mean age 29.5; s.d. 18.4, 116 with ADHD). Using linear mixed model regression, we tested for associations between cognitive abilities (working memory, information processing, intelligence, and attention), symptoms and both cortical and subcortical volumes.

Symptom severity was associated with spatial working memory (t = −3.77, p = 0.0002), processing speed (t = −2.95, p = 0.004) and a measure of impulsive responding (t = 2.19, p = 0.03); these associations did not vary with age (all p > 0.1). Neuroanatomic associations of cognition varied by task but centered on prefrontal, lateral parietal and temporal cortical regions, the thalamus and putamen. The neuroanatomic correlates of ADHD symptoms overlapped significantly with those of working memory (Dice's overlap coefficient: spatial, p = 0.003; verbal, p = 0.001) and information processing (p = 0.02). Psychostimulant medication history was associated with neither cognitive skills nor with a brain–cognition relationships.

Diagnostic differences in the cognitive profile of ADHD does not vary significantly with age; nor were cognitive differences associated with psychostimulant medication history. The neuroanatomic substrates of working memory and information overlapped with those for symptoms within these extended families, consistent with a pathophysiological role for these cognitive skills in familial ADHD.