Cannabis use is a growing health concern emphasizing the need to better understand the complexities of drug choice in people with daily/near daily cannabis use. Hypothetical purchasing tasks provide a means to collect data on drug consumption behavior without requiring drug administration and have been used to isolate behavioral economic factors of choice, including facets of drug demand in substance using populations. Various models are used for analyzing hypothetical purchasing task data, but challenges exist in modeling data sets with consumption values of zero. Additionally, a single model or approach may not be best for all commodities and drug classes. This study compared two common demand models (exponential vs. exponentiated) applied to identical hypothetical purchasing task data from 21 (n = 21) individuals with daily/near daily cannabis use. The exponential model was fit using three common levels of replacement values for zero consumption (.1, .01, .001) and compared to the exponentiated model without replacement values. We found that the exponentiated model produced significantly better model fits for individual data, compared to all exponential models. Additionally, significant differences for model derived values of demand elasticity and intensity were found between the exponentiated model and different levels of the exponential model. We conclude that the exponentiated model is preferred over the exponential model for performing demand analysis on hypothetical purchasing task data from individuals with daily/near daily cannabis use. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Recent advances in diagnostic research identified that individuals with higher impulsivity and sensation-seeking scores tend to report more positive subjective responses to stimulant drugs such as amphetamine. The current exploratory study hypothesized that differences in underlying mesocorticolimbic circuitry may mediate the relationship between personality and responses to stimulants due to its previously established implication in reward processes as well as the overlap between its dopaminergic projections and the pharmacodynamics of many stimulants. Forty participants (20 female) were recruited with relatively high- and low-impulsivity and sensation-seeking scores as defined by the Zuckerman-Kuhlman Personality Questionnaire (Form IIIR; Zuckerman, Kuhlman, Joireman, Teta, & Kraft, 1993) for a double-blind, placebo-controlled, intranasal amphetamine administration study conducted within an MRI scanner. Active state seed-to-voxel connectivity analyses assessed the effects of amphetamine, personality, subjective responses to amphetamine, and their interactions with mesocorticolimbic seeds on data collected during monetary incentive delay and go/no-go task performance. Results indicated that amphetamine administration largely disrupted brain activity as evidenced by connectivity values shifting toward no correlation among brain stem, striatal, and frontal cortex regions. Additionally, associations of impulsivity and connectivity between ventral tegmental and medial orbitofrontal as well as lateral orbitofrontal and putamen regions were inverted from negative to positive during the placebo and amphetamine conditions, respectively. Personality was unrelated to subjective responses to amphetamine. Results are interpreted as providing evidence of underlying differences in mesocorticolimbic circuitry being a potential target for requisite diagnostic and treatment strategies implicated with stimulant use disorders, but further research is needed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Young adults are particularly vulnerable to the negative effects of cannabis and the development of cannabis use disorder (CUD). CUD is largely defined by maladaptive decision-making, which often occurs while intoxicated in habitual cannabis users. This is problematic because cannabis and its major psychoactive chemical, THC, alter cognition and subjective experience. Pharmaco-TMS has informed mechanisms of movement; however no published research has examined the ability of TMS to modulate the acute effects of THC on decision-making dynamics, cognitive performance, and subjective effects in individuals with CUD. This ongoing double-blind, placebo and sham controlled study is enrolling young adults with CUD (n=6). On separate days, individuals receive randomized combinations of oral THC (0, 10, 30mg) and intermittent theta-burst stimulation (iTBS: sham, real). Decision-making and cognitive task performance and subjective effects are measured before dosing and directly following iTBS at the estimated THC concentration peak. Left dorsal lateral prefrontal cortex (DLPFC) stimulation targets are neuronavigated from individualized fMRI analyses isolating overlap between correct choice evaluation (decision-making task) and accurate high load working memory performance (N-Back). Primary measures are reinforcement learning modeled parameters from the decision-making task, accuracy from the N-Back task, and subjective drug effects on a visual analog scale. Preliminary analyses reveal trends in the ability of iTBS (real – sham) to modulate the effects of 30mg of THC on several outcomes (average±SEM). A modeled perseveration parameter during dynamic decision-making was lower (–0.48±0.21) and percent correct responding during high load working memory was greater (+7%±3.8), following iTBS. Several subjective measures also decreased following iTBS, including difficulty concentrating (–12%±14.5), feelings of high (–19.2%±17.2), and willingness to pay for drug (–12.5%±5.6). Together, these preliminary findings suggest that iTBS is a useful tool for studying the acute effects of THC on neurobehavioral outcomes relevant to understanding and treating CUD. Keywords: Cannabis, Learning, Neuronavigation, TMS