Addiction Biomarkers: Dimensional Approaches to Understanding Addiction

Abstract

Trends towards dimensional approaches in understanding psychiatric disorders may also be applied to addictive disorders. Advances in our understanding of the neurobiology of addiction can inform these efforts. Furthermore, dimensional approaches to addiction, such as the proposed Addictions Neuroclinical Assessment (ANA), may be used in identifying novel addiction biomarkers, and refining ones that currently exist. These biomarkers, derived from both an understanding of the neurobiology of addiction and behavioral phenotypes, represent a departure from traditional markers of alcohol-relevant biomarkers, such as tests of liver function (LFTs). We posit that a potential addictionrelevant biomarker is reinforcer pathology, found to be relevant across addictions to different substances, and which may offer a target for modification through the use of episodic future thinking.

Impaired frontostriatal functional connectivity among chronic opioid using pain patients is associated with dysregulated affect

“…Repeated exposure to drugs of abuse produces glutamatergic neuroplasticity in frontostriatal circuitry, which serves to bias reward processing towards drug consumption and away from the pursuit of natural rewards . Resting‐state studies have also implicated the frontostriatal vmPFC→NAc pathway in impulsivity, compulsivity, adaptive decision making, and the regulation of hedonic tone and pain .…”

“…Negative emotionality is included as one of the core domains in the newly developed Addictions Neuroclinical Assessment and is considered as one of the primary drivers of relapse during withdrawal . Negative affect is traditionally considered to be mediated through frontolimbic pathways (ie, anterior cingulate cortex/vmPFC→amygdala) with frontostriatal circuitry involved in ventral‐striatal inhibition; yet previous fMRI investigations into associations between frontostriatal activation, connectivity, and affect in addiction have primarily focused on appetitive processing and revealed associations with positive affect (and the lack thereof, ie, anhedonia or hypo‐hedonia) .…”

A Reinforcer Pathology perspective on relapse

“…Indeed, the novel and still developing theory, Reinforcer Pathology 2.0, was informed by interventions that both increased and decreased delay discounting, as well as the frequently observed phenomenon during addiction development that, as a substance increases in value, other temporally extended prosocial reinforcers such as education, employment, and relationships lose value (Koob & Volkow, 2016;Lemley et al, 2016). Specifically, Reinforcer Pathology 2.0 proposes that delay discounting, a measure of the temporal window of reinforcer integration (i.e., how far in the future one can consider and integrate into the present) is a determinant of reinforcer value (Kwako, Bickel, & Goldman, 2018). In other words, Reinforcer Pathology 2.0 moves from a notion that substance dependence is the result of two independent forces (e.g., excessive discounting and excessive valuation of reinforcers) to the notion that excessive discounting (representing a limited temporal window of integration) is a determinant of excessive valuation of addictive substances (not the interaction).…”

Neuroimaging, neuromodulation, and population health: the neuroscience of chronic disease prevention

“…Substances and some food items deliver a brief, intense reinforcer with immediate and reliable effects, whereas prosocial reinforcers such as ones' work or relationship with others function at lower intensity, are more variable in availability, and have greater value when considered over longer time periods. 110 If the temporal window associated with delay discounting is constricted (high discount rates), then prosocial reinforcers will be viewed over a short time frame and valued less than if viewed over a longer period. Thus, a constricted temporal window increases the relative reinforcing value of substances as the competing prosocial reinforcers are valued less.…”

“…EFT, derived from the science of prospection, refers to simulating possible prospective events in one's personal future. 110 Prospection entails prefrontal brain structures and contributes to the science of cognitive motivation. 115 Prospection deficits have been observed in those with alcohol use disorders.…”