OPQRST(U): Integrating substance use disorders or "Use" into the medical history.

Substance use disorders (SUDs) are pervasive in the United States, with 20.1 million cases in 2016, of which only 19% receive treatment. SUDs permeate all medical specialties and should be considered in the differential diagnosis of every chief complaint. Acknowledging the salience of SUDs provides a unique opportunity for early identification and intervention. Thus, SUDs should be reflected prominently in the history of the present illness rather than in the social history. To this effect, we propose the inclusion of Use (U) in the history of present illness and incorporating "U" into the pedagogical mnemonic of OPQRST that is commonly used in medical training. Obtaining this history will help determine if and which abused substances may be contributing to the chief complaint. We also suggest the incorporation of an additional acronym, SORTED, to account for the various domains of Use, including Street (illicit drugs), OTCs (over-the-counter medications), Rx (prescriptions, including nonmedicinal use of pharmaceutical drugs), Tobacco (including e-cigarettes), EtOH (alcohol), and Dietary (caffeine, vitamins, and herbal supplements) agents. We discuss how utilizing OPQRSTU will help reshape the way medical students think about SUDs and will facilitate detection and diagnosis of all domains of SUDs.

Dopaminergic lesions of the dorsolateral striatum in rats increase delay discounting in an impulsive choice task.

Dysregulated dopamine transmission in striatal circuitry is associated with impulsivity. The current study evaluated the influence of dopaminergic inputs to the dorsolateral striatum on impulsive choice, one aspect of impulsive behavior. We implemented an operant task that measures impulsive choice in rats via delay discounting wherein intracranial self-stimulation (ICSS) was used as the positive reinforcer. To do so, rats were anesthetized to allow implanting of a stimulating electrode within the lateral hypothalamus of one hemisphere and bilateral dorsal striatal injections of the dopaminergic toxin, 6-OHDA (lesioned) or its vehicle (sham). Following recovery, rats were trained in a delay discounting task wherein they selected between a small ICSS current presented immediately after lever pressing, and a large ICSS current presented following a 0 to 15 s delay upon pressing the alternate lever. Task acquisition and reinforcer discrimination were similar for lesioned and sham rats. All rats exhibited an initial preference for the large reinforcer, and as the delay was increased, preference for the large reinforcer was decreased indicating that the subjective value of the large reinforcer was discounted as a function of delay time. However, this discounting effect was significantly enhanced in lesioned rats for the longer delays. These data reveal a contribution of dopaminergic inputs to the dorsolateral striatum on impulsive choice behavior, and provide new insights into neural substrates underlying discounting behaviors.