Lever-press duration as a measure of frustration in sucrose and drug reinforcement

Rationale Currently there is little research into the role of frustration in substance use disorders despite research showing that frustration tolerance in humans is associated with a lower likelihood of developing substance use problems, better outcomes in recovery, and fewer relapses. Objective In order to address this need, our studies use a rat model to focus on frustration-related behavior in natural reward and addiction-related behavioral procedures. Frustration is defined as when a subject is unable to achieve a reinforcer, receives less of a reinforcer than anticipated, or has to work harder to achieve a reinforcer. Results In these studies, bar-press durations increase when rats are in a state of frustration during self-administration of sucrose, fentanyl, or cocaine. Conclusions These data also show that average bar-press durations do not correlate with the number of bar presses, meaning that press duration is an independent measurement that represents a behavioral construct distinct from craving, which is typically measured with number of bar presses. Essentially, these results support that bar press durations can be used as a real-time measure of frustration as a 4th major facet of addiction-related behavior, adding to craving, impulsivity, and habit.