Primates as animal models for CPP research

Conditioned place preference (CPP) is a widely used method to assess the rewarding effects of drug and non-drug stimuli. This paradigm has been successfully demonstrated across several species, although rats seem to be the most prevalent model. Given the significant neurophysiological discrepancies between rodents and humans, as well as the technical and ethical limitations of research involving the latter, CPP protocols employing nonhuman primates (NHPs) have been reported in the past 25 years. In this review, we examined the literature on CPP studies using NHPs, including a variety of unconditioned stimuli. A total of 14 studies, involving macaques or marmosets, met the inclusion criteria. Overall, findings indicate that CPP effects were consistently achieved using cocaine, methylphenidate (MPH), and highly palatable food in marmosets, as well as with morphine and methamphetamine (METH) in macaques. Despite the relatively low number of reports, the available evidence suggests that NHP species represent viable and versatile alternatives for CPP research, offering greater translational validity compared to rodent models due to their closer neurobiological, cognitive, and behavioral similarities to humans.