Drug addiction is widely recognized to afflict some but not all individuals by virtue of underlying risk markers and traits involving multifaceted interactions between polygenic and external factors. Remarkably, only a small proportion of individuals exposed to licit and illicit drugs develop compulsive drug-seeking behavior, maintained in the face of adverse consequences and associated detrimental patterns of drug intake involving extended and repeated bouts of binge intoxication, withdrawal and relapse. As a consequence, research has increasingly endeavored to identify distinctive neurobehavioral mechanisms and endophenotypes that predispose individuals to compulsive drug use. However, research in active drug users is hampered by the difficulty in categorizing putatively causal behavioral traits prior to the initiation of drug use. By contrast, research in experimental animals is often hindered by the validity of approaches used to investigate the neural and psychological mechanisms of compulsive drug-seeking habits in humans. Herein, we survey and discuss the principal findings emanating from preclinical animal research on addiction and highlight how specific behavioral endophenotypes of presumed genetic origin (e.g. trait anxiety, novelty preference and impulsivity) differentially contribute to compulsive forms of drug seeking and taking and, in particular, how these differentiate between different classes of stimulant and non-stimulant drugs of abuse.The authors acknowledge funding support from the UK Medical Research Council (grants G9536855; G0701500; G0802729), the Newton-Cambridge Trust and the Wellcome Trust (grant WT109738MA). The Behavioural and Clinical Neuroscience Institute at Cambridge University is supported by a core award from the Medical Research Council (G1000183) and Wellcome Trust (093875/Z/10/Z).This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/gbb.1226
