Refugees demonstrate high rates of post-traumatic stress disorder (PTSD) and other psychological disorders. The recent increase in forcible displacement internationally necessitates the understanding of factors associated with refugee mental health. While pre-migration trauma is recognized as a key predictor of mental health outcomes in refugees and asylum seekers, research has increasingly focused on the psychological effects of post-migration stressors in the settlement environment. This article reviews the research evidence linking post-migration factors and mental health outcomes in refugees and asylum seekers. Findings indicate that socioeconomic, social, and interpersonal factors, as well as factors relating to the asylum process and immigration policy affect the psychological functioning of refugees. Limitations of the existing literature and future directions for research are discussed, along with implications for treatment and policy.

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Two experiments used an associative blocking design to study the role of dopamine receptors in the nucleus accumbens shell (AcbSh) and core (AcbC) in fear prediction error. Rats in the experimental groups were trained to a visual fear-conditioned stimulus (conditional stimulus [CS]) A in Stage I, whereas rats in the control groups were not. In Stage II, all rats received compound fear conditioning of the visual CSA and an auditory CSB. Rats were later tested for their fear responses to CSB. All rats received microinjections of saline or the D1-D2 receptor antagonist cis-(z)-flupenthixol prior to Stage II. These microinjections targeted either the AcbSh (Experiment 1) or the AcbC (Experiment 2). In each experiment, Stage I fear conditioning of CSA blocked fear learning to CSB. Microinjection of cis-(z)-flupenthixol (10 or 20 μg) into the AcbSh (Experiment 1) had no effect on fear learning or associative blocking. In contrast, microinjection of cis-(z)-flupenthixol (10 or 20 μg) into the AcbC (Experiment 2) attenuated blocking and so enabled fear learning to CSB. These results identify the AcbC as the critical locus for dopamine receptor contributions to fear prediction error and the associative blocking of fear learning.

Conditioned stimuli (CSs) vary in their reliability as predictors of danger. Animals must therefore select among CSs those that are appropriate to enter into an association with the aversive unconditioned stimulus (US). The actions of prediction error instruct this stimulus selection so that when prediction error is large, attention to the CS is maintained and learning occurs but when prediction is small attention to the CS is withdrawn and learning is prevented. Here we studied the role of glutamate acting at rat nucleus accumbens shell (AcbSh) and core (AcbC) α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in this selection of danger signals. Using associative blocking and unblocking designs in rats, we show that antagonizing AcbSh AMPA receptors via infusions of 2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo[f]quinoxaline-2,3-dione (NBQX; 0.5 μg) prevents the unblocking of fear learning, whereas antagonizing AcbC AMPA receptors via infusions of NBQX (0.5 μg) prevents both the blocking and unblocking of fear learning. These results identify dissociable but complementary roles for AcbSh and AcbC glutamate acting at AMPA receptors in selecting danger signals: AcbSh AMPA receptors upregulate attention and learning to CSs that signal surprising USs, whereas AcbC AMPA receptors encode the predicted outcome of each trial.