Individual differences in affective learning have been linked to mental health variability. This thesis aimed to contribute to our understanding of the mechanisms underlying this association. We conducted four studies using a variety of methodologies, including questionnaires, learning tasks, eye-tracking, olfactometry, and fMRI. We found evidence for an association between mental health problems related to anxiety and a decreased tendency to track the perceptual properties of appetitive expected outcomes. A separate study showed that two types of habitual behavior were differentially associated with mental health: routine was associated with compulsivity, while automaticity was associated with problematic media use. Finally, we found no evidence for an effect of stress on the integration of Pavlovian and instrumental processes. Overall, these findings support the proposition that understanding affective learning has the potential to shed light on mechanisms giving rise to mental health difficulties, and suggest further avenues for research.