Purpose of review: What is the relationship between rationality and mental health? By considering the psychological literature on depressive realism and unrealistic optimism it was hypothesized that, in the context of judgments about the self, accurate cognitions are psychologically maladaptive and inaccurate cognitions are psychologically adaptive. Recent studies recommend being cautious in drawing any general conclusion about style of thinking and mental health. Recent findings: Recent investigations suggest that people with depressive symptoms are more accurate than controls in tasks involving (...) time perception and estimates of personal circumstances, but not in other tasks. Unrealistic optimism remains a robust phenomenon across a variety of tasks and domains, and researchers are starting to explore its neural bases. However, the challenge is to determine to what extent and in what way unrealistic optimism is beneficial. Summary: We should revisit the hypothesis that optimistic cognitions are psychologically adaptive, whereas realistic thinking is not. Realistic beliefs and expectations can be conducive to wellbeing and good functioning, and wildly optimistic cognitions have considerable psychological costs. (shrink)

In this thesis I propose a new way of understanding depressive illness as not exclusively harmful, but as related to particular, empirically evidenced, epistemic and pragmatic benefits for the subject, alongside the associated costs. For each of the benefits considered, I provide and concisely analyse the empirical evidence both in its favour and against it, suggest ways in which these benefits could apply in the circumstances presented, discuss some outstanding problems for that application as stated, and describe potential implications. The (...) issues discussed involve topics in cognitive psychology as well as in ethics, which I regard as complementary to the debate. I take the view that depression related phenomena such as low mood, low self-esteem, and mood-congruent delusions offer potential benefits to a subject under certain circumstances, but not under others. In discussing the hypotheses presented, I argue for a more complex view of depression, which includes its potential epistemic and pragmatic benefits as well as its costs and I propose possible directions for future research. (shrink)