<p>The symptoms and associated features of mental disorders can include profound and often debilitating effects on behaviour, mood and attitude, social interactions, and engagement with the world more generally. One area of living that is closely tied to mental disorder is that of our intellectual lives, pursuits, and projects. If the symptoms and features of mental disorders can have significance when it comes to intellectual activity, however, it is plausible that they can also have significance when it comes to epistemic-normative questions. I.e., questions concerning whether a person&#xa0;conducts their intellectual activities as they should and what is the normative status of the outputs of those activities. In this paper, I introduce the concepts of <i>epistemic health</i> and <i>epistemic disorder</i> as tools to examine and help understand the relationship between mental health, mental disorders, and epistemic agency. To do so, I explore the connections between a key aspect of our epistemic lives, <i>epistemic self-trust</i>&#xa0;and its associated maladjustments, <i>self-distrust</i> and <i>excess self-trust</i>, and a specific mental disorder, <i>bipolar disorder</i>. Drawing upon empirical work on metacognition and extracts from Kay Redfield Jamison’s bipolar memoir An Unquiet Mind, I argue that there is a significant association between bipolar disorder, the symptoms of depression and mania, and the risk of self-distrust and excess self-trust. In this light, I suggest that consideration of this relationship helps us to recognise how self-trust can be the site of a significant vulnerability with respect to one’s epistemic agency that merits the label of an epistemic disorder.</p>