There is evidence that bipolar disorders are associated with achievement-related cognitions such as setting high goals. A psychodynamic model, the manic defense hypothesis, postulates that a threat to fragile self-esteem triggers grandiosity and manic behaviors in vulnerable people. Vulnerability to bipolar disorders should therefore be positively associated with indicators of explicit hope of success (HS) and implicit fear of failure (FF). Using an online sample ( n = 252), we tested these hypotheses using the well-validated Hypomanic Personality Scale as risk indicator for mania, the Multi-Motive Grid for achievement motivation, controlling for current and lifetime depression. Contrary to expectations, we found that vulnerability for mania was significantly and positively related to implicit HS but not to FF after controlling for depression. All measures were self-report tools. Our results contradict the Manic Defense Hypothesis, but they are in line with the idea that achievement-related cognitions are of relevance to vulnerability in bipolar disorders. This is in line with research focusing on the role of the Behavioral Activation System in relation to vulnerability for mania.