An integrative cognitive model proposed that individuals vulnerable to bipolar disorder (BD) assign extreme personal meaning to internal states. This research investigated the utility of the Hypomanic Attitudes and Positive Predictions Inventory as a cognitive risk measure for BD. Study 1 (N = 64; mean age 21.8 years, 42 female) explored whether students at cognitive risk had more extreme changes in mood and both self-reported and observer-rated bipolar-relevant symptoms during an interview task following a mood induction. The risk group did not respond differentially to the mood induction, but they spoke faster and dominated the conversation more during the interview task, self-reported greater activation, depression and negative affect, and scored higher on hypomanic personality, reward sensitivity, and dysfunctional attitudes. When controlling for other established cognitive measures, activation was still higher in the cognitive risk group at trend, and depression and negative affect were significantly higher. Activation, depression, and negative affect were still significantly higher in the cognitive risk group when controlling for reward sensitivity. Study 2 (N = 30; mean age 19.93 years, 21 female) complemented the experimental study with a 7 days diary study of everyday mood and behaviour. The risk group reported higher negative affect and bipolar-relevant symptoms. These results are consistent with the role of extreme appraisals of internal state in vulnerability to BD.