Young adults who exhibit "bipolar phenotype" (BPP), defined as occasional episodes of mood
elevation and heightened activity, are at risk for several psychiatric disorders, including
problem use of drugs and alcohol. Mood elevation has been linked to higher alcohol
consumption and alcohol use disorders. Individuals with BPP show elevated lifetime prevalence
of alcohol use disorders (between 39%-61%), figures that exceed those reported in both major
depression and schizophrenia. Recently, the investigators demonstrated in a controlled
laboratory study that individuals with BPP (but not meeting criteria for full Bipolar I
Disorder), report dampened responses to a single dose of alcohol, compared to placebo. In the
current study, the investigators seek to extend these findings to determine if young adults
reporting BPP, based on a questionnaire, will exhibit reduced responses to other rewarding
stimuli, such as d-amphetamine and sweet tastes. The investigators hypothesize that the BPP
individuals will exhibit dampened subjective responses to stimulant and sweet taste rewards
compared to healthy controls.