Abstract
RATIONALE: One risk factor for alcohol and substance misuse is hypomanic experiences, or periods of mood elevation. Young people who report hypomanic states are more likely to develop bipolar disorder (BP), and BP and other mood disorders increase the risk of addiction. We recently reported that young adults with a history of mood elevation experience less subjective effects from a low dose of alcohol, which may be predictive of future alcohol use. The finding with alcohol raised the question of whether this dampened response to a drug also applies to other drugs, such as amphetamine. OBJECTIVE: This study assessed responses of d-amphetamine in healthy young adults with varying experiences of mood elevation, as measured by the Mood Disorders Questionnaire (MDQ). METHODS: Healthy 18-19-year-olds (N = 30) with a range of MDQ scores participated in three 4-h laboratory sessions in which they received placebo, 10 mg, or 20 mg d-amphetamine. They completed mood questionnaires and cardiovascular measures. RESULTS: Individuals with higher MDQ scores reported less stimulation and euphoria after 10 mg, but not 20 mg, d-amphetamine, than individuals with lower scores. MDQ scores were not related to cardiovascular responses to the drug. CONCLUSIONS: A history of mood elevation experiences or hypomania states is related to dampened response to a low dose of a psychostimulant drug, extending previous findings with dampened response to alcohol. This phenotype for mood disorders of dampened responses to drugs may contribute to risk for subsequent drug use or misuse.