Differential Responses to Drugs and Sweet Tastes
Condition: Bipolar II Disorder
Study type: Interventional
Phase: Phase 1

Summary: 
      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.
    

Detailed description: 
      This study will extend the understanding of risk factors for drug or alcohol misuse, or other
      reward-related behaviors. The investigators previously showed that individuals who report
      occasional feelings of high energy and excitability experience less effect from a single dose
      of alcohol, compared to people who have not experienced these effects. Now the investigators
      wish to determine if this dampened response also occurs with other rewards, namely feelings
      of wellbeing after a dose of amphetamine, or liking of a sweet solution. Individuals who
      exhibit the BPP (i.e., periods of excitability) also are more likely to develop alcohol
      problems, substance misuse, and weight gain and obesity. Therefore, the investigators will
      test the working hypothesis that young adults who report having these experiences, based on a
      questionnaire measure (i.e., BPP individuals) will show dampened subjective responses to both
      single oral doses of amphetamine or sweet palatable tastes. The investigators will also
      obtain objective measures (e.g. Respiratory Sinus Arrhythmia and heart rate) to amphetamine
      and sweet taste, to establish whether the dampened subjective response extends to
      physiological indices as well. This study will extend the previous literature regarding the
      blunted effects of alcohol in BPP individuals and will suggest possible mechanisms that
      promote broader addictive behaviors in individuals with mood disturbance. Importantly, the
      investigators are proposing to test individuals at a relatively young age, 18-19 years. This
      is important to identify a risk factor, that is thought to pre-date use of drugs. In older
      participants, it would be difficult to separate the role of the pre-existing trait from the
      effect of habitual drug or alcohol use that escalates markedly after age 20.
    

Intervention name(s): Placebo oral capsule; d-amphetamine 10 mg oral capsule; d-amphetamine 20 mg oral capsule
Intervention type(s): Drug; Drug; Drug
Intervention description(s): Placebo oral capsule; d-amphetamine 10 mg oral capsule; d-amphetamine 20 mg oral capsule
Intervention MeSH terms: Amphetamine; Dextroamphetamine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Study will track participants in two assigned groups (participants that exhibit either High or Low Bipolar II/Hypomanic phenotypes)
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science