Clinical Trial of Propranolol for Seasonal Affective Disorder
Status:
Completed
Trial end date:
2007-01-19
Target enrollment:
Participant gender:
Summary
The purpose of this study is to determine what dose of a new timed-release tablet of the drug
propranolol will reduce secretion of the hormone melatonin in healthy volunteers. This study
will also determine whether suppressing melatonin will improve depressive symptoms in people
with seasonal affective disorder (SAD).
SAD (sometimes referred to as winter depression) is a condition in which people experience
depression as a result of seasonal variations in light. Human brains have a circadian
pacemaker that regulates many body functions. As the seasons change and light duration
varies, the circadian pacemaker regulates seasonal behavior by transmitting a signal of day
length to the pineal gland, which secretes the hormone melatonin. Melatonin secretion
increases in the winter as the duration of light decreases. Evidence suggests that the
melatonin signal of seasonal change is present in people with SAD but not in healthy
volunteers; thus there is a possibility that seasonal changes which influence the duration of
melatonin secretion control the course of illness in individuals with SAD. This study will
determine whether propranolol can shorten the duration of melatonin secretion and mimic the
effect of summer days to improve symptoms of depression in people with SAD.
Healthy volunteers will be admitted to the hospital for about 2 days. The volunteers will
receive either propranolol or placebo (an inactive pill) before going to bed and upon
awakening. Blood samples will be collected at various times throughout the study.
Participants with SAD will be interviewed periodically on an outpatient basis to determine
the onset of depression in the fall or winter. Two weeks after depressive symptoms arise,
participants will begin treatment with either propranolol or placebo. At the beginning of the
treatment, participants will be hospitalized for about 2 days and will have blood collected
at various times. During the hospital stay, participants will continue treatment with either
propranolol or placebo in the morning and at night; all participants will receive propranolol
at some point during the study. Participants will be interviewed weekly for 4 weeks.
Premenopausal women with or without SAD will keep a record of their menstrual cycles and will
use a urine test kit to identify the time of ovulation during the month before and after
admission to the hospital.