Zusammenfassung der Ressource
Avery et al
- Aim: To investigate and compare the
effectivness of six weeks dawn simulation, bright
light therapy, or a placebo dawn simulation
condition (a dim red light) to act as the control
group, in patients with SAD during the winter.
- Research method:
- Longitudinal lab experiment
- 95 self-selected participant (volunteers
recruited through advertisements).
- Double blind control:
- Participants were unaware of the
comparison between the three treatments.
- Participants were rated and evaluated
weekly by experienced, board-certified
psychiatrists who did not known which
treatments the participants were assigned.
- Independent variable was the type of
treatment the participants were
exposed to.
- Dependent variable in the effectiveness
of the treatment measured by remission
and response rates.
- Procedure:
- Recruited participants are tested to
determine whether they are
hypersomnic winter depressives.
- For 7 weeks participants visit the clinic
weekly for assessment and are to sleep only
between the hours of 9pm and 6am and
keep a daily log of their sleep each week.
- After the first week of the study
participants are randomized to three
treatment groups: dawn simulation,
bright light therapy and a placebo dawn
simulation (as the control group).
- Participants are asked to sleep only between
9pm and 6am, to avoid sunlight and to avoid
certain foods and activities.
- Researchers analyse ratings, symptoms
and responses of participants that the
psychiatrist reported.
- Findings:
- Participants who were assigned to the dawn
simuation treatment showed significantly more
remission and response rates than participants who
experienced the bright light therapy and the placebo
conditions.
- Evaluate study:
- Strengths of the study:
- Well controlled. The study contains an
ample amount of dependent and
independent variables suitable for being
able to triangulate the experiment.
- Replicable, can be triangulated.
- Weaknesses of the study:
- Low ecological validity. Many
restrictions were placed on the
participants during the study
- Low cross-cultural validity; a very large
percentage, about 85% of participants were
Caucasian.
- Gender bias. Only 4 males in each study
conducted, compared to 27-30 females.
- Evaluative findings:
- Cannot be generalised to all SAD patients;
the only type used were those suffering
from hypersomnia. Other types of SAD
were not considered in the study.
- Treatment in usually rapid in results,
patients can feel effects within the first
few days of treatment.
- Some side effects, Nausea was
common, as well as headaches in
patients undergoing bright light therapy.
- Dawn simulation seemed to have the
lest amount of side effects and the larger
success rate of the three groups.