Procedure
The study was approved by the Institute of Psychiatry (King's
College London) Ethics Committee, reference 011/00.Written informed
consent was obtained from the young people and their parents. Questionnaire
completion and saliva collection was undertaken at home.
Participants were asked to collect the samples on a Saturday when
they were able to wake up between 6:00 a.m. and 09:00 a.m. Samples
were taken using untreated Salivettes. Participants were instructed to
provide a sample of saliva immediately after waking, 15, 30, 45 and
60 min after awakening, then at 12:00, 16:00 and 20:00 hours. Standard
collection instructions were given, e.g., not to eat or brush teeth in the
hour prior to collection. Participants were asked to note the time they
took the samples and what they had been doing the previous hour before
each sample, including anything eaten or drunk. Participants not
complying with the collection instructions were not included. Samples
were kept in the refrigerator overnight before being returned to the
hospital. Cortisol was measured for a second time at six months after
the end of treatment, to allow time for consolidation of the treatment
response and for any effects on the HPA axis to occur. The same saliva
collection procedure was used at Time 2.