Ilardi and Craighead (1994) observed that 60-70% of symptom improvement in
cognitive behavioral therapy (CBT) occurs in the first 4 weeks, and they as
sumed that cognitive modification techniques are not extensively applied in
these weeks. They thus concluded that Beck's cognitive hypothesis of CBT c
annot explain this early improvement. However, studies have shown that cogn
itive modification techniques are applied extensively in early sessions. Al
so, in most CBT studies there have been two sessions per week for the first
: 4 weeks and 1 session per week thereafter Thus, 40-60% of CBT sessions in
studies occur in the first 4 weeks, which arguably is enough therapeutic t
ime for cognitive techniques to have a substantial effect on symptoms. Fina
lly, Ilardi and Craighead's method assumes homogeneity among the patients'
time courses, which is inconsistent with empirical data. We conclude that s
ymptom change time course data do not contradict Beck's cognitive hypothesi
s.