The impact of CBT and ACT models using psychology trainee therapists: a preliminary controlled effectiveness trial.

Lappalainen et al. (2007) compared two talk-therapy styles run by brand-new therapists. One style was ACT, which teaches clients to accept hard thoughts and act on their values. The other style was classic CBT, which teaches clients to change or challenge thoughts.

Twenty-three adults with mixed problems (anxiety, depression, stress) were picked at random for ACT or CBT. Each client got eight weekly sessions from psychology grad students who had never treated clients before.

Clients in ACT improved more overall than clients in CBT. The ACT group also got better at accepting upsetting thoughts, and this skill helped explain their symptom drop.

In plain numbers, ACT clients ended with lower scores on the Brief Symptom Inventory than CBT clients. The difference was medium-large, even though the therapists were still in training.

Pahnke et al. (2014) later used ACT in a special-school group for teens with autism. They also saw gains—less stress, more prosocial acts—showing ACT can travel from adult clinic to classroom.

Fahmie et al. (2013) ran a mindfulness therapy (MBT-AS) for autistic adults and found similar mood benefits. Their RCT design mirrors Raimo’s, but MBT-AS focuses on present-moment awareness while ACT adds values-based action.

Bhaumik et al. (2008) tested a CBT twist for chronic fatigue and still saw good results. This keeps CBT in the game; Raimo’s findings don’t erase CBT—they just hint ACT may give rookie therapists a faster win with mixed-anxiety cases.

If you supervise students or new RBTs moving into talk therapy, start them with ACT scripts and acceptance drills. The study says even beginners can produce stronger client gains than with standard CBT, so you can shorten the learning curve while keeping quality. Try adding one brief values exercise and one acceptance metaphor in your next session plan and watch if clients engage faster.