Acceptance and Commitment Therapy as a self-help intervention for adults with mild to moderate psychological distress: a randomized controlled trial

Many adults in the Netherlands suffer from mental disorders, such as depression
and anxiety. These disorders have a high negative impact on the quality of
life. They also cause high economic costs and increased use of health services.
Besides treatment, there is more evidence that also prevention is a
cost-effective alternative to decrease the incidence of mental disorders.

The University of Twente therefore developed the preventive group intervention
*Voluit Leven*, based on Acceptance and Commitment Therapy for adults with mild
to moderate psychological distress. The group intervention was evaluated in a
randomized controlled trial with 93 adults with psychological distress. The
results showed that the intervention group, compared with a wait list group,
had decreased psychological distress (depression and anxiety), fatigue and had
increased psychological flexibility and mental health.
This intervention is now developed as a self-help book based on Acceptance and
Commitment Therapy and mindfulness, whereby people can work independently
through the book with supportive counselor contact.

The purpose of the study is to conduct a randomized controlled trial with the
self-help intervention *Voluit leven* for adults with mild to moderate
psychological distress.
The research question is: What are the effects of the preventive self-help
intervention *Voluit leven* for adults with mild to moderate psychological
distress, based on Acceptance and Commitment Therapy, on psychological
distress, fatigue, mindfulness, psychological flexibility and mental health as
compared to a waitlist group?

A randomized controlled trial with three parallel groups:
1. Experimental condition: the self-help intervention *Voluit leven* with
process monitoring by a counselor with e-mail contact.
2. Experimental condition: the self-help intervention with process monitoring
and personal support by a counselor with e-mail contact.
3. Control condition: a waitlist group, the participants receive the self-help
intervention after three months.

Selp-help intervention with process monitoring by a counselor : The self-help
intervention *Voluit leven* is a book with 9 modules that can be followed in 9
weeks. The intervention is monitored by counselor e-mail contact.
Self-help intervention with process and personal support by a counselor: This
is the same intervention described above, but the counselor provides also more
personal support.
Waitlist group: The participants on the waitlist do not receive the
intervention.

Participants have to work about 2 a 4 hours per week in the self-help book.
Thereby, the participants are asked to fill out questionnaires at five moments.
This gives a burden of about 4 hours. We expect not many risks for the
participants, because there are relative healthy population.