Intervention
The minimal intervention consisted of a booklet with guided self-instruction based on the CBT for
CFS protocol. All patients had fortnightly contact with a trained psychiatric nurse via e-mail.
Nurses sent a reminder when patients did not respond every 2 weeks. During therapy, patients
change cognitions and behaviours that are assumed to perpetuate fatigue and disability.
Psychiatric nurses introduced the minimal intervention booklet and provided instructions to
the patient to complete the intervention within 6 months. All patients had a face-to-face
evaluation after completion of the second assessment (at 6 months) with the psychiatric nurse
who delivered the therapy.
If patients were still severely fatigued, they were referred to a CBT therapist within the MHC for
additional face-to-face CBT for CFS. This additional face-to-face CBT was the second step of
stepped care. Following the protocol (Knoop and Bleijenberg, 2010), a full therapy would consist
of 12 to 14 sessions over a period of 6 months. However, dependent on the progress made during
the minimal intervention, the therapist decided which elements of the protocol should be
discussed during the face-to-face CBT (Tummers et al., 2010). Detailed information on the
minimal intervention, and the training and supervision of the nurses and the CBT therapists, can
be read in the Supplementary Material.