Within a period of 26 weeks, in both the MI and the
HE group, patients were offered 8 sessions of either MI
or HE. When the therapist judged there were problems to
keep patients engaged in the interventions or in case of
practical barriers, fewer sessions were given, with a minimum
of 5 sessions. Less than 5 sessions was counted as
a dropout. The session duration varied between 20 and
45 minutes, depending on the attention span of the participant
during a session. Therapists were not otherwise
involved in the treatment of participants. Patients were
told they would be allocated to 1 of 2 active interventions
and were not told which was the experimental condition.
Next to the interventions, participants received care
as usual, consisting of functional assertive community
treatment for patients treated on an outpatient basis and
routine clinical care for hospitalized patients.
Before starting the intervention, a baseline assessment
(T0) was performed. Participants were interviewed
again after the intervention was completed (T1) and
after 6 months follow-up (T2). All assessments were performed
by trained psychologists and psychiatrists, who
were masked to which condition a patient was allocated;
a coordinator assigned the interventions and assessments
to different researchers, ensuring that the interventions
and the assessments were never performed by researchers
appointed in the same facility. Data on interventions and
assessments were stored separately.
Participants received a travel expenses compensation
of 5 euro for each intervention session or assessment in
which they participated. The study was approved by the
Medical Ethical Committee of the Academic Medical
Centre, Amsterdam.