Background of the study:
The symptoms of posttraumatic stress disorder (PTSD) follow exposure to a traumatic event and
are accompanied by significant functional limitations. PTSD is very common: a multinational
study shows a lifetime prevalence of 3.9%. Effective treatment options exist for people with
PTSD, with Eye Movement Desensitization and Reprocessing (EMDR) and Prolonged Exposure (PE; a
specific form of trauma-focused Cognitive Behavioral Therapy, T-CBT) both listed as
first-choice interventions in the Dutch standard of care for psychotrauma and stressor
related disorders. About 40% of patients with PTSD do not benefit sufficiently from either of
the aforementioned guideline treatments and about 18% of patients do not complete a
trauma-focused treatment (treatment dropout). Knowledge about general predictors of treatment
success in psychotherapy is limited, making it currently impossible to predict which patient
will or will not benefit from which specific psychotherapeutic treatment (i.e., EMDR vs. PE).
Little scientific knowledge exists about optimal follow-up treatment when patients
insufficiently benefit from their initial treatment. For patients who drop out (e.g. from
inability to tolerate exposure to traumatic memories) or do not benefit from exposure
therapies, an alternative is to switch not to another proven effective trauma-focused
intervention, but to a non-trauma-focused intervention. A suitable non-traumafocused
treatment is Interpersonal Psychotherapy. Previous research suggests that IPT can be an
effective first-line treatment option, but the effectiveness of IPT as a second treatment
step for people with PTSD who have not responded to a trauma-focused psychotherapy has never
been investigated. We hypothesize that IPT will yield greater symptom reduction and less
dropout for patients with PTSD who do not respond to a course of trauma-focused psychotherapy
compared to switching to another trauma-focused therapy.
Study population:
Subjects are recruited from Dimence, a mental health institution in the Netherlands. Subjects
are recruited from patients who register for outpatient treatment within the Dimence division
"Specialistic Diagnostics and Treatment" with a primary diagnosis of PTSD. It concerns adults
between 18 and 65 years old, both men and women.
Intervention:
Half of initially non-responsive patients will be treated with the non-trauma-focused
intervention interpersonal therapy (IPT) in phase 2 of the study. The first and second phases
will offer the trauma-focused treatments Prolonged Exposure and EMDR.
Interpersonal Psychotherapy (IPT) does not target the memories of a traumatic event but
the interpersonal consequences of trauma, seeking to improve affective and interpersonal
functioning that PTSD symptoms have disrupted. PTSD following a traumatic life event
produces social withdrawal and a blunted, inhibited emotional life, disrupting
interpersonal functioning. IPT helps benumbed patients recognize and tolerate their
feelings so they can use them to handle their social environment, determine who is
trustworthy, and mobilize protective social supports. IPT addresses patient emotions and
their relationship to interpersonal interactions. As patients recognize their feelings,
the therapist helps patients to name, normalize, and use their feelings rather than
seeing them as an additional threat.
In Prolonged Exposure, patients directly confront traumatic memories and cues and learn
to expose themselves to terrifying but not dangerous stimuli to achieve habituation or
extinction. The current study will use a protocol-based treatment of Cognitive
Behavioral Therapy for PTSD that includes imaginal and in vivo exposure.
In EMDR, patients are distracted from the traumatic memories by a dual attention task,
usually using eye movements. This study will use a protocolled EMDR treatment for PTSD.
Nature and extent of the burden and risks associated with participation, benefit and group
relatedness (if applicable):
Major adverse events are not expected as these have not been documented in previous studies.
The greatest burden on subjects is completing the questionnaires necessary to answer the
primary research questions. In phase 1, this totals approximately 10.5 hours (with baseline
measurement the most extensive and subsequent weekly measurements); for patients treated for
an additional 8 weeks in phase 2, completing the questionnaires takes approximately another 6
hours. A patient participating in both treatment phases therefore spends a total of
approximately 16.5 hours completing assessments. The prescription of patients taking
medication must be stable prior to the study, and then not changed during the study, unless
necessary due to a crisis or serious side effects. Patients receive treatment sessions twice
a week, which is relatively frequent compared to usual treatment, but research shows that
dropout is lower with two weekly sessions. Study participation further assures patients that
the treatments they receive are performed as intended by the therapy-developer because
therapists receive supervision and checks are made to ensure treatment integrity.
