Sleep Therapy for People with Prolonged Grief Disorder and Insomnia Disorder

Recent studies provided evidence that insomnia symptoms in bereaved people may
constitute an important (causal) risk factor for severe and persistent grief,
termed prolonged grief. This strongly suggests that insomnia is a relevant
treatment target for prolonged grief disorder. However, high-quality clinical
experiments targeting insomnia in people with prolonged grief disorder and
comorbid insomnia are lacking. We expect that cognitive behavioral therapy for
insomnia (CBT-I) in people with both prolonged grief disorder and insomnia
disorder will reduce both symptoms of insomnia and symptoms of prolonged grief

The primary objective is to evaluate whether CBT-I in people with both insomnia
and prolonged grief disorder alleviates both insomnia and prolonged grief
symptoms. The secondary objective, is to evaluate whether CBT-I is an effective
treatment of insomnia in people with comorbid prolonged grief disorder.

We plan to conduct a replicated two-phase single-case experimental design
study, testing the efficacy of CBT-I in participants with prolonged grief
disorder and comorbid insomnia. We choose this design as it offers the
possibility to study causal mechanisms with a limited sample size.
Participants can enroll for the study through our website
(www.onderzoekrouw.nl). They are invited to complete a screening questionnaire
for prolonged grief disorder and insomnia disorder. Participants who score
above the established cut-off scores on the Insomnia Severity Inventory (ISI)
and the Traumatic Grief Inventory Self-Report Plus (TGI-SR+) will be invited
for a diagnostic interview. Following the diagnostic interview, the baseline
phase (waiting period) will start. Participants will be randomly assigned to
different lengths of waiting periods based on a computer-generated list. The
baseline phase can range between five and 14 weeks. During this phase,
participants will be asked weekly, to complete a short online questionnaire on
insomnia (ISI) and PGD symptoms (TGI-SR+) experienced during the prior week.
The weekly assessment of insomnia and PGD symptoms will continue during the
treatment phase. Insomnia and prolonged grief symptoms will also be reassessed
at a three-month post-treatment follow-up.

We will provide all participants with CBT-I, the first choice treatment for
insomnia (Riemann et al., 2023). CBT-I consists of 6-7 weekly individual,
face-to-face sessions of 1-2 hours according to the Dutch CBT-I protocol
(Verbeek & van de Laar, 2023). Depending on the location of the participant,
these sessions can be held either at the Heymans Institute or online using a
video conference program. At four weeks post-treatment, a booster session will
be planned to evaluate sleep health and, if necessary, repeat certain treatment
components. Prior to CBT-I, participants will be randomly assigned to waiting
periods between five and 14 weeks (the baseline phase).

The current study will be of minimal burden and negligible risk to
participants. Exclusion are used to minimize risks to participants. In addition
to the clinical interview at the start of the study, which is standard practice
in mental health care, participants will be asked to fill out 26 weekly
questionnaires consisting of 19 multiple-choice questions (< 5 minutes to
complete) for which they will receive 5 euros per assessment. These
questionnaires will also be used as an evaluation of the treatment. Finally,
participants will be asked to complete a follow-up questionnaire, three months
after the last treatment session. This questionnaire will take no more than 5
minutes to complete and results in an additional payment of 50 euros.
There are minimal risks/burden associated with CBT-I. CBT-I is the gold
standard treatment for insomnia worldwide, has been investigated in numerous
studies, and is recommended in clinical practice (see: Riemann et al., 2023).
An important component of CBT-I is stimulus control therapy. During stimulus
control therapy participants are instructed to leave the bedroom when noticing
they are not falling asleep and to return only when feeling sleepy.
Furthermore, participants are instructed to refrain from any activity other
than sleep and sex in the bedroom. For elderly and mobility-impaired
participants, getting out of bed during nighttime might increase the risk of
falling. These participants are therefore not instructed to get out of bed.
Another important component of CBT-I is sleep restriction therapy, in which
patients are instructed to restrict their bedtimes to their average sleep time.
Reducing sleep times could lead to certain risks. Specifically, this
intervention is associated with mild short-term side effects such as
performance impairment and reduced reaction times (Kyle et al., 2014). These
side effects are similar to what is normally observed in insomnia patients.
Therefore, for reasons of safety, participants are instructed to spend a
minimum of 5 hours in bed each night and to refrain from driving a car or
operating heavy machinery if they feel excessively sleepy during the early
stages of sleep restriction therapy. Importantly, sleep restriction is a potent
intervention technique that may lead to some side effects at first, but also
leads to an amelioration of such experiences over time.
Additionally, minimal risks/burden are associated with the repeated
measurement of symptoms of prolonged grief disorder and insomnia. This repeated
measurement might elicit some negative feelings in participants. However, it is
our experience from prior survey research among hundreds of bereaved adults,
that they generally find it comforting to know that their grief can contribute
to something positive, such as scientific knowledge. Nevertheless, to further
reduce the risk of eliciting negative feelings, we will only use validated
questionnaires applied successfully before in the bereaved population.