Tackling anxiety disorders: A working memory intervention

An anxiety disorder consists of an ongoing and severe kind of anxiety without
the presence of a realistic threat. There are different kinds of anxiety
disorders, for example panic disorders, agoraphobia, social phobia, generalized
anxiety disorders (GAD) and obsessive compulsive disorders (OCD). Together with
mood disorders and substance use disorders, anxiety disorders are among the
most prevalent mental disorders (Brysbaert, 2006). The World Health
Organisation (WHO; 2010) estimates that around 12% of the population suffers
from clinical anxiety every year. The life of people with an anxiety disorder
changes significantly. Symptoms of anxiety are frequently associated with a
variety of physical symptoms like sweating, heart palpitations and trembling.
Anxiety causes a great deal of distress to the patients and to their families.
In addition, anxiety disorders cause significant economic costs. For example,
these disorders were costing the Netherlands 285,6 million euros in 2005 (Van
Wieren, Schoemaker, & Van Balkom, 2010). Treatment strategies for anxiety
disorders include cognitive therapy, cognitive-behavioral therapy,
psychopharmacology, exposure therapy, relaxation training, biofeedback,
meditation, supportive psychotherapy, psychodynamic psychotherapy, and other
forms of psychotherapy (Miller, Fletcher, & Kabat-Zinn, 1995). The most common
treatment strategies these days are cognitive-behavioral therapy and
psychopharmacology. Past research indicates that both genetics and important
events in a person*s life are playing a significant role in the development of
anxiety disorders. However, because there is still a lot unknown about the
aetiology and maintenance of these disorders, more research is needed to
address these issues and to enhance prevention and treatment. Therefore the
current proposal aims to examine important cognitive processes involved in
anxiety and aspires to set up a new approach to a clinical treatment method
targeting these processes.

Over the past three decades cognitive models of anxiety disorders have
demonstrated that selective information processing plays an important role in
the development and maintenance of anxiety (Williams, Watts, MacLeod, &
Mattews, 1988). More specifically, recent studies provide considerable evidence
to state that anxiety is strongly associated with an attentional bias towards
threatening stimuli and biases in interpretation and memory (Mathews & MacLeod,
1994; Mathews & MacLeod, 2005). Patients with an anxiety disorder tend to
interpret ambiguous information in a negative way. Several researches
demonstrate that individuals reporting high levels of anxiety display a
disproportionate ability to identify or detect emotionally negative words (e.g.
Foa & McNally 1986; as described in Mathews & MacLeod, 1994). For example,
during Stroop tasks, anxious individuals display problems ignoring the
emotionally negative content of threat-related stimulus words (e.g. Mathews &
MacLeod 1985; as described in Mathews & MacLeod, 1994). However, the nature of
the relation between anxiety and cognition is far from clear. Therefore, it is
necessary to get more insight in the cognitive processes behind anxiety.

A lot of past research shows that high levels of anxiety are associated with a
reduced ability to perform complex cognitive tasks (Mueller 1992, Watts &
Cooper 1989; as described in Mathews & MacLeod, 1994). A lot of researchers
state that these reductions are being caused by a depletion of capacity-limited
cognitive resources, especially working memory (Eysenck & Calvo 1992, Ellis &
Ashbrook 1988; as described in Mathews & MacLeod, 1994). Therefore, working
memory is an important concept in understanding the cognitive biases associated
with anxiety disorders. Working memory can be described as a limited capacity
system for the temporary, active maintenance and storage of information
(Baddeley, 2003). This system is critical for human thought processes. The
ability to retain and manipulate information in working memory is linked with
the prefrontal cortex (Fuster, 1989; Goldman-Rakic, 1987; as described in
Klingberg, Forssberg, & Westerberg, 2002) and underlies different executive
functions, such as problem solving and reasoning (Engle, Kane, & Tuholski,
1999; Hulme & Roodenrys, 1995; Klingberg, 2000; as described in Klingberg et
al., 2002). The theoretical concept of working memory argues that working
memory is important for human thought processes because it provides an
interface between perception, long-term memory and action (Andrade, 2001;
Miyake & Shah, 1999; Conway, Jarrold, Kane, Miyake, & Towse, 2007; as described
in Klingberg et al., 2002). Reduced working memory capacity is associated with
several neurological and psychiatric disorders like schizophrenia and ADHD
(Goldman-Rakic, 1994; Castellanos & Tannock, 2002; as described in McNab et
al., 2009).

Several researchers showed that working memory can be trained. Klingberg and
colleagues (2002) demonstrated that training of working memory in children and
adults with ADHD (with working memory deficits) significantly enhanced not only
performance on the trained working memory tasks, but also on non-trained tasks
requiring working memory. Their results suggest that working memory can be
significantly improved by training. In 2005 Klingberg and colleagues also found
a significant reduction of ADHD symptoms as a result of the working memory
training. McNab and colleagues (2009) showed that effective training of working
memory is also associated with changes in cortical activity.

These interesting findings lead to an important question for this proposal. Is
it possible to reduce symptoms of anxiety disorders by improving working memory
in patients with these disorders? This proposal aims to study the question
whether an improved working memory will influence overt behaviour and reduce
cognitively related clinical symptoms in patients with anxiety disorders.

The present study is aimed at investigating cognitive underpinnings of anxiety,
by focusing on working memory abilities in anxious individuals. A therapeutic
intervention targeting working memory deficits will be tested in patients with
anxiety disorders, both on a short and longer term. In doing so, this project
ought to yield novel approaches of clinical treatment by targeting cognitive
deficits related to anxiety, in that way bridging the gap between basic
cognitive science and clinical psychological treatments for anxiety disorders.

This study will focus on the outcome of a working memory intervention in a
large sample of individuals with an anxiety disorder. Additionally, it will be
studied whether the outcome effects are resistant to a mood provocation test.

A randomised controlled trial (RCT) will be used in people diagnosed with an
anxiety disorder: 120 individuals will be randomly allocated to either a
working memory training or a bogus working memory training (i.e., simple
arithmetic tasks that do not significantly load working memory ability). All
participants will be recruited from mental health care centres in which they
are waiting for a treatment after having had a diagnostic intake for anxiety.
During an initial session (i.e., Pretest), the researcher (blind to condition)
will use the Structured Clinical Interview for DSM-IV disorders (SCID) to
confirm the diagnosis of an anxiety disorder. Also, the STAI will be used as a
self-report measure for the severity of individuals* anxiety symptomatology.

In the four weeks following this pretest, participants will perform the working
memory intervention three times a week. This intervention will take about half
an hour and is easily accessible via a website that participants can access
from their computer at home. The researcher monitors whether participants have
performed the training and will alert participants in case they have missed a
session. The training will systematically teach individuals to utilize their
working memory on a variety of domains. The tasks will target the specific
working memory abilities that are deficient in anxiety disorders.

After the four-week intervention, the researcher and the participant meet again
(i.e., Posttest). In this posttest, the same measures will be performed as
during the pretest (i.e., SCID, STAI, and appropriate working memory tests). It
is predicted that participants who received the working memory training will
show an increased performance on working memory tests and a decrease in anxiety
symptoms (on the SCID and and the STAI), relative to the pretest and to control
participants.

One of the essential questions is whether this pattern of reduced
symptomatology holds when confronted with stressors. Would the participants
still react with increased working memory performance and reduced anxiety
symptoms when they are temporarily brought into an anxious state? To examine
this issue, an anxious mood provocation (i.e., Velten mood procedure; Velten,
1968) will be used. Indeed, recent research has shown that relapse can best be
predicted by performance on such a mood induction procedure (Segal et al.,
2006). If the working memory training appears to be successful, one would
expect that compared to controls, individuals in the intervention condition are
more resistant to the mood induction and still show increased working memory
performance (hypothesized to be similar as in the posttest), indicating that
relapse is unlikely.

A follow-up test (Follow-up) after two months will be the final step. Assuming
that individuals in the training condition have benefited from the working
memory intervention, one would assume that their anxiety disorder symptoms
(SCID, STAI) would still be lower after such a time interval, relative to
individuals in the control condition. Additionally, one would assume that their
working memory ability is still improved, indicated by a better performance on
the working memory tasks.

Workingmemory tasks at pre- and posttests and at home:
- AB-AC-AD taak
- Number-letter taak

Workingmemory task only at pre- and posttests:
Sternberg taak

Moodinduction

No risks are associated with participation. The benefit is an earlier treatment
and a possible effective treatment.