Anxiety disorders are highly prevalent; they are the most frequent psychological disorders (Kessler et al., 2005) and are often chronic and disabling (Baxter et al., 2014).

Those who experience anxiety often do not experience symptoms on a daily basis and symptoms may be unpredictable (Alpers, 2009). Alternatively anxiety symptoms can occur in specific situations, which are difficult to replicate. Therefore the accurate recording of symptoms to inform research, assessment and treatment as current retrospective self reports may be prone to bias (Ebner-Priemer & Trull, 2012).

This narrative review evaluated the extent to which Experience Sampling Methods (ESM) and Ecological Momentary Assessment (EMA) had been applied to the study of anxiety disorders.

Methods

• The authors searched two online databases (Medline and PsychINFO) and by searching the bibliographies of included studies
• Studies were included if they used self-completed assessments outside a laboratory setting
• Studies prior to the publication of DSM-IV (1994) were excluded
• Studies were also excluded if they lasted less than 24 hours
• Dissertations were excluded

Results

Study characteristics

• 34 studies were included in the review
• 29 studies evaluated adult populations and 5 evaluated children and adolescents
• The included studies evaluated ESM/EMA in:
  • Panic Disorder (n=11)
  • Post traumatic stress disorder (n=9)
  • Social phobia (n=6)
  • Generalised anxiety disorder (n=4)
  • Obsessive compulsive disorder (n=2)
• Studies used a variety of methods to record observations:
  • Paper (n=10)
  • PDAs (Personal digital assistants) (n= 20)
  • Phones (n=4)
• Number of observations per day range from 1 to 16

Main findings of ESM/EMA

Panic disorder

• Patients may be less accurate in perceiving bodily anxiety symptoms than controls
• Treatment reduces anxiety but over estimation of panic attack remains and may lead to risk of relapse

Generalised anxiety disorder (GAD)

• GAD patients perceive bodily changes less accurately than controls
• PDAs may support collection of data and therapeutic support
• Changes in symptoms during treatment may be a good predictor of treatment outcome

Post traumatic stress disorder (PTSD)

• Patients experience symptoms longer than panic disorder patients
• Patients may smoke to suppress negative affective states
• Symptoms may be associated with acute neuroendocrine alterations

Social phobia

• Patients may have problems differentiating negative but not positive emotions
• ESM/ESA may be used to monitor changes in peak anxiety in treatment

Obsessive compulsive disorder (OCD)

• Patients over-estimated associations between symptoms and variables such as stress

Anxiety disorder in youth

• Studies showed potential usefulness in elucidating sources of stress
• ESM/ESA baselines were predictors of treatment outcomes

Conclusions

The authors concluded:

ESM/ESA added significantly to the understanding of anxiety disorders and their treatment, beyond the insight gained from conventional measures.

ESA/ESM assisted in understanding the bi-directional relationship of anxiety and its fluctuation within an individual.

• ESA/ESM could be successfully applied to psychological treatments and ESA/ESM data was superior to baseline affective states assessed with self-report measures in predicting treatment outcomes
• Both time and event contingent recording are suitable in recording phenomena that fluctuate over time
• ESA/ESM can be used effectively by clinicians to track an individual through treatment and may allow therapists to tailor interventions to current symptomology and can support in enhancing approach behaviours. It can also provide real time feedback to individualise treatment

Strengths

The review had some strengths:

• The review did not limit its scope to a specific disorder and focused on studies that would more closely resemble clinical practice (rather than laboratory experiments) and which are arguably more generalisable across anxiety disorders
• Additionally the researchers provided clear details of the search strategy used, which could allow other researchers to replicate and build on the review

Limitations

The review also had several limitations:

• The search was limited to two databases and only included DSM-IV criteria, which may have limited the amount of studies identified
• The study also included a variety of ESA/ESM methods; as a result it is difficult to determine which method of recording or contingency is the most reliable or effective in capturing anxiety symptoms
• There was no comment on the relative effectiveness of each recording method (paper, PDA, phone), which may have been useful to explore and aid in the consideration of how this method could be applied in routine clinical practice
• The reviewers also did not consider or account for publication bias in the review; as a result it is unclear if the included studies are representative of the academic literature
• The study did not consider the risk of bias or study quality within the review; therefore little can be determined about the robustness of the research methodology, which limit the conclusions that can be drawn

Summary

The systematic review assessed the use and utility of ESA/ESM in the recording of anxiety symptoms in a range of anxiety disorders. The narrative review concluded that ESA/ESM was more accurate in capturing anxiety related phenomena than traditional self-report measures. ESA/ESM also at baseline was superior to self-report measures in predicting treatment outcomes.

However, the review did not assess the level of publication bias or the relative methodological quality of the studies so it is unclear how generalisable or reliable the conclusions are, as there is the possibility of bias within the review.

Also it is unclear which ESA/ESM method is the most accurate and if the accuracy rates vary between disorders and this limits the generalisability for clinical practice.

Overall this review raises an interesting question of how to record fluctuating phenomena and a possible use of technology in collecting clinical data. However, it seems that this review raises more questions than it answers and highlights the relative paucity of high quality research evidence across the anxiety disorders.

Links

Primary paper

Waltz LC, Nauta MH, aan het Rot M. (2014) Experience sampling and ecological momentary assessment for studying the daily lives of patients with anxiety disorders: A systematic review. Journal of Anxiety Disorders 28, 925-937. [PubMed abstract]

Other references

Alpers GW. (2009). Ambulatory assessment in panic disorder and specific phobia. Psychological Assessment, 21(4), 476-485. [PubMed abstract]

Baxter AJ, Vos T, Scott KM, Ferrai AJ, Whiteford HA. (2014) The global burden of anxiety disorders in 2010. Psychological Medicine, 22, 1-12. [PubMed abstract]

Conner TS. (2015) Experience sampling and ecological momentary assessment with mobile phones (PDF).

Ebner-Priemer UW, Trulli TJ. (2012) Investigating temporal instability in psychological variables. In M.R. Mehl & T.S. Conner (Eds.) Handbook of research methods for studying daily life. Guildford: New York, NY. [Table of contents PDF]

Kessler RC, Berglund P, Demier O, Jin R, Merikangas KR, Walters EE. (2005) Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbity Survey Replication (PDF). Archives of General Psychiatry, 62 (6), 593-602.