Stress Disorders, Post-Traumatic
Conditions
Keywords
post traumatic stress disorder, cognitive bias, attention, combat, neuroimaging
Brief summary
The purpose of this study is to determine whether a computerized intervention designed to change the nature of attention biases will be effective in reducing the symptoms of post traumatic stress disorder (PTSD) in American combat veterans returning from the wars in Afghanistan and Iraq.
Detailed description
Thirty percent of returning veterans present with mental health problems with Posttraumatic stress disorder (PTSD) as the most common problem in this group (52% of overall diagnoses). This translates into PTSD prevalence rates of 12% in Afghani veterans and 19% for Iraqi veterans, rates that are two to three times higher than the overall lifetime prevalence rate in the general population (8%). Moreover, 70% have not received any mental health services. Thus the majority are not receiving any help. Those with PTSD are likely to experience problems across several life domains including higher rates of divorce, problems raising children, and engaging in domestic violence. They are also more likely to suffer from other mental health problems including depression, substance abuse, and generalized anxiety disorder. Forty four percent of individuals with PTSD do not respond to psychosocial and pharmacological treatments. Thus, there is a clear need to develop highly effective and efficient treatments for PTSD. Researchers have established a relationship between PTSD and difficulty disengaging attention from threat relevant information. This knowledge; however, has not been translated into more effective treatments for this disorder. This five-year proposal aims to test a computerized treatment for PTSD in a double-blind, placebo-controlled study that would bridge research on attention bias and treatment development. Those in the active condition will receive a computer-delivered attention modification program (AMP) designed to enhance attention disengagement from threatening stimuli. The AMP protocol includes six weeks of biweekly sessions in which participants see 240 trials consisting of the various combinations of probe type (E or F), probe position (top or bottom), and word type (Neutral or Trauma). Of the 240 trials, 48 include only neutral words: 2 (probe type) X 2 (probe position) X 12 (word pairs). The remaining 192 trials include one neutral word and one trauma word: 2 (probe type) X 2 (probe position) X 2 (repetitions) X 24 (word pairs). On trials where participants see one neutral word and one trauma word (i.e., 80% of the trials), the probe always follows the neutral word. Thus, although there is no specific instruction to direct attention away from threat word, on 80% of the trials the position of the threat word indicates the position of the probe (i.e., in the location opposite the threat word). The placebo condition (PC) will be identical to the AMP condition except that during the presentation of threat/neutral word pairs, the probe will appear with equal frequency in the position of threat and neutral words. Thus, neither threat nor neutral words have signal value. We have used this intervention to successfully establish a pattern of enhanced attention disengagement to threat words in 3 studies. We present the results from 3 clinical trials demonstrating the efficacy of attention modification programs (AMP) in ameliorating symptoms of anxiety. Specifically, we report results from studies of individuals with generalized social phobia (GSP; n=53) and generalized anxiety disorder (GAD; n=24) demonstrating the effectiveness of the procedures described in this proposal. In brief, our intervention was effective in: a) changing biased attention, b) reducing clinical symptoms of anxiety, c) maintaining its effects in up to one year follow-up. This efficient and efficacious technique for changing attention bias in anxiety can provide a low cost, easy to administer treatment that is grounded in basic cognitive science that may help reduce suffering in individuals with anxiety. The goal of the current proposal is to extend these findings to the highly related disorder of PTSD, and to examine the generalizability of the results to individuals with comorbid conditions. In the current proposal we will test two hypotheses: 1) Individuals with PTSD completing the AMP will show a larger reduction in their attention bias to threat compared to the placebo group, 2) Individuals with PTSD completing AMP will show a larger reduction in anxiety symptoms compared to the placebo group.
Interventions
BEHAVIORALAttention Bias Modification (ABM)
The ABM comprised a probe detection paradigm described above, modified to facilitate the allocation of attention away from threatening material. In this task, the probe always replaced the neutral word. Stimuli comprised a different set of 12 threat-neutral word pairs different than those used in the attention bias assessment. Participants completed 288 training trials: 2 (probe type) x 2 (probe location) x 2 (threat location) x 12 (threat-neutral word pairs) x 3 (repetition). Thus, although there were no explicit instructions to direct attention away from threat words, on all trials, the position of the neutral word indicated the position of the probe.
BEHAVIORALAttention Control Condition (ACC)
The ACC condition was identical to the ABM procedure with the exception that the probe appeared with equal frequency in the position of the threat and neutral words, such that attention was neither trained towards nor away from threat.
Sponsors
San Diego State University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Primary DSM-IV-TR Axis I diagnosis of post-traumatic stress disorder * Combat veteran from Iraq and/or Afghanistan
Exclusion criteria
* No change in medication type or dose during the twelve weeks prior to treatment * No current psychotherapy * No evidence of suicidal intent * No evidence of current substance dependence in the past 6 months * No evidence of current or past schizophrenia, bipolar disorder, or organic mental disorder
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Post-Traumatic Stress Disorder Checklist-Military Version (PCL-M) | Pre-Treatment, Post-Treatment (after 4 weeks of treatment) | The PCL-5 is a 20-item self-report measure that assesses the 20 DSM-5 symptoms of PTSD. Scores range from 0 to 80, with higher scores indicating more severe symptoms. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| 1 Attention Bias Modification (ABM) The ABM comprised a probe detection paradigm described above, modified to facilitate the allocation of attention away from threatening material. In this task, the probe always replaced the neutral word. Stimuli comprised a different set of 12 threat-neutral word pairs different than those used in the attention bias assessment. Participants completed 288 training trials: 2 (probe type) x 2 (probe location) x 2 (threat location) x 12 (threat-neutral word pairs) x 3 (repetition). Thus, although there were no explicit instructions to direct attention away from threat words, on all trials, the position of the neutral word indicated the position of the probe. | 15 |
| 2 Attention Control Condition (ACC) The ACC condition was identical to the ABM procedure with the exception that the probe appeared with equal frequency in the position of the threat and neutral words, such that attention was neither trained towards nor away from threat. | 10 |
| Total | 25 |
Baseline characteristics
| Characteristic | 1 Attention Bias Modification (ABM) | 2 Attention Control Condition (ACC) | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 15 Participants | 10 Participants | 25 Participants |
| Region of Enrollment United States | 15 participants | 10 participants | 25 participants |
| Sex: Female, Male Female | 1 Participants | 1 Participants | 2 Participants |
| Sex: Female, Male Male | 14 Participants | 9 Participants | 23 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 15 | 0 / 10 |
| serious Total, serious adverse events | 0 / 15 | 0 / 10 |
Outcome results
Primary
Post-Traumatic Stress Disorder Checklist-Military Version (PCL-M)
The PCL-5 is a 20-item self-report measure that assesses the 20 DSM-5 symptoms of PTSD. Scores range from 0 to 80, with higher scores indicating more severe symptoms.
Time frame: Pre-Treatment, Post-Treatment (after 4 weeks of treatment)
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| 1 Attention Bias Modification (ABM) | Post-Traumatic Stress Disorder Checklist-Military Version (PCL-M) | Pre-Treatment | 63.08 units on a scale | Standard Deviation 9.13 |
| 1 Attention Bias Modification (ABM) | Post-Traumatic Stress Disorder Checklist-Military Version (PCL-M) | Post-Treatment (after 4 weeks of treatment) | 42.83 units on a scale | Standard Deviation 12.04 |
| 2 Attention Control Condition (ACC) | Post-Traumatic Stress Disorder Checklist-Military Version (PCL-M) | Pre-Treatment | 61.71 units on a scale | Standard Deviation 9.04 |
| 2 Attention Control Condition (ACC) | Post-Traumatic Stress Disorder Checklist-Military Version (PCL-M) | Post-Treatment (after 4 weeks of treatment) | 51.65 units on a scale | Standard Deviation 14.72 |