TABLE 1.
Summary of the Included Studies for the Meta-Analysis of Functional Neuroimaging Studies in PTSD, Social Anxiety Disorder, and Specific Phobiaa
| Disorder | Reference | Comparison Subjects | Patients | Emotional Stimulation | Included Contrasts | Symptom Provocation? | Method |
|---|---|---|---|---|---|---|---|
| Posttraumatic stress disorder (PTSD) | Bremner et al. (1999) (23) | 12 | 10 | Neutral and traumatic scripts | Trauma-neutral | Yes | Positron emission tomography (PET) |
| PTSD | Bremner et al. (1999) (24) | 10 | 10 | Neutral and traumatic sounds/pictures | Trauma-neutral | Yes | PET |
| PTSD | Bremner et al. (2004) (25) | 9 | 12 | Color naming color and emotional words | Emotional-neutral | No | PET |
| PTSD | Bremner et al. (2003) (26) | 11 | 10 | Neutral and emotional words | Deep emotional-neutral | No | PET |
| PTSD | Britton et al. (2005) (21) | 14 | 16 | Neutral and traumatic scripts | Trauma-neutral | Yes | PET |
| PTSD | Lanius et al. (2002) (27) | 10 | 7 | Traumatic script | Trauma-baseline | Yes | Functional magnetic resonance imaging (fMRI) |
| PTSD | Lanius et al. (2001) (28) | 9 | 9 | Traumatic script | Trauma-baseline | Yes | fMRI |
| PTSD | Lanius et al. (2003) (29) | 10 | 10 | Neutral and emotional scripts | Emotional-baseline for 1) traumatic, 2) sad, 3) anxious | Yes (only trauma) | fMRI |
| PTSD | Phan et al. (2006) (22) | 15 | 16 | Negative and neutral pictures | Negative-neutral (controls are combat) | No | PET |
| PTSD | Sakamoto et al. (2005) (30) | 16 | 16 | Masked traumatic and neutral images | Masked trauma-masked neutral | Yes | fMRI |
| PTSD | Shin et al. (1999) (31) | 8 | 8 | Neutral and traumatic scripts | Trauma-neutral | Yes | PET |
| PTSD | Shin et al. (2004) (6) | 19 | 17 | Neutral and traumatic scripts | Trauma-neutral for 1) male combat, 2) female nurse veterans | Yes | PET |
| PTSD | Shin et al. (2005) (7) | 13 | 13 | Fearful and happy faces | Fearful-happy | No | fMRI |
| PTSD | Williams et al. (2006) (8) | 13 | 13 | Fearful and neutral faces | Fearful-neutral | No | fMRI |
| PTSD | Yang et al. (2004) (32) | 6 | 5 | Neutral and traumatic images | Earthquake-neutral for 1) perception, 2) imagery | Yes | fMRI |
| Social anxiety disorder | Amir et al. (2005) (44) | 11 | 11 | Disgust and neutral faces | Disgust-neutral | Yes | fMRI |
| Social anxiety disorder | Kilts et al. (2006) (45) | 6 | 12 | Social anxiety and neutral imagery scripts | Social anxiety disorder-neutral script | Yes | PET |
| Social anxiety disorder | Lorberbaum et al. (2004) (9) | 6 | 8 | Speech anticipation | Anticipation-rest | Yes | fMRI |
| Social anxiety disorder | Phan et al. (2006) (10) | 10 | 10 | Harsh and happy faces | Harsh-happy | Yes | fMRI |
| Social anxiety disorder | Stein et al. (2002) (11) | 15 | 15 | Negative and happy faces | Negative-happy | Yes | fMRI |
| Social anxiety disorder | Straube et al. (2004) (12) | 10 | 10 | Angry and neutral faces | Angry-neutral for 1) implicit task, 2) explicit task | Yes | fMRI |
| Social anxiety disorder | Straube et al. (2005) (13) | 9 | 9 | Angry, happy, and neutral faces | Main effect for 1) angry, 2) happy, 3) neutral | Yes | fMRI |
| Social anxiety disorder | Tillfors et al. (2001) (14) | 6 | 18 | Public and private speaking | Public-private speaking | Yes | fMRI |
| Specific phobia | Dilger et al. (2003) (15) | 10 | 10 | Spider pictures | Spider pictures-baseline | Yes | fMRI |
| Specific phobia | Schienle et al. (2005) (16) | 13 | 10 | Phobia, fear, disgust, and neutral pictures | 1) Phobia-neutral, 2) fear-neutral, 3) disgust-neutral | Yes (only phobia) | fMRI |
| Specific phobia | Straube et al. (2006) (36) | 14 | 28 | Spider and control videos | Spider-control | Yes | fMRI |
| Specific phobia | Straube et al. (2004) (33) | 11 | 11 | Phobia and control words | Phobia-control | Yes | fMRI |
| Specific phobia | Straube et al. (2006) (17) | 12 | 11 | Spider and mushroom pictures | Spiders-mushrooms for 1) identification, 2) distraction tasks | Yes | fMRI |
| Specific phobia | Veltman et al. (2004) (18) | 6 | 12 | Spider and butterfly pictures | Spiders-butterflies | Yes | PET |
| Specific phobia | Wright et al. (2003) (34) | 10 | 10 | Fearful, neutral, and happy faces | Fearful-neutral | No | fMRI |
Sample sizes, emotional stimulation paradigm used, included comparisons, and whether the study was a symptom-provocation study are noted. Overall, we analyzed data from 19 comparisons (see Methods) in PTSD, 11 in social anxiety disorder, and 10 in specific phobia, which together involved 172 patients with PTSD, 93 with social anxiety disorder, and 92 with specific phobia and 314 comparison subjects (175 for PTSD, 73 for social anxiety disorder, and 76 for specific phobia). Reference numbers are in parentheses. The sample size-weighted average age of the patient and comparison cohorts in the PTSD studies (mean=42.3, SD=17.5) was not significantly different from that in the social anxiety disorder studies (mean=30.4, SD=11.8; p=0.10 by t test). The PTSD cohorts, however, were older than the specific phobia cohorts (mean=24.7, SD=2.4; p=0.001), which did not significantly differ from the social anxiety disorder cohorts (p=0.27). The proportion of female subjects in the PTSD studies (50.3%) did not differ from the proportion in the social anxiety disorder studies (54.2%), which were both significantly different from the specific phobia studies, which were made up predominantly of women (93.5%; both p<0.0001 by chi-square tests).