Table 1. Characteristics of association studies eligible for inclusion in Meta-Analysis of 5-HTTLPR polymorphisms and Post-traumatic Stress Disorder (PTSD).
| First author | Year | Study design | PTSD N | Controls N | Total sample (N) | Males N (%) | MeanAge | Diagnostic instrument | PTSD assessed | Biallelic/ Triallelic Genotype | GxE study | Interaction description | Remarks | |
| Lee [18] | 2005 | Case-Control | 100 | 197 | 297 | 119 (40.1) | 34.94 | SCID-I Korean Version | Current | Biallelic | No | - | Included | |
| Koenen [16] | 2009 | Cross-Sectional | 19 | 571 | 590 | 215 (36.4) | 65.1 | National Women's Study PTSD Module | Last 6 months | Triallelic | Yes | High crime & High unemployment rate | Included | |
| Mellman [21] | 2009 | Case-Control | 55 | 63 | 118 | 40 (33.9) | 39.97 | CAPS | Lifetime | Triallelic | No | - | Included | |
| Xie [20] | 2009 | Cross-Sectional | 229 | 1023 | 1252 | 656 (52.4) | 38.97 | SSADDA | Lifetime | Triallelic | Yes | Childhood adversity & Adult traumatic events | Included | |
| Grabe [19] | 2009 | Cross-Sectional | 67 | 1596 | 1663 | 857 (51.5) | 57.61 | PTSD Module of SCID | Lifetime | Triallelic | Yes | Frequent Trauma event | Included | |
| Thakur [47] | 2009 | Cohort study | 24 | 17 | 41 | 19 (46.3) | 31.96 | CAPS | Last year | Biallelic | No | – | Included | |
| King [52] | 2009 | Cohort study | – | – | 378 | – | – | Computer-aided telephone interviews. | Lifetime | Triallelic | Yes | Childhood adversity | Not included | |
| Kolassa [17] | 2010 | Cross-Sectional | 331 | 77 | 408 | 218 (53.4) | 34.72 | Post-traumatic Diagnostic Scale | Lifetime | Biallelic | Yes | Number of traumatic events experienced | Included | |
| Handwerger [53] | 2010 | Case-Control | 18 | 18 | 36 | – | – | – | – | – | No | – | Not included | |
| Saying [48] | 2010 | Cohort study | 29 | 48 | 77 | 47 (61) | – | CAPS | Lifetime | Biallelic | No | – | Included | |
| Koenen [50] | 2011 | Cross-Sectional | 23 | 77 | 100 | 40 (40) | 45.32 | Modified PTSD Checklist | Lifetime | Triallelic | Yes | Number of traumatic events | Included | |
| Morey [49] | 2011 | Case-Control | 22 | 20 | 42 | 22 (52.4) | 34.04 | DTS. Cutoff score = 32 | Current | Triallelic | No | – | Included | |
| Valente [46] | 2011 | Case-Control | 65 | 34 | 99 | 28 (28.3) | 39.99 | SCID-I & CAPS | Current | Biallelic | No | – | Included | |
| Wang [45] | 2011 | Case-Control | 212 | 176 | 388 | 200 (51.55) | 49.06 | SCID-I, MINI, CES y CAPS | Current | Triallelic | No | – | Included | |
| King [44] | 2011 | Case-Control | 16 | 14 | 30 | – | – | – | – | Biallelic | No | – | Not included | |
| Xie [51] | 2012 | Cross- Sectional | AA | 321 | 2078 | 2399 | 1343 (56) | 42.2 | SSADDA | Lifetime | Biallelic | Yes | Childhood adversity | Included |
| EA | 398 | 2381 | 2779 | 1559 (56.1) | 39 |
GxE study: Gene-Environmental interaction study; SCID-1: Structured Clincal Interview for DSM-IV; CAPS: Clinical Assessed PTSD Scale; SSADDA: Semi-Structured Assessment for Drug Dependence and Alcoholism; MINI: Mini-International Neuropsychiatric Interview; CES: Combat Exposure Scale; DTS: Davidson Trauma Scale; AA: Afro-Americans; EA: Euro-Americans.