2. Authors contacted.
| Study ID | Name of contact author | Response from author |
| Asadabadi 2013 | S. Akhonzadeh | No response |
| Belsito 2001 | K. Belsito | No response |
| Chugani 2016 | D. Chugani | No response |
| Ghaleiha 2013a | S. Akhonzadeh | No response |
| Ghaleiha 2015 | S. Akhonzadeh | No response |
| Ghaleiha 2016 | S. Akhonzadeh | No response |
| Handen 2000 | B. Handen | No response |
| Handen 2005 | B. Handen | No response |
| Handen 2008 | B. Handen | No response |
| Handen 2011 | B. Handen | No response |
| Mohammadi 2013 | S. Akhonzadeh | No response |
| Nikoo 2015 | S. Akhonzadeh | No response |
| Hollander 2012 | E. AnagNostou | No response |
| E. Hollander | No response | |
| Kern 2001a | J. Kern | No response |
| Kern 2002 | J. Kern | No response |
| King 2001 | B. King | No response |
| Mace 2001 | N. Blum | No response |
| McDougle 1996 | C. McDougle | Email bounced |
| Miral 2008 | S. Miral | No response |
| Molloy 2002 | C. Molloy | No response |
| Mouti 2014 | M. O'Sullivan | No response |
| A. Mouti | Received response but referred to another author | |
| D. Reddinhough | Was provided with a full‐text paper containing the additional data | |
| Munesue 2016 | T. Munesue | No response |
| Novotny 2004 | E. Hollander | No response |
| Remington 2001 | G. Remington | No response |
| Rezaei 2010 | S. Akhonzadeh | No response |
| Sandler 1999 | AD. Sandler | No response |
| Wasserman 2006 | S. Wasserman | No response |
| Wasserman 2006 | E. AnagNostou | No response |