The only one we know for sure is Sachi Komine.`
Witnessing this event gave Sachi a serious case of Post Traumatic Stress Disorder (PTSD) and Obsessive-compulsive disorder (OCD). She blame herself and believes that she needs to be a good girl to make up for her sins.`
http://grisaia.wikia.com/wiki/Sachi_Komine
It is shown that the other girls have or had a kind or another of mental wound.
Yumiko Sakaki
His son had died, and Yumiko was being spoon fed false kindness to shape her into the next head of the company, Michiaki’s own puppet. This shook Yumiko’s foundation to the core and she was on the verge of a mental breakdown.
http://grisaia.wikia.com/wiki/Yumiko_Sakaki
Amane Suou
The incident leaves Amane with a strong case of survivor's guilt, which is only compounded by media speculation that she survived by engaging in cannibalism. Years later, when Yuuji arrives at Mihama, she recognizes him as Kazuki's brother, and attempts to "atone for her crimes" by helping him in any way she can.
http://grisaia.wikia.com/wiki/Amane_Suou
Michiru Matsushima
After that incident, Michiru gets sent to a mental ward and there she is prescribed a medication to suppress the "other Michiru." A little while later she got released from the mental hospital and enrolls in to Mihama academy as the third student after its establishment.
http://grisaia.wikia.com/wiki/Michiru_Matsushima
Makina Irisu
Makina used to be the successor of Irisu family but her inheritance was transferred to her younger sister, Sarina Irisu , after she suffered a mental shock in an incident.
http://grisaia.wikia.com/wiki/Makina_Irisu
As for Chizuru Tachibana , I didn't find in the wiki or in the anime anything that would indicate the fact that she would have some kind of mental scar.