Every war has soldiers that deal with it under different names (shell shock, etc), but it doesn't seem like anyone's really taken it seriously until Iraq/Afghanistan were in full swing. I'm just imagining roman soldiers having to deal with the psychological after effects of the types of battles they were in.
Here are past answers & discussions from the FAQ section Post Tramatic Stress Disorder before the modern era:
Feel free to ask followup questions by commenting with /u/ appended to a flaired specialist's username (i.e. /u/OldWorldGlory).
Key:
M&SC = Methodological & Source Criticism
c = comments
dy = days old
wk = weeks old
mo = months old
yr = years old
[16 c | 7 mo] Flaired Respondents | Middle Ages, Early Modern, M&SC
[15 c | 1 mo] Flaired Respondents | Retroactive Psychological Analysis M&SC
[147 c | 1 yr] Little Analysis | Antiquity, Middle Ages, Early Modern
[55 c | 3 yr] Little Analysis | Rome, Greece, England
[31 c | 1 yr] Detailed Analysis | Roman military
[6 c | 5 mo] Detailed Analysis | Roman military, M&SC
[41 c | 3 yr] Flaired Respondent | Roman & Greek militaries, general pre-modern
[14 c | 2 yr] Detailed Analysis | Roman military, Source Criticism
[83 c | 3 yr] Little Analysis | Knights
[9 c | 6 mo] Flaired Respondent | Clergy
[26 c | 1 yr] Detailed Analysis | Napoleonic France, M&SC
[4 c | 1 yr] Flaired Respondents | Napoleonic France