Sandy was seen at the mental health clinic because, since her return from active duty, she has been experiencing flashbacks, nightmares, and insomnia and reports feeling "depressed all the time." She is prescribed antidepressants. In light of her diagnoses of PTSD and depression, which of these medications should most likely be the first line of treatment?
1) Haloperidol
2) Escitalopram
3) Diazepam
4) Lithium carbonate