Shakespeare has long been noted for his insights into acute psychological conditions. Hamlet, Lear, Othello—these and others have been studied for their interesting portrayals of humans caught in stressful situations. This paper extends these studies to two other important characters—Macbeth and Shylock—who, like these others, are particularly interesting when studied in light of the mental challenges they undergo. The paper insists, in fact, that these characters cannot be rightly understood until one recognizes the trauma each faces and the traumatic stress that accompanies it. This stress accounts for much suffering and is reasonable motivation for many of the characters' choices and actions—Macbeth's hallucinations, sleep disturbances, dissociation from Lady Macbeth, and feelings of guilt, depression, and eventual hopelessness and Shylock's insistence on revenge. As a theoretical background, this study describes two types of trauma—individual and collective—then goes on to describe the effects of each type. Macbeth's trauma, it is shown, is of the first type and Shylock's is a combination of the two. The paper argues, finally, that understanding trauma and its effects is the key to understanding Macbeth and Shylock, two often criticized characters who can be seen as more sympathetic when their suffering is better comprehended.