From the New York Times, And Still, Echoes of a Death Long Past:

All deaths leave their mark. But studies suggest that the psychological legacy of a suicide may differ from that of other deaths.

“Suicide flies in the face of people’s beliefs abut how life is and how it operates,” said Dr. John Jordan, the author of a 2001 review of research on suicide survivors and the director of the Family Loss Project, a group based near Boston that conducts research and offers treatment to the bereaved.

“Survivors spend a great deal of time trying to figure things out,” Dr. Jordan said. “What was the person’s frame of mind? How could they have done this? Who is responsible for it? What does it mean?”

Some people pass through a normal grief process and heal quickly.

But studies suggest that suicide survivors often experience more guilt, rejection, shame and isolation than those who grieve other deaths. If they have spent years dealing with a relative bent on an escalating course of self-destruction, they may also feel relief.

Some studies have found that family members bereaved by suicide feel worse about themselves and are viewed more negatively by others. In a 1993 study, wives who had lost their husbands to suicide were seen as more psychologically disturbed, less likable and more blameworthy than wives whose husbands had died from heart attacks or in accidents.

Suicide survivors themselves have an elevated risk of suicide, and according to some studies are more vulnerable to depression, a risk factor for suicide. In a 1996 study, Dr. Brent and his colleagues found higher levels of depression in the siblings of adolescent suicide victims six months after the death, and in the mothers of the victims one year afterward, compared with a control group. At three years, the siblings were no more depressed than a control group, but the mothers were still having difficulty.

The issue of accountability, Dr. Jordan said, of who is to be held responsible for the death, often gnaws at suicide survivors.