The foregoing review has suggested that individuals with depression and PTSD retrieve overgeneral memories when attempting to retrieve memories of specific events. This phenomenon is a reliable feature of these diagnostic groups and can be found in other (though not all) emotional disorders. The phenomenon of overgeneral memory ranks alongside other memory deficits known for many years to be associated with depression but goes beyond these in several ways.
First, overgeneral memory is a hitherto unrecognized consequence of trauma and adversity, even in the absence of depression. The significance of this is that negative experiences or trauma in the past can have effects on the retrieval of events that have nothing to do with the trauma itself, owing to a general tendency to truncate memory search. We have seen that these effects can be reversed given certain retrieval conditions and therefore cannot be explained in terms of permanent damage to the processes underlying encoding. Given that generic retrieval is a normal part of development, and its retention as one possible mode of retrieval is required as part of normal memory function (e.g., as an intermediate stage in the recollection of specific episodes and as the target of retrieval for scriptlike situations), it is more likely that individuals discover that overgeneral memory is adaptive in gating out unwanted affect. Such functional avoidance is central to understanding the mechanisms underlying overgenerality in memory.
Second, however, we have seen that a functional avoidance theory is not sufficient to explain all of the data. We have suggested that the memory impairment may also result from capture and rumination. Overgeneral memory can be seen as a type of capture error arising because of the activation, by the intermediate descriptions that are required for voluntary retrieval, of task-irrelevant material in the self-memory system. Patients with depression and PTSD are particularly vulnerable to this interruption of on-task processing owing to a combination of the presence of salient (and more distracting) self-referent information, on the one hand, and a tendency to ruminate, on the other.
Third, each of these two factors, avoidance and capture/rumination, interacts with impairment in a third major mechanism underlying memory retrieval: executive control. Reduced executive control results in a failure to inhibit competing information. The result is a greater likelihood of retrieval being “hijacked” by task-irrelevant material.
Fourth, in whomever it is found, overgeneral memory is associated with, and has been found in some cases to have a direct causal relation to, important “downstream” consequences. The research shows that overgeneral memory is an important factor in affecting a person's problem-solving ability and his or her ability to generate specific images of the future. It predicts the course of emotional disorders, being associated with poorer outcome in depression, PTSD, and a number of other conditions. But it affects not only how effectively people cope with serious emotional disturbance but also how they regulate their emotions in the face of more normal life events, such as the birth of a child (Mackinger, Loschin, & Leibetseder, 2000
We have seen that there are a number of methodological issues that limit the conclusions that can be made from many of the studies taken individually. But across the studies as a whole, a consistent picture emerges: that the way one remembers one's past is as important as what is remembered; that the specificity of memory can be affected by and can affect a number of psychological variables; that it is part of the causal sequence in facilitating or impairing important aspects of psychological functioning such as problem solving and one's ability to imagine the future; that it can be modified by treatment; and that, when it is modified, it reduces depression and hopelessness.