Summary of the DID Literature

The SCM Reappraised

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Gleaves (1996) concluded by recommending that "the socio-cognitive model be abandoned as an etiological explanation of DID (p. 54). Careful scrutiny of his central arguments, however, reveals that this conclusion is premature and unwarranted. Although Gleaves arrived at strong conclusions regarding the psychopathology of DID, the motivations of DID patients, and the efficacy of extinction treatments for DID, these conclusions appear to be based largely on uncontrolled and, in some cases, anecdotic evidence.

Moreover, several of the central premises of the PTM, such the assumption that the prevalence of child abuse is substantially elevated among DID patients compared with other psychiatric patients, require more compelling data before they can be accepted.

In particular, Gleaves's (1996) conclusion that "there does not appear to be any convincing reason to doubt the association between DID and childhood trauma" (p. 54) is not borne out by careful examination of the evidence. Although a causal link between early abuse and DID cannot be excluded, studies that provide corroborated abuse reports, distinctions between continually recalled and recovered memories of abuse, and psychiatric comparison groups are needed to bring clarity to this methodologically complex area.

In addition, causal modeling studies may help to rule out competing hypotheses for the high levels of co-occurrence between reports of early trauma and later DID an thereby provide more compelling support for the claims of the proponents of the PTM. If such abuse can be corroborated an shown to be correlated with risk for subsequent DID, such studies will be especially informative if they incorporate potential third variables that might account for this correlation, such as adversal early home environment.

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Although the relative paucity of data on the role of iatrogenic factors in DID renders a definitive verdict premature, several lines of evidence converge upon the conclusion that iatrogenesis plays an important, although not exclusive, role in the etiology of DID:

	(a) The number of patients with diagnosed DID has increased dramatically over the past several decades (Elzinga et al., 1998);
	(b) the number of alters per DID case has increased over the same time period (North et al., 1993), although the number of alters at the time of initial diagnosis appears to have remained constant (Ross, Norton, & Wozney, 1989);
	(c) both of these increases coincide with dramatically increased therapist awareness of the diagnostic features of DID (Fahy, 1988);
	(d) a large proportion or majority of DID patients show few or no clear-cut signs of this condition, including multiple identity enactments, prior to therapy (Kluft, 1984);
	(e) mainstream treatment practices for DID patients appear to verbally reinforce patients' displays of multiplicity and often encourage patients to establish further contact with alters (Ross, 1997);
	(f) the number of alters per DID case tends to increase over the course of DID-oriented therapy (Piper, 1997);
	(g) therapists who use hypnosis appear to have more DID patients in their caseloads than do therapists who do not use hypnosis (Powell & Gee, in press);
	(h) the majority of DID diagnoses derive from a relatively small number of therapists (Mai, 1995); and
	(i) laboratory studies demonstrate that nonclinical participants provided with appropriate cues can successfully reproduce many of the overt features of DID (Spanos et al., 1985).

Given the high rates of preexisting mental conditions among DID patients (Spanos, 1996), however, it seems likely that iatrogenic factors do not typically create DID in vacuo but instead operate in many cases on a preexisting substrate of psychopathology, such as BPD.

We believe that each of these nine sources of evidence is fallible and that several (e.g., a, b, f, g, and h) are open to multiple causal interpretations.

For example, the finding that the number of alters per case tends to increase over the course of therapy is potentially consistent with the assertion (Ross, 1997) that therapy for DID is often accompanied by the progressive uncovering of previously latent alters.

Moreover, as Ross (1997) noted, several of these arguments are probably applicable to psychological disorders other than DID; diagnoses of PTSD, for example, have increased dramatically over the past two decades (Zohar, 1998).

Nevertheless, the consilience of evidence across these nine quite diverse sources of data appears to provide an impressive, if not compelling, circumstantial case for the role of iatrogenic factors in DID.

Moreover, Gleaves (1996) acknowledged that iatrogenic factors can produce additional alters, and Ross ( 1997) estimated that approximately 17% of DID cases are predominantly iatrogenic (see also Coons. 1989).

Thus, the principal unresolved question appears to be not whether iatrogenesis sometimes plays a role in either the etiology or maintenance of DID but rather its relative importance compared with other potential causal variables, such as media influences, widely available cultural scripts regarding the expected features of DID, individual differences in personality and psychopathology, and perhaps early trauma. Further research examining the symptomatic characteristics of DID patients before and after treatment is needed to clarify this issue.

Nevertheless, because proponents of the PTM, including Gleaves, have typically contended that the multiple identity enactments of DID patients typically remain hidden prior to treatment, they need to explicate what findings could potentially falsify the assertion (Gleaves, 1996, p. 42) that DID cannot be iatrogenically created.

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