Today the prosecution concluded and rested in its death penalty case against Casey Anthony. Tomorrow it's the defense team's turn. So far--other than hinting at Casey's proficient capacity to hide her feelings (perhaps even from herself) stemming from a supposed incestual relationship with her father--no claims to the presence of any mental disorder and no forensic psychological or psychiatric testimony has been presented by either side. That may all change now. Depending upon how well or poorly they perceive their case to be progressing, Ms. Anthony's defense team may have to turn to forensic psychology and psychiatry for support. But how could expert testimony by forensic psychologists or psychiatrists meaningfully contribute to this sensational murder trial? Especially when the defense has not entered a plea of Not Guilty by Reason of Insanity?

One of the things juries--and the rest of us--instinctively seek is some way of making sense of evil deeds like the one Casey Anthony stands accused of having committed. Forensic psychology and psychiatry can offer explanations--if not necessarily excuses--for destructive or evil behavior. And these explanations, both psychological and sometimes neurological or medical, provide jurors with something much more powerful than the "objective" circumstantial facts and items submitted to them so far as hard evidence of Ms. Anthony's guilt. Forensic psychology and psychiatry can help disclose the human frailties, pathologies, selfishness, rage and tragic circumstances that motivate or drive defendants to commit evil deeds, providing perplexed jurors and observers with ways of understanding not just what the physical evidence suggests, but why we humans behave badly. And that--no matter how charming, innocent, attractive or charismatic the persona or inconclusive the evidence--they sometimes can and do.

What might forensic psychology or psychiatry potentially bring to the table regarding Casey Anthony's strange behavior? How might the introduction of forensic evaluation and testimony hypothetically play out in such a high stakes life and death case? Here is one possible (albeit highly improbable) scenario.

In my prior postings on this case, I mentioned both denial and the defense mechanism Sigmund Freud referred to as dissociation. Dissociation is a form of repression: It involves disconnecting from impulses, sensations, thoughts, experiences, feelings or memories that are too painful, traumatic or considered incompatible with the individual's conscious personality. One of the most dramatic manifestations of such dissociative defense mechanisms is known today as Dissociative Identity Disorder, formerly called Multiple Personality Disorder. There is a great deal of professional disagreement surrounding the legitimacy of this disorder, the appropriate application of the diagnosis, and its true etiology. Though once believed to be exceedingly rare, in recent decades the reported incidence of DID in the United States has been rising, as have other dissociative disorders. Classic cases of DID (or MPD) have been depicted in popular books and films like The Three Faces of Eve, Sybil, and When Rabbit Howls. Of course, DID can lend itself to malingering (faking) by defendants seeking to evade responsibility for their crimes. For instance, "Hillside Strangler" Kenneth Bianchi attempted, unsuccessfully, to feign multiple personality disorder during his own serial murder trial.

According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Dissociative Identity Disorder (or MPD) involves "the presence of two or more distinct identities or personality states (each with its own relatively enduring pattern of perceiving, relating to and thinking about the environment and self.) At least two of these identities or personality states recurrently take control of the person's behavior." And, "each personality state may be experienced as if it has a distinct personal history, self-image, and identity, including a separate name." Or, to put it somewhat more graphically, these so-called "subpersonalities" (they can number from two to more than one hundred!) actually take possession of the afflicted person's thoughts and actions. "The personality that presents itself for treatment often has little or no knowledge of the existence of the other personalities. . . . Studies have demonstrated that various personalities in the same person may have different physiologic characteristics and different responses to psychological psychological tests. Different personalities may, for example, have different eyeglass prescriptions, different responses to the same medication, and different I.Q.'s." Quite a remarkable phenomenon, and one which few clinicians ever come across. Amnesia or an inability to recall what the so-called "alter" personality said or did during their period of temporary domination is also common. According to DSM-IV-TR, " Dissociative Identity Disorder is diagnosed three to nine times more frequently in adult females than in adult males."

From the perspective of depth psychology, DID may be the most convincing demonstration of Jung's notion of the relative "autonomy" of unconscious complexes. Elaborating on the early discoveries of Freud and Breuer, C.G. Jung postulated that complexes "are psychic fragments which have split off owing to traumatic influences of certain incompatible tendencies." Jung spoke of the complexes as behaving like "secondary or partial personalities possessing a mental life of their own." When chronically repressed or dissociated, these "splinter personalities" can become sufficiently powerful to usurp the entire personality, causing a temporary condition of acute possession. In DID, the personality is compartmentalized into walled-off sub-personalities (complexes), each containing encapsulated unconscious contents too traumatic, painful or morally unacceptable for the person to consciously acknowledge. Robert Louis Stevenson's story The Strange Case of Dr. Jekyll and Mr. Hyde is an archetypal tale of possession by an unconscious "alter ego" or complex. Or what Jung famously referred to as the shadow.

Considering DID as one of many possible psychiatric diagnoses could hypothetically make Ms. Anthony's bizarre behavior, both prior, during and subsequent to her arrest, more comprehensible for mystified members of the jury. For example, what if so-called "Zanny the nanny" in actuality turned out to be one of Casey's own shadowy subpersonalities or "alters"? Casey claims that this "Zanny" character physically restrained her and forcefully took her daughter, Caylee, from her. When asked whether she gave any reason for this treatment, Casey's brother Lee, during his testimony, stated that he was told by Casey that "Zanny" accused her of being a bad mother, and was "punishing" Casey for this by kidnapping her child to "teach her a lesson."  Could "Zanny" in this case be nothing more than an imaginary manifestation of Casey's own "superego," her guilt, anger and introjection of her mother's harsh criticisms regarding her parenting of Caylee? Casey further allegedly told Lee that "Zanny" then tormented her, directing her to go to various destinations via internet and text messages, threatening family members, and had somehow acquired the password for Casey's account, changing it to "timer 55."

Was this in reality some sort of dissociated interior dialogue going on within Ms. Anthony's mixed up mind? And, could it have been Casey Anthony's evil "Ms. Hyde" who hatefully killed Caylee in order to spite her mother and be free to indulge her frustrated hedonistic appetites and impulses? And who then celebrated brazenly and euphorically her newly found freedom after committing the evil deed? If Ms. Anthony in fact did murder her daughter Caylee as charged, was it this dissociated part of her personality that did so when in total or partial control of Casey's psyche? If so, it would be theoretically possible that Casey's primary, conscious personality or persona, truly has no knowledge or recollection of what really happened when under "Hyde's" evil influence. Could this massive dissociation be what makes Ms. Anthony appear to be such an excellent liar? Moreover, DID patients frequently have a confirmed history of severe physical and/or sexual abuse during childhood, something Casey and her defense team have now alleged in open court.

While this may all sound extremely far-fetched, especially in this (and, to most jurors, in any) case, hopefully readers can see how a legitimate diagnosis like Dissociative Identity Disorder or some other, less exotic major mental disorder could, when properly arrived at and explained by competent forensic clinicians, be used to defend someone like Ms. Anthony and to elicit some compassion from jurors. I do not know this defendant's psychiatric diagnosis (if there is one) and have never evaluated her. As mentioned by me previously, Bipolar Disorder could be another possibility in cases such as this. As might what I've called "psychopathic narcissism." (See my prior post on Joran van der Sloot.) Or Borderline Personality Disorder, from which Susan Smith supposedly suffered. However, it seems that being assigned (as so many pundits have already questionably concluded) a diagnosis of Antisocial Personality Disorder (sociopathy or psychopathy) could, if clinically warranted, on the other hand, conceivably work against the defense and favor the prosecution. Finally, having the presence of any serious mental disorder ruled out or eliminated by forensic evaluators obviously can strengthen the case for the State. In either event, it seems to me that some expert psychological testimony in this trial is called for--either during the upcoming defense or, if Casey is convicted, during the penalty phase--if for no other reason than to help the family, public, judge and especially jurors make sense of how, whether and why a young mother like Casey Anthony could commit this alleged evil deed and what consequences she should suffer.