Automobile Brain Trauma or Schizophrenia?
PET Scan Use in Distinguishing These Two Options
There are two issues related to the meaning of X's PET scan. First, what are the findings in Schizophrenia PET Scan studies to date, and what are not the typical findings. First, while it is expensive to have a PET Scan done at all, certain patterns are emerging that are consistent with other research on the areas of damage involved with Schizophrenia. As a trend, the PET Scans are showing damage to the functioning of two primary lobes of the brain -- the frontal and the temporal. The frontal lobes are in the front of the head, and the temporal lobes are on the lower sides. Other deeper and central smaller brain areas are also implicated at times.
PET Scan research has reached to over 155 studies that include 4043 patients with 3977 normal controls (Davidson LL, Psychiatric Research. 2003;122:69ff). While it is not definitive in diagnosing every schizophrenic, certain patterns like those mentioned above are common, and since they were not found in patient XX, lend support to the automobile trauma as the cause of the patient's psychosis.
However, perhaps more important is the negative evidence. Meaning, the research does not support the pattern found in his scan. If the scan were fitting of Schizophrenia one would expect patterns mentioned above or a normal pattern falling below detection. But not clearly positive damage, which does not appear to fit with the thousands of patients previously published. An accident would tend to create a wide range of possible patterns due to trauma variation.
His PET Scan reports a clearly positive finding—it was abnormal. Basically finding a pathological process affecting many regions of the right hemisphere, but most pronounced in the temporal and parietal lobes of the brain, and also affecting deeper sub-cortical nuclei. They felt the results were consistent with head trauma.
Since the [RESPECTED MEDICAL UNIVERSITY] had a large range of Psychiatric, Psychological and Neurological studies going on around the time of the PET Scan, I would be careful about quick dismissals of radiologists who were seeing a very wide range of PET Scan pathology, and certainly Schizophrenia which effects 1% of the population.
Also, while the American Academy of Neurology half a decade ago (1998) did not feel PET Scans should be the defining evidence in forensics, their Continuing Medical Education offerings, publications and Fellowships show a strong respect for this technology, and hardly consider it useless clinically.
"Head Trauma Never Causes Psychosis" True?
I was surprised to read in Mr. Z's Neuropsychological Evaluation that "mild head injuries do not cause schizophrenia ... nor hallucinations ... or other stigmata of serious mental illness" (page x). Also, Dr. Y's neuropsychiatric evaluation reports that if one has "classic signs of Schizophrenia such as paranoid thinking and delusions, it cannot be due head trauma" (pg. x). He does admit that visual hallucinations are less common in Schizophrenia and may point more to a "toxic delirium."
My first appeal would be that patient X's so-called "mild" head injuries were not diagnosed as mere head massage. The diagnoses soon after the incident include:
Initial neuropsychological testing by Dr. T in 19XX found:
"Schizophrenia-like" psychosis is quite common after head trauma. In Psychological Medicine, 45 patients with head trauma showed psychosis, which slowly developed over an average of 54 months often with common schizophrenia appearing prodromal symptoms and with different courses, including a significant number with a chronic course (Sachdev, P. 2001;31:231ff). Another study points to an average 2-year delay before psychosis develops after brain trauma.
Brain trauma is such a serious possible precursor to "schizophrenia-like psychosis" that Zhang reports they overlap—considerably. In addition, Zhang notes the psychosis after the brain trauma is often gradual and commonly chronic (Current Psychiatry Reports. 2003;5:197ff).
Indeed, major texts on this topic such as Neurobehavioral Disability and Social Handicap Following Traumatic Brain Injury (R. Wood & TM McMillan) and Concussive Brain Trauma (RS Parker), present evidence of routine sequellea after even modest concussions in many patients, which are consistent with many of this patient's functional declines.