Philosophically, neuropsychologists believe the disorders they evaluate are of a natural kind: biologically real and existing independently of our means of classifying them, much like viruses or atomic structures exist separately from cultural outlook (McNally, 2004). We do not like to believe historical influences affect our evaluations, and nobody likes the idea that cognitive disorders can be created by merely marketing their existence. Social and cultural factors cannot be avoided when neuropsychologists move away from well-defined cerebral disorders to the study of subjectively defined disorders. Shorter (1994) elaborated the fluid presentation of hysteria over time, and ill-defined “railway spine” syndromes emerged when railroad accidents became compensable in 1800's Great Britain but not for orchard workers with similarly abrupt orthopedic strains. For a current controversy, consider how rising autism rates are believed to be biologically determined (e.g., mercury in vaccines) even though research underscores a proportional decline in mental retardation rates and autism rates still climbed long after mercury preservatives were eliminated in Denmark (Madsen et al., 2003). I refer to diagnostic “bracket creep” (e.g., “defining deviancy down” or “up” in the case of retardation), and “medicalization of misery,” variants of the idea that cultural pressures influence the vocabulary and scope of our inquiries. This can lead to increasing heterogeneity of our diagnostic categories, becoming a potentially insurmountable obstacle for those determined to discover a specific neurobiology for psychological suffering. Posttraumatic stress disorder (PTSD) is a myriad symptom constellation with widening boundaries under increasing neurocognitive scrutiny.

The Neuropsychology of PTSD: Biological, Cognitive, and Clinical Perspectives, edited by Jennifer Vasterling and Chris Brewin, is intended to examine neurocognitive correlates of post-traumatic syndromes from diverse perspectives. The title implies PTSD is ahistorical and a disorder of the natural kind; and many of the thirteen chapters within five sections are variations on this theme. Some authors are strong advocates of a pure neurobiological model as if a well-established fact, others propose weaker somatic models that emphasize person–environment interactions, and some recognize that vexing validity problems make specific cause–effect statements inadvisable. Several chapters are highly technical, and the inexperienced reader may need assists to understand the biochemical and genetic terminology.

The first section's one chapter (Duke and Vasterling) reviews epidemiological and methodological issues as they bear on neuropsychological functioning. The authors do a masterful job of summarizing PTSD definitions, prevalence, risk and resiliency factors, natural history, and psychiatric comorbidities. They clearly catalog specific methodological and inferential issues that complicate PTSD research and offer concrete advice to correct problems during the design phase (e.g., don't do ANCOVA). Section II, Biological Perspectives, focuses on somatic modeling of PTSD. Chapter two (Southwick, Rasmussen, Barron, and Arnsten) summarizes studies of neurotransmitter and limbic system interactions during cognitive appraisal of threat. The authors advance a testable hypothesis, which I shall term the “frontal-amygdalar imbalance” model. That is, norepinephrine pulses suppress inhibitory outflow of the prefrontal cortex, thereby increasing amygdala excitability with attendant irrational fear reactions. This is a strong (albeit technically dense) chapter that ranges from gross anatomy to molecular analysis of stress neurophysiology. Especially interesting were methods for creating transient frontal lobe syndromes in volunteers, such as the tryptophan depletion technique. Chapter 3 (Shin, Rauch, and Pitman), less technically demanding, addresses structural and functional neuroimaging studies including resting and activated SPECT/PET/fMRI studies of the hippocampus, medial prefrontal cortex, and amygdala. These authors force divergent findings into the frontal-amygdalar imbalance model. One intriguing finding is that lower hippocampal volume predates trauma, suggesting it is a risk factor and not an acquired problem. Chapter 4 (Metzger, Gilbertson, and Orr) maintains a disciplined focus on event-related potentials (ERP) and argues ERP is well suited to investigating symptoms such as hypervigilance and reduced concentration. The authors render complex issues into understandable terms, and readily acknowledge lack of clinical specificity when ERP-PTSD findings are viewed in a broader psychiatric context. A problem with this approach is deciding which ERP predictions are valid; some ERP studies find reduced sensory gating (consistent with hypervigilance) but others find attenuation (consistent with avoidance). Hence, any group effects for ERP can be made consistent with PTSD in post hoc fashion.

Section III, Cognitive and Information-processing Perspectives, takes a purely cognitive psychology perspective. Premised on the theory that PTSD patients should show attentional biases under mild threat conditions, author Constans (chapter 5) reviews cognitive psychology paradigms such as: dot probe following threat words; “emotional Stroop” reaction time; subjective biases of various types; and directed forgetting. Constans concludes that findings are contrary to expectations of involuntary perceptual biases. He reports unconscious attentional bias for persons with clinical anxiety and more pedestrian trait anxiety, but not in various PTSD groups. Instead PTSD–control differences appear with tasks requiring more deliberative processing, raising an issue of volitional contributions to performance. Brewin (chapter 6) focuses on traumatic memories from a cognitive perspective. Six pages are devoted to memory research from everyday life and PTSD patients, but the remainder is a theoretical exposition on single and multiple representation memory systems. Brewin provides some understandable context by discussing hippocampal and amygdalar roles in memory, but the speculative nature of his discussion is a problem throughout his three chapters.

Section IV, Developmental and Population-specific Perspectives, details PTSD variants during developmental stages or in specific populations. Chapter seven (Bellis, Hooper, and Sapia) impressively catalogues studies of anatomical and biochemical correlates of early trauma exposure. Topics include associations between childhood trauma and brain development, MRI findings, limbic-hypothalamic responsivity, theory of mind, and cognitive function. This is the only chapter that addresses dose-response relations, albeit briefly. Although satisfying and informative, the chapter is vague about the nature and quantification of childhood stressors, casually lumping together the two distinct concepts of “neglect” and “abuse.” Vasterling and Brailey (chapter 8) review neuropsychological findings in adults, using the familiar organization by domain: intellectual, attentional, executive, episodic, and implicit memory function. They do an excellent job of integrating this vast literature to propose a testable PTSD pattern: Mild sustained attention and initial memory acquisition problems against a background of intact executive, language, and perceptual-motor functioning, qualified by noting similar neurocognitive patterns in other psychiatric groups. They also report lower intelligence that correlates negatively with PTSD symptom frequency, a crucial consideration when faced with “subtle” deficit issues, common in neuropsychological populations. The contribution of Yehuda et al. in chapter 9 on aging and trauma is not a true chapter; they report a study of list learning in older trauma survivors. Contrary to claims elsewhere in this book, Figures 9.1, 2, 3, 4, 5, 6, 7, 8, and 9.4 (p. 223) show that older Holocaust survivors who had entered death camps at young ages had markedly better verbal learning scores than American veterans reporting first traumas in their late 20's. Translation: A reverse dose-response effect. The authors futilely struggle to find a unified neurobiological explanation, but unfortunately there was no symptom validity testing. This chapter required a better description of circadian rhythms, as Yehuda et al. questionably assert that aging PTSD patients show a “distinctive” attenuation of the daily cortisol cycle. But, dampened circadian rhythms (e.g., core body temperature) are the rule in normal aging. Chapter 10 is relevant to private practitioners: Dual diagnosis of PSTD and TBI. Brewin and coauthor write another overly theoretical piece, this time trying to explain away conceptual problems in dual diagnosis rather than carefully weighing the empirical evidence supporting/disputing it. The authors make the questionable argument that PTSD should be diagnosed in TBI patients not meeting conventional criteria. As hinted in my introduction, neuropsychologists concerned about how diagnostic elasticity affects research need look no further than this chapter.

Section V addresses Clinical Applications. Only Vasterling and Kleiner (chapter 11) offer useable advice. Their history-gathering recommendations are multi-faceted and nicely nuanced, but the plethora of comorbidities they list are daunting and raise an issue of over-reporting. Their neuropsychological test battery recommendations however are generic and more speculative. This is not the authors fault: Outside of expected “mild” relative weaknesses on generic memory and attention tests, there is no empirically demonstrated signature for PTSD on specific tests, and pretrauma g remains an issue (cf. chapter 8). Disappointingly, Brewin's broad speculations on treatment implications (chapter 12) meander around with little direction. A discussion of cognitive-behavioral therapy, a natural fit for this book, is absent, yet space is given for the eccentric EMDR. Brewin does not attempt to map cognitive and biological psychology terms into the vocabulary of psychotherapy, and the esoteric language defeats translation into therapeutic technique, to whit: “From the perspective of dual-representation theory, hotspots may correspond to moments where there was maximal separation between visual-spatial and verbal processing, leading to a large discrepancy between the contents of the respective memory systems” (p. 285). Friedman brings the reader back to earth with pharmacological approaches (chapter 13). This chapter serves as a quick review of adrenergic and pituitary axis chemistry, followed by studies of psychotropic use in PTSD. At times, the list of in-text citations is numbingly long with insufficient detailing of the best study outcomes, but this chapter is useful for those desiring an exhaustive list of primary source material in disorder-specific pharmacology.

The book's main weakness is lack of an integrative chapter distilling main ideas and conceptual problems. For example, the book did not inform about the best study population. This silence leaves an unsettling implication that traffic crashes minor and major, any head injury, rape, torture, robbery, one-time Sarin attacks, combat of unknown frequency, childhood abuse of any type and duration, and years brutalized in a Nazi death camp are interchangeable as “trauma.” Issues of severity stressor, its quantification, and its independent verification, as well as evidence for dose-response relations, are touched on but mostly neglected. There are necessary steps before considering any cause–effect reasoning about neurobiological implications in individual cases. A related elephant in the room is the wildly varying PTSD prevalence rates reported in the book. The alleged prevalence of full and subclinical post-Vietnam PTSD is 50% (National Readjustment Study), yet only 15% of all veterans were assigned combat roles (Satel, 2004). It is reasonable to conclude that decidedly nonbiological influences impact symptom reporting and interpretation. Other contradictory findings are juxtaposed without irony or comment. For example, we are treated to the interpretation that PTSD is present in 27% of persons with moderate TBI (Bryant et al., 2000). Even though the Bryant et al. findings just suggest prominent irritability in TBI, the chapter authors jump to a deus ex machina conclusion that PTSD-TBI must regularly coexist to justify speculating about it. The symptom overlap between PTSD and other disorders is large and lower hippocampal volumes have been reported in other patient groups. The book omits the animal literature. For example, it is well known that tame animals have smaller amgydalas than their wild counterparts. In this light, a finding of slightly lower amygdala volume in PTSD patients (chapter 3) is of unclear significance. Animal studies might help to cut through comorbidity clutter and more directly address the hypothesis that stress by itself causes specific structural brain changes. My final issue is the questionable practice of relying on global chart diagnoses. There was little focus on core symptoms, and no investigation of “numbing” or exaggerated startle reflex. Given DSM-IV's combinatory rules for seventeen PTSD symptoms, many patients sharing few symptoms can be diagnosed with PTSD. A consensus about which symptoms are core and which are peripheral is needed before human neurobiology even starts to enter the picture.

I recommend this book. Although in my view this volume provides better evidence for the nonspecificity of PTSD-Cognitive correlates and a need for better effort testing, the stronger chapters (e.g., any by Vasterling) carry the book and provide excellent overviews, informative descriptions of exciting new techniques of great interest to neuropsychologists, and comprehensive reference lists in this well-cited book. Clinicians can improve their differential diagnostic acumen when faced with individual PTSD patients, but treatment-oriented neuropsychologists will find little here.