Abstract
Over the past decade, Rachel Yehuda has brought her remarkable scientific gifts to bear on the field of neuroendocrinology in psychological trauma. In the process, she marshals impressive evidence validating posttraumatic stress disorder (PTSD), itself considered part of a heterogeneous group of clinical responses to trauma. She summarises her studies of progressive sensitisation of the hypothalamic-pituitary-adrenal (HPA) axis, as part of a well-integrated survey of the psychobiology of PTSD. Yehuda has made a number of important discoveries. Perhaps the most significant of these is the finding that, contrary to the beliefs of Selye and his followers, biological responses to trauma are discontinuous with those occurring at lower levels of stress. Findings in PTSD are also the reverse of those in depression, with lower levels of cortisol, and increased responsiveness of glucocorticoid receptors. Yehuda interestingly raises the possibility that half of depressive patients failing to evince hypercorticolism and dexamethasone non-suppression could be occult cases of PTSD.
Breslau's Detroit Area Survey of Trauma is at the cutting edge of current epidemiological studies. Everybody is exposed to trauma! However, only about 10% develop PTSD, challenging the notion that PTSD is a ‘normal response to abnormal stress’. Type of trauma, particularly exposure to violence, is a notable risk factor. Traumatic grief contributes highly. A considerable proportion of cases of PTSD fail to remit. Comorbid relationships are complex and yet to be elucidated. Breslau believes that trauma does not play an aetiological role in other psychiatric disorders in those who do not develop PTSD.
Shalev and Yehuda critically examine prospective studies of the evolution of PTSD. They advocate longitudinal path analysis in determining sequential causality. Peritraumatic dissociation is an important predictor. Genetic factors contribute as much as 30%. High sympathetic activation and low HPA activity result in consolidation of traumatic memories and also predict PTSD. The relationship between acute stress reactions and PTSD, and the progression from acute to chronic PTSD are currently under investigation. Exposure produces ‘sensitisation’ in some, and ‘immunisation’ in others. Chronic PTSD may be an independent psychobiological and nosological entity, and may not simply reflect a failure of recovery from the acute disorder.
Neuroimaging studies are promising but still few, write Rauch et al. Methodological pitfalls abound. Discerning pre- from post-event changes are nowhere more challenging! Studies are slowly evolving from naturalistic to hypothesis-driven approaches. Methods range from structural neuroimaging to a range of functional approaches, including symptom provocation studies, and neutral state and cognitive activation paradigms. Graded neuro-anatomical changes found thus far may be characteristic of the spectrum of anxiety disorders rather than PTSD per se. However, hippocampal volumes could be reduced, there may be a rightward shift in hippocampal-parahippocampal activity, paralimbic regions and the amygdala may be activated, and Broca's area de-activated. Anatomical substrates and receptor profiles are currently being characterised, and ‘cognitive probes’ refined and applied.
The treatment chapters focus on pharmacotherapy followed by cognitive-behavioural therapy. Marshall et al. allude to informed consent without actually mentioning it by name. Treatment selection for PTSD is still unable to draw on randomised controlled studies (RCTs) comparing psychosocial and pharmacological treatments. The authors thus advocate informed eclecticism, integrating drug and psychological treatment. Comorbid disorder must be addressed. Algorithms would be useful. Exploration and timing of treatment of trauma are controversial. Intervention may be unnecessary in the acute phase, but may prevent the development of chronic PTSD. Drugs, however, are symptomatic and supportive rather than curative. Goals are necessarily modest. Nowhere is this clearer than in Vietnam veterans with chronic PTSD, the principal target population for drug treatment studies. Tricyclic antidepressants remain the best studied drug class. There has been only one placebo-controlled trial with a selective serotonin re-uptake inhibitor (SSRI). Moderate improvement occurred with hyperarousal and numbing and with other core symptoms of PTSD. Cumulative childhood trauma was negatively correlated with pharmacotherapy response, indicating that these disorders require broader-based treatment. Benzodiazepines appear to represent a scatter-gun approach, with potential for doing more harm than good. The mood stabilisers lithium, carbamazepine, and valproic acid confer equivocal benefit, and neuroleptics are not recommended.
Foa and Meadow's chapter on psychosocial treatments of PTSD gives a singular view of psychosocial counselling. The current spate of stage models are eschewed. Negative treatment effects are regrettably not covered. The authors outline seven ‘gold standards’ for treatment outcome standards. Not surprisingly, few approaches meet these. But should they all? Increasingly there are calls for naturalistic studies to complement RCTs. Hypnotherapy and psychodynamic treatment are quickly passed over for a detailed presentation of cognitive-behavioural therapy. Stress inoculation, cognitive restructuring, and cognitive processing therapy all have empirical support, but prolonged exposure has most and is thus preferred. It is also apparently the easiest to perform, having five components: information gathering, psychoeducation, breathing retraining, imaginal exposure (reliving the trauma), and in vivo exposure (confrontation with trauma reminders).
Yehuda concludes that trauma and PTSD are not synonymous. Nor is there a dose-response relationship between the severity of the traumatic event and the development of PTSD. The book is replete with such useful reminders. Cognitive appraisal is paramount, as are prior stress, coping style and preexisting psychopathology. Trauma clearly encompasses a range of nosological responses. These are, however, not explored beyond PTSD. This book appeals more to the researcher than the clinician, but research findings do not readily generalise to clinical applications. As such, it is a useful but only partial glimpse of the field of PTSD.