Biological factors associated with susceptibility to posttraumatic stress disorder

Because only a proportion of persons exposed to traumatic events develop posttraumatic stress disorder (PTSD), it has become important to elucidate the factors that increase the risk for the development of PTSD following trauma exposure as well as the factors that might serve to protect individuals from developing this condition. Putative risk factors for PTSD may describe the index traumatic event or characteristics of persons who experience those events. Recent data have implicated biological and familial risk factors for PTSD. For example, our recent studies have demonstrated an increased prevalence of PTSD in the adult children of Holocaust survivors, even though these children, as a group, do not report a greater exposure to life-threatening (Diagnostic and Statistical Manual of Mental Disorders [DSM-IV] Criterion A) events. These studies are reviewed. It is difficult to know to what extent the increased vulnerability to PTSD in family members of trauma survivors is related to biological or genetic phenomena, as opposed to experiential ones, because of the large degree of shared environment in families. In particular, at-risk family members, such as children, may be more vulnerable to PTSD as a result of witnessing the extreme suffering of a parent with chronic PTSD rather than because of inherited genes. But even if the diathesis for PTSD were somehow "biologically transmitted" to children of trauma survivors, the diathesis is still a consequence of the traumatic stress in the parent. Thus, even the most biological of explanations for vulnerability must at some point deal with the fact that a traumatic event has occurred.

Neuroendocrine activity and memory-related impairments in posttraumatic stress disorder

This article reviews memory-related impairments in trauma survivors with posttraumatic stress disorder and their possible association to neuroendocrine alterations seen in this disorder. The neuroendocrine profile in PTSD first described in chronically ill combat veterans is characterized by lower basal cortisol levels, higher glucocorticoid receptor number, enhanced sensitivity to exogenous steroids, and increased variation in basal cortisol levels over the diurnal cycle. The generalizability and time course of these neuroendocrine alterations are explored in longitudinal studies and studies in other traumatized populations. These studies suggest that at least some aspects of this neuroendocrine profile can also be seen in other populations, including women, children, and victims of childhood trauma. Additionally, the alterations may be present early in the course of illness, perhaps even in the immediate aftermath of trauma, and may continue to be manifest in elderly trauma survivors. The mechanisms by which these neuroendocrine alterations may influence the formation and processing of traumatic memories are discussed.

Predicting the development of posttraumatic stress disorder from the acute response to a traumatic event

Posttraumatic stress disorder (PTSD) is a psychiatric condition that is directly precipitated by an event that threatens a person's life or physical integrity and that invokes a response of fear, helplessness, or horror. In recent years it has become clear that only a proportion of those exposed to fear-producing events develop or sustain PTSD. Thus, it seems that an important challenge is to elucidate aberrations in the normal fear response that might precipitate trauma-related psychiatric disorder. This paper summarizes the findings from recent studies that examined the acute and longer term biological response to traumatic stress in people appearing to the emergency room immediately following trauma exposure. In the aggregate, these studies have demonstrated increased heart rate and lower cortisol levels at the time of the traumatic event in those who have PTSD at a follow-up time compared to those who do not. In contrast, certain features associated with PTSD, such as intrusive symptoms and exaggerated startle responses, are only manifest weeks after the trauma. The findings suggest that the development of PTSD may be facilitated by an atypical biological response in the immediate aftermath of a traumatic event, which in turn leads to a maladaptive psychological state.

Vulnerability to posttraumatic stress disorder in adult offspring of Holocaust survivors

OBJECTIVE

There has been considerable controversy regarding the impact of the Holocaust on the second generation, but few empirical data are available that systematically document trauma exposure and psychiatric disorder in these individuals. To obtain such data, the authors examined the prevalence of stress and exposure to trauma, current and lifetime posttraumatic stress disorder (PTSD), and other psychiatric diagnoses in a group of adult offspring of Holocaust survivors (N=100) and a demographically similar comparison group (N=44).

METHOD

Subjects were recruited from both community and clinical populations and were evaluated with the use of structured clinical instruments. Stress and trauma history were evaluated with the Antonovsky Life Crises Scale and the Trauma History Questionnaire, PTSD was diagnosed with the Clinician Administered PTSD Scale, and other psychiatric disorders were evaluated according to the Structured Clinical Interview for DSM-IV.

RESULTS

The data show that although adult offspring of Holocaust survivors did not experience more traumatic events, they had a greater prevalence of current and lifetime PTSD and other psychiatric diagnoses than the demographically similar comparison subjects. This was true in both community and clinical subjects.

CONCLUSIONS

The findings demonstrate an increased vulnerability to PTSD and other psychiatric disorders among offspring of Holocaust survivors, thus identifying adult offspring as a possible high-risk group within which to explore the individual differences that constitute risk factors for PTSD.

Plasma norepinephrine and 3-methoxy-4-hydroxyphenylglycol concentrations and severity of depression in combat posttraumatic stress disorder and major depressive disorder

BACKGROUND

Catecholamines are thought to play a significant role in the pathophysiology of posttraumatic stress disorder (PTSD), but findings in PTSD have been discrepant.

METHODS

To obtain more information about catecholamine activity in PTSD, we sampled plasma norepinephrine (NE) and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations over a 24-hour period in men with PTSD (n = 15) and major depressive disorder (MDD) (n = 12), and nonpsychiatric comparison subjects (n = 13), under unstimulated conditions. Chronobiological analyses were performed to determine possible changes in the circadian and ultradian release of these hormones.

RESULTS

Significant group differences were present for mean plasma NE levels (p = .03), but not MHPG. NE levels were significantly associated with severity of depression in the PTSD group (p = .002). Therefore, PTSD subjects were further subdivided into those with and without a comorbid secondary depression. Increased NE levels were only present in PTSD subjects who did not have a secondary depression. This study also found no significant group differences on any of the chronobiological parameters.

CONCLUSIONS

The results clarify that increased NE levels in PTSD may be confined to the subgroup of subjects who do not have comorbid depression, and as such, may help resolve some of the discrepancies in the literature regarding basal catecholamine activity.

Predictors of cortisol and 3-methoxy-4-hydroxyphenylglycol responses in the acute aftermath of rape

BACKGROUND

Prospective studies of trauma survivors can provide information about the relationship between rape characteristics and the development of subsequent symptoms.

METHODS

The present study examined the relationship of prior assault, rape severity, posttraumatic stress disorder (PTSD) symptoms following rape, and subsequent PTSD diagnosis, to the acute cortisol and 3-methoxy-4-hydroxyphenylglycol (MHPG) response to this traumatic event in 20 women.

RESULTS

Women with a history of prior physical or sexual assault showed a significantly attenuated cortisol response to the acute stress of rape compared to women without such a history. MHPG appeared to be associated with injury-related rape characteristics, and symptoms of active avoidance, but not prior history. PTSD status at the 3-month follow-up was predicted by both a prior history of assault and high injury rape, but was not directly predicted by either cortisol or MHPG levels. MHPG and cortisol were not correlated in the sample as a whole, but were correlated among individuals who did not subsequently develop PTSD (p = .04)

CONCLUSIONS

The results suggest that different neuroendocrine systems may mediate different components of the response to traumatic stress.

Psychoneuroendocrinology of post-traumatic stress disorder

In 1980, the diagnosis of post-traumatic stress disorder (PTSD) was established to describe the long-lasting symptoms that can occur following exposure to extremely stressful life events. This article reviews the findings of neuroendocrinologic alterations in PTSD and summarizes the finding of hypothalamic-pituitary-adrenal (HPA), catecholamine, hypothalamic-pituitary-thyroid (HPT) and hypothalamic-pituitary-gonadal (HPG) systems. These are the neuroendocrine systems that have been studied in PTSD. Also included is a review of the basic facts about PTSD and biologic data.

Relationship between posttraumatic stress disorder characteristics of Holocaust survivors and their adult offspring

OBJECTIVE

There is controversy regarding the long-lasting effects of the Holocaust on the adult children of Holocaust survivors. In the present study the authors examined the relationship between posttraumatic stress disorder (PTSD) characteristics of Holocaust survivors and their adult children to determine whether differences in symptom severity or diagnostic status of parents would be associated with similar characteristics in their adult children.

METHOD

Holocaust survivors (N = 22) and their offspring (N = 22) were interviewed with several instruments to assess lifetime trauma history, effect of trauma on one's life, level of intrusive and avoidance symptoms in response to reminders of the Holocaust, current and lifetime PTSD, and current and lifetime axis I psychiatric disorder other than PTSD.

RESULTS

There were significant relationships between parents and children regarding the effect of trauma on one's life and level of intrusive, but not avoidance, symptoms in response to reminders of the Holocaust. Offspring with traumatic events were more likely to develop PTSD if their parents had PTSD.

CONCLUSIONS

Symptoms in offspring may be related to presence and severity of symptoms in the parent. Furthermore, PTSD in the parent may be a risk factor for PTSD in offspring.

Relationship between 3-methoxy-4-hydroxyphenylglycol and homovanillic acid in saliva and plasma of healthy volunteers

Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) levels may reflect changes in central noradrenergic and dopaminergic activity, respectively. The relationship between MHPG and HVA in saliva and plasma was investigated to evaluate the utility of salivary metabolite measurement as a relatively noninvasive and useful alternative to plasma analysis. MHPG and HVA in saliva and plasma, collected concurrently, from 12 healthy volunteers, were measured by high-performance liquid chromatography. Concentration of free MHPG in saliva correlated significantly with plasma free MHPG. Salivary free MHPG was significantly higher than in plasma. Enzymatic hydrolysis of conjugated MHPG corroborated other work that plasma free MHPG, MHPG-glucuronide, and MHPG-sulfate were in roughly equal proportions. Unpredictably, in saliva, free MHPG was greater than 80% of the total. Salivary and plasma free HVA concentrations also correlated significantly, but salivary HVA levels were significantly lower than in plasma. Conjugated HVA was consistently less than 10% of total both in saliva and plasma. These findings suggest that salivary MHPG and HVA can reflect plasma metabolite levels. Although local factors may influence their formation and concentration in saliva, large changes in plasma free MHPG or HVA could be reflected by parallel changes in saliva.

Enhanced dexamethasone suppression of plasma cortisol in adult women traumatized by childhood sexual abuse

A study was undertaken to determine if female survivors of childhood and/or adolescent sexual abuse (CSA) would exhibit hypothalamic-pituitary-adrenal (HPA) axis abnormalities characteristic of patients with combat-related posttraumatic stress disorder (PTSD)--i.e., enhanced cortisol suppression to low-dose dexamethasone and increased density of lymphocyte glucocorticoid receptors. Nineteen women who reported experiencing severe CSA and 21 nonvictimized women participated in a low-dose (0.5 mg) dexamethasone suppression test and donated blood for measurement of lymphocyte glucocorticoid receptor binding. Women with CSA had significantly enhanced suppression of plasma cortisol in response to 0.5 mg dexamethasone compared to the nonvictimized women. These observations are consistent with findings in male veterans with combat-related PTSD. They suggest that this pattern of HPA axis dysfunction may be a characteristic sequel of psychiatric disorders that occur following a range of traumatic experiences. This HPA axis profile is different than that associated with acute stress or with major depressive disorder.

Reduced sensitivity to glucocorticoid feedback and reduced glucocorticoid receptor mRNA expression in the luteal phase of the menstrual cycle

We examined the effects of the menstrual cycle on hypothalamic-pituitary adrenal axis regulation in healthy women with no history of psychiatric illness by measuring plasma cortisol responses to a low-dose (0.25 mg) of dexamethasone (N = 23) and by measuring glucocorticoid receptor (type II) mRNA expression in lymphocytes using Northern blotting (N = 19). Both measures were performed in the early follicular and mid-luteal phases of the menstrual cycle. Dexamethasone suppression of plasma cortisol was greater in the follicular phase of the menstrual cycle compared to the mid-luteal phase (p < .01). In addition, type II glucocorticoid receptor mRNA expression in lymphocytes was 78% higher in the follicular phase compared to the mid-luteal phase (p < .02). These results indicate that glucocorticoid feedback regulation of the hypothalamic-pituitary-adrenal axis is reduced in the mid-luteal phase of the menstrual cycle. Reduced feedback regulation of central stress response systems may play a role in generation of common premenstrual symptoms of irritability and dysphoria.

Individual differences in posttraumatic stress disorder symptom profiles in Holocaust survivors in concentration camps or in hiding

Symptom patterns were compared between Holocaust survivors in concentration camp (n = 70) and those who were in "hiding" (n = 30) during the war. The impact of age at the time of the trauma, gender, and cumulative lifetime stress, and the effect of each of these variables controlling for the others, on posttraumatic stress disorder (PTSD) symptoms were also evaluated. A significant negative relationship between age at the time of the trauma and symptoms of psychogenic amnesia, hypervigilence and emotional detachment, and a positive correlation between age and intrusive thoughts, were observed. Cumulative lifetime stress was positively associated with symptoms of avoidance. The study provides the first empirical data regarding the factors that potentially explain individual differences in PTSD symptom patterns in Holocaust survivors.

Relationships between hormonal profile and novelty seeking in combat-related posttraumatic stress disorder

This study examines relationships between hormonal levels and novelty seeking in a group of 27 Vietnam veterans with combat-related posttraumatic stress disorder (PTSD). Novelty seeking in the veteran sample, measured by the Cloninger Tridimensional Personality Questionnaire (TPQ), was almost twice as high as previously published norms. A distinctive pattern of significant positive correlations was found between novelty seeking scores and serum total triiodothyronine (T3), free T3, the T3/free thyroxine (FT4) ratio, urinary norepinephrine and the norepinephrine/cortisol ratio, while a negative correlation was found between novelty seeking scores and urinary cortisol levels. The findings were confirmed by t test analyses of high vs low novelty seeking subgroups and do not appear to be related simply to the severity of PTSD. These preliminary findings indicate the need to include measures of characterological traits in psychoendocrine studies of PTSD and to investigate their possible usefulness in subtyping this disorder.