Biomedical subjects

S M Southwick

Publications and source records attributed to S M Southwick.

At least 55 records · Page 3Linked to original sources

PubMed1996

Baseline startle amplitude and prepulse inhibition in Vietnam veterans with posttraumatic stress disorder.

Although an exaggerated startle response is a symptom of posttraumatic stress disorder (PTSD), empirical support for elevated baseline startle in PTSD has been weak. The present study investigated the eyeblink component of the acoustic startle reflex and prepulse inhibition (PPI) in 21 unmedicated Vietnam veterans with PTSD and in 17 civilian and 10 combat veteran comparison subjects. Patients with PTSD exhibited normal acoustic startle amplitude, but showed a significant reduction in PPI relative to the civilian subjects. There was only a trend toward a reduction in PPI in the PTSD group compared with the combat control group. The study does not support the hypothesis of exaggerated baseline startle in Vietnam veterans with PTSD but suggests abnormal startle modulation by a prepulse (i.e., PPI). Discrepancies between studies concerning the amplitude of startle in PTSD are discussed.

Acoustic Stimulation↗

PubMed1996

Noradrenergic mechanisms in stress and anxiety: I. Preclinical studies.

There is considerable preclinical evidence for a relationship between noradrenergic brain systems and behaviors associated with stress and anxiety. The majority of noradrenergic neurons are located in the locus coeruleus (pons), with projections throughout the cerebral cortex and multiple subcortical areas, including hippocampus, amygdala, thalamus, and hypothalamus. This neuroanatomical formation of the noradrenergic system makes it well suited to rapidly and globally modulate brain function in response to changes in the environment, as occurs during the presentation of stressors. Stress exposure is associated with an increase in firing of the locus coeruleus and with associated increased release and turnover of norepinephrine in brain regions which receive noradrenergic innervation. Increased firing of the locus coeruleus is also associated with behavioral manifestations of fear, such as arched back and piloerection in the cat. Exposure to chronic stress results in long-term alterations in locus coeruleus firing and norepinephrine release in target brain regions of the locus coeruleus. Norepinephrine is also involved in neural mechanisms such as sensitization and fear conditioning, which are associated with stress. These findings are relevant to an understanding of psychiatric disorders, such as panic disorder and post-traumatic stress disorder (PTSD), the symptoms of which have been hypothesized to be related to alterations in noradrenergic function.

Adrenergic Fibers↗

PubMed1996

Noradrenergic mechanisms in stress and anxiety: II. Clinical studies.

Studies in animals have shown a relationship between alterations in noradrenergic brain system function and behaviors of anxiety and fear. These findings have generated the hypothesis that the symptoms seen in patients with anxiety disorders may be related to alterations in noradrenergic function. A number of clinical studies have tested this hypothesis, utilizing measures of catecholaminergic function such as heart rate and blood pressure, measurement of norepinephrine and its metabolites in urine and plasma and adrenergic receptor binding in platelets, as well as pharmacological challenge to the noradrenergic system. Acute stressors, such as public speaking, have been associated with an increase in heart rate, blood pressure, and norepinephrine and its metabolites in urine and plasma. Findings in patients with panic disorder at baseline related to heart rate, blood pressure, baseline norepinephrine and its metabolites, and platelet adrenergic receptors have been mixed, while the most consistent findings have been blunted growth hormone response to clonidine and increased 3-methoxy-4-hydroxy-phenylethylene-glucol (MHPG) and anxiety following stimulation of the noradrenergic system with yohimbine. Baseline measures of noradrenergic function in patients with posttraumatic stress disorder (PTSD) have also been mixed, while an increased heart, blood pressure and norepinephrine response to traumatic reminders, as well as increased behavioral (as well as different brain metabolic) response to yohimbine, have been found in PTSD. There are fewer studies of noradrenergic function in the other anxiety disorders, and the findings there have not been consistent. These studies provide evidence for increased noradrenergic responsiveness in panic disorder and PTSD, although there does not appear to be an alteration in baseline noradrenergic function in these patients.

Adrenergic Fibers↗

PubMed1996

Exaggerated acoustic startle reflex in Gulf War veterans with posttraumatic stress disorder.

OBJECTIVE: Exaggerated startle reflex is reputed to be one of the cardinal symptoms of posttraumatic stress disorder (PTSD). The goal of this study was to assess the magnitude of the acoustic startle reflex in Gulf War veterans with PTSD. METHOD: The eye-blink component of the startle reflex was measured in response to six blocks of pseudorandomized 40-msec white noise bursts of varying intensities (90, 96, 102, 108, and 114 dB) in 10 Gulf War veterans with PTSD, seven Gulf War veterans without PTSD, and 15 civilian subjects without PTSD. RESULTS: The magnitude of the first startle response, as well as the magnitude of startle response averaged across blocks of testing, was significantly greater in Gulf War veterans with PTSD than in veteran and civilian comparison groups. CONCLUSIONS: Consistent with some clinical studies investigating the startle response in Vietnam veterans with PTSD, this investigation provides evidence for exaggerated startle response in this disorder. Preclinical studies of shock sensitization of the startle response suggest that the higher levels of startle response seen in the PTSD subjects may reflect a sensitization of the fear/alarm response created by the stress of combat trauma.

Acoustic Stimulation↗

PubMed1996

Chronic PTSD in Vietnam combat veterans: course of illness and substance abuse.

OBJECTIVE: The purpose of this study was to measure the longitudinal course of specific symptoms of posttraumatic stress disorder (PTSD) and related symptoms of alcohol and substance abuse and the effects of alcohol and substances on the symptoms of PTSD. METHOD: A structured interview for the assessment of PTSD and alcohol and substance abuse, as well as other factors such as life stressors and treatment, was administered to 61 Vietnam combat veterans with PTSD. RESULTS: Onset of symptoms typically occurred at the time of exposure to combat trauma in Vietnam and increased rapidly during the first few years after the war. Symptoms plateaued within a few years after the war, following which the disorder became chronic and unremitting. Hyperarousal symptoms such as feeling on guard and feeling easily startled developed first, followed by avoidant symptoms and finally by symptoms from the intrusive cluster. The onset of alcohol and substance abuse typically was associated with the onset of symptoms of PTSD, and the increase in use paralleled the increase of symptoms. Patients reported a tendency for alcohol, marijuana, heroin, and benzodiazepines to make PTSD symptoms better, while cocaine made symptoms in the hyperarousal category worse. There was no relationship between treatment interventions and the natural course of PTSD. CONCLUSIONS: These findings suggest that symptoms of PTSD begin soon after exposure to trauma, that hyperarousal symptoms are the first symptoms to occur, that the natural course of alcohol and substance abuse parallels that of PTSD, and that specific substances have specific effects on PTSD symptoms.

Alcoholism↗

PubMed1996

Neural mechanisms in dissociative amnesia for childhood abuse: relevance to the current controversy surrounding the "false memory syndrome".

OBJECTIVE: There is considerable controversy about delayed recall of childhood abuse. Some authors have claimed that there is a "false memory syndrome," in which therapists suggest to patients events that never actually occurred. These authors point to findings that suggest that memory traces are susceptible to modification. The purpose of this paper is to review the literature on the potential vulnerability of memory traces to modification and on the effects of stress on the neurobiology of memory. METHOD: The authors review findings on mechanisms involved in normal memory function, effects of stress on memory in normal persons, children's memory of stressful events, and alterations of memory function in psychiatric disorders. The effects of stress on specific brain regions and brain chemistry are also examined. RESULTS: Neuropeptides and neurotransmitters released during stress can modulate memory function, acting at the level of the hippocampus, amygdala, and other brain regions involved in memory. Such release may interfere with the laying down of memory traces for incidents of childhood abuse. Also, childhood abuse may result in long-term alterations in the function of these neuromodulators. CONCLUSIONS: John Nemiah pointed out several years ago that alterations in memory in the form of dissociative amnesia are an important part of exposure to traumatic stressors, such as childhood abuse. The studies reviewed here show that extreme stress has long-term effects on memory. These findings may provide a model for understanding the mechanisms involved in dissociative amnesia, as well as a rationale for phenomena such as delayed recall of childhood abuse.

Amnesia↗

PubMed1996

Dissociation in aging Holocaust survivors.

OBJECTIVE: This study explored relationships among dissociation, trauma, and posttraumatic stress disorder (PTSD) in elderly Holocaust survivors with and without PTSD and in a demographically comparable group of nontraumatized subjects. METHOD: Holocaust survivors with PTSD (N = 35) and without PTSD (N = 25) who had been recruited from the community and a comparison group (N = 16) were studied. Dissociation was evaluated with the Dissociative Experiences Scale. Past cumulative trauma and recent stress were evaluated with the Antonovsky Life Crises Scale and the Elderly Care Research Center Recent Life Events Scale, respectively. PTSD symptoms were assessed with the Clinician-Administered PTSD Scale. RESULTS: The Holocaust survivors with PTSD showed significantly higher levels of current dissociative experiences than did the other groups. However, the extent of dissociation was substantially less than that which has been observed in other trauma survivors with PTSD. Dissociative Experiences Scale scores were significantly associated with PTSD symptom severity, but the relation between Dissociative Experiences Scale scores and exposure to trauma was not significant. CONCLUSIONS: Possible explanations for this finding include the age of the survivors, the length of time since the traumatic event, and possible unique features of the Holocaust survivor population. Nevertheless, the findings call into question the current notion that PTSD and dissociative experiences represent the same phenomenon. The findings suggest that the relationships among dissociation, trauma, and PTSD can be further clarified by longitudinal studies of trauma survivors.

Age Factors↗

PubMed1996

The psychobiological basis of posttraumatic stress disorder.

Posttraumatic stress disorder is a disorder with an identifiable etiological factor (exposure to a traumatic event) and with a complex symptomatology (i.e. intrusive memories, avoidance, hyperarousal) that suggests dysfunction in multiple psychobiological systems. This review considers studies of the neurobiological consequences of acute and chronic stress showing that traumatic experiences can produce long-lasting alterations in multiple neurochemical systems. The role of the locus coeruleus noradrenergic system, prefrontal cortex dopaminergic system, endogenous opiates, hypothalamic-pituitary-adrenal axis, and cortico-releasing factors are reviewed. Several models of PTSD are highlighted, including fear conditioning, kindling, and sensitization. In particular, fear conditioning to explicit and contextual cues is proposed as a model for intrusive memories reactivated by trauma-related stimuli and hyperarousal, respectively. It is argued that the amygdala plays a crucial role in the encoding and retrieval of fear memories activated by specific stimuli that have been associated with aversive events. Association involving more complex environmental stimuli and aversive events may require the involvement of the hippocampus and the bed nucleus of the stria terminalis. Repeated activation of conditioned fear memories may produce a kindling-like process which results in spontaneous intrusive memories.

Humans↗

PubMed1995

Fear-potentiated startle in posttraumatic stress disorder.

Exaggerated startle is reputed to be one of the cardinal symptoms of posttraumatic stress disorder (PTSD); however, objective studies have given conflicting results as to whether or not startle is increased in PTSD. The present study investigated startle in PTSD during the threat of shock (fear-potentiated startle). The eyeblink component of the startle reflex was measured at various times preceding and following the anticipation of unpleasant electric shocks in 9 PTSD subjects and 10 age-matched, healthy controls. Startle amplitude was significantly greater during baseline and during shock anticipation in the PTSD subjects, compared to the controls. Habituation of the startle reflex was normal. Because other studies in the literature, as well as in our own laboratory, have failed to find exaggerated startle at baseline (i.e., absence of stress) in PTSD patients, it is unlikely that the present results reflect a chronic elevation of startle in this group. Instead, the higher levels of startle in the PTSD group probably resulted from a greater conditioned emotional response in this group, triggered by anticipation of electric shocks that generalized to the unfamiliar experimental context in which testing occurred. Hence, emotionally charged test procedures may be especially informative in distinguishing PTSD patients from other psychiatric diagnostic groups.

Adult↗

PubMed1995

Functional neuroanatomical correlates of the effects of stress on memory.

Recently there has been an increase in interest in the relationship between stress and memory. Brain regions which are involved in memory function also effect the stress response. Traumatic stress results in changes in these brain regions; alterations in these brain regions in turn may mediate symptoms of posttraumatic stress disorder (PTSD). Neural mechanisms which are relevant to the effects of stress on memory, such as fear conditioning, stress sensitization, and extinction, are reviewed in relation to their implications for PTSD. Special topics including neural mechanisms in dissociation, neurobiological approaches to the validity of childhood memories as they apply to controversies over the "False Memory Syndrome," and implications of the effects of stress on memory for psychotherapy, are also reviewed. The findings discussed in this paper are consistent with the formulation that stress-induced alterations in brain regions and systems involved in memory may underlie many of the symptoms of PTSD, as well as dissociative amnesia, seen in survivors of traumatic stress.

Adult↗

PubMed1995

The therapeutic use of ritual and ceremony in the treatment of post-traumatic stress disorder.

The therapeutic purposes and effects of specially designed ceremonies in the treatment of persons with post-traumatic stress disorder are described. Ceremonies compartmentalize the review of the trauma, provide symbolic enactments of transformation of previously shattered relationships, and reestablish connections among family and with society in general. Four ceremonies used with Vietnam combat veterans are described which focus on the themes of separation from and return to the family, forgiveness of the living, and releasing the dead. Ritual and ceremony are highly efficient vehicles for accessing and containing intense emotions evoked by traumatic experience. Evaluation by family and veterans judge these ceremonies to be the most effective components of treatment.

Drama↗

PubMed1995

Yohimbine facilitated acoustic startle in combat veterans with post-traumatic stress disorder.

Preclinical and clinical studies have suggested that the acoustic startle reflex (ASR) is a useful model to investigate the neurochemical basis of anxiety and fear states. This work has revealed that the anxiogenic alpha-2 receptor antagonist, yohimbine, increases the amplitude of the ASR in laboratory animals and in healthy human controls. Because of the growing body of data that support the hypothesis that severe stress results in substantial alterations in noradrenergic neuronal reactivity, the present investigation evaluated the effects of yohimbine on the ASR of 18 patients with PTSD and 11 healthy combat controls. Subjects received IV yohimbine (0.4 mg/kg) or saline placebo on 2 separate days in a randomized double blind placebo control design. A trial of two tone frequencies with varied intensity (90, 96, 102, 108, 114 dB) white noise and instantaneous rise time, was delivered binaurally through headphones. Tones were delivered every 25-60 s, for a 40-ms duration. Startle testing was performed 80 min post-infusion and lasted 15-20 min. Yohimbine significantly increased the amplitude, magnitude and probability of the ASR in combat veterans with PTSD, but did not do so in combat controls. Overall startle was significantly larger in the PTSD subjects; however, this did not account for the differential effect of yohimbine, since yohimbine had no significant effect in the control group. This study demonstrates an excitatory effect of yohimbine on the amplitude, magnitude and probability of the ASR in PTSD patients that is not seen in combat controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Impact of cumulative lifetime trauma and recent stress on current posttraumatic stress disorder symptoms in holocaust survivors.

OBJECTIVE: The purpose of this study was to examine the relationships among cumulative lifetime trauma, recent stressful events, and presence and severity of current posttraumatic stress disorder (PTSD) symptoms in Holocaust survivors and nonexposed comparison subjects. METHOD: Lifetime trauma, recent stressful events, and presence and severity of PTSD were assessed in Holocaust survivors (N=72) and comparison subjects ( N=19). RESULTS: Survivors with PTSD (N =40) reported significantly greater cumulative trauma and recent stress than survivors without PTSD (N=32) and comparison subjects. Severity of PTSD symptoms, cumulative trauma, and recent stress were significantly associated. CONCLUSIONS: The presence and severity of current PTSD were related to having experienced stressful events in addition to the Holocaust.

Aged↗

PubMed1995

Psychological dimensions of depression in borderline personality disorder.

OBJECTIVE: The authors' goal was to test empirically a commonly held assumption that the depression in borderline personality disorder is primarily anaclitic. METHOD: The Depressive Experiences Questionnaire and the Hamilton Rating Scale for Depression were administered to 26 patients with borderline personality disorder (16 of whom were depressed) and 12 depressed patients without borderline personality disorder. RESULTS: Patients with borderline personality disorder showed more self-criticism but did not endorse more anaclitic items than depressed patients without borderline personality disorder. CONCLUSIONS: These findings suggest that self-criticism is an underemphasized characteristic of depression in borderline personality disorder.

Adult↗

PubMed1995

MRI-based measurement of hippocampal volume in patients with combat-related posttraumatic stress disorder.

OBJECTIVE: Studies in nonhuman primates suggest that high levels of cortisol associated with stress have neurotoxic effects on the hippocampus, a brain structure involved in memory. The authors previously showed that patients with combat-related posttraumatic stress disorder (PTSD) had deficits in short-term memory. The purpose of this study was to compare the hippocampal volume of patients with PTSD to that of subjects without psychiatric disorder. METHOD: Magnetic resonance imaging was used to measure the volume of the hippocampus in 26 Vietnam combat veterans with PTSD and 22 comparison subjects selected to be similar to the patients in age, sex, race, years of education, socioeconomic status, body size, and years of alcohol abuse. RESULTS: The PTSD patients had a statistically significant 8% smaller right hippocampal volume relative to that of the comparison subjects, but there was no difference in the volume of other brain regions (caudate and temporal lobe). Deficits in short-term verbal memory as measured with the Wechsler Memory Scale were associated with smaller right hippocampal volume in the PTSD patients only. CONCLUSIONS: These findings are consistent with a smaller right hippocampal volume in PTSD that is associated with functional deficits in verbal memory.

Adult↗

PubMed1995

Low urinary cortisol excretion in Holocaust survivors with posttraumatic stress disorder.

OBJECTIVE: The authors' objective was to compare the urinary cortisol excretion of Holocaust survivors with posttraumatic stress disorder (PTSD) (N = 22) to that of Holocaust survivors without PTSD (N = 25) and comparison subjects not exposed to the Holocaust (N = 15). METHOD: Twenty-four-hour urine samples were collected, and the following day, subjects were evaluated for the presence and severity of past and current PTSD and other psychiatric conditions. RESULTS: Holocaust survivors with PTSD showed significantly lower mean 24-hour urinary cortisol excretion than the two groups of subjects without PTSD. Multiple correlation analysis revealed a significant relationship between cortisol levels and severity of PTSD that was due to a substantial association with scores on the avoidance subscale. CONCLUSIONS: The present findings replicate the authors' previous observation of low urinary cortisol excretion in combat veterans with PTSD and extend these findings to a non-treatment-seeking civilian group. The results also demonstrate that low cortisol levels are associated with PTSD symptoms of a clinically significant nature, rather than occurring as a result of exposure to trauma per se, and that low cortisol levels may persist for decades following exposure to trauma among individuals with chronic PTSD.

Age Factors↗

PubMed1995

Trauma-related symptoms in veterans of Operation Desert Storm: a 2-year follow-up.

OBJECTIVE: This study was a 2-year follow-up in an ongoing prospective examination of development of trauma-related symptoms over time in a community group of veterans of Operation Desert Storm. METHOD: Sixty-two National Guard reservists, from one medical and one military police unit, completed the Mississippi Scale for Combat-Related Posttraumatic Stress Disorder and a DSM-III-R-based posttraumatic stress disorder (PTSD) symptom scale 1 month, 6 months, and 2 years after returning from the Middle East. Differences in symptom severity over time were analyzed by using repeated measure analyses of variance. RESULTS: Scores on the Mississippi scale, but not the DSM-III-R PTSD scale, increased significantly over time. Symptoms of hyperarousal were more severe at all time points than were symptoms of reexperiencing or avoidance. Level of combat exposure, as reflected by the Desert Storm trauma questionnaire, was significantly associated with the score on the Mississippi scale at 2 years but not at 1 month or 6 months. All subjects who met the Mississippi scale's diagnostic criteria for PTSD at 1 or 6 months still met the criteria at 2 years. CONCLUSIONS: Although symptoms were relatively mild, there was an overall increase in PTSD symptoms over 2 years. The statistical relationship between level of combat exposure and PTSD symptoms at 2 years, and not before, suggests that it may take time for the consequences of traumatic exposure to become apparent. Moreover, degree of exposure may be important in predicting the eventual development of symptoms. Continued follow-up will address the evolution of PTSD symptoms in Gulf War veterans.

Female↗

PubMed1994

The concept of the Second Generation program in the treatment of post-traumatic stress disorder among Vietnam veterans.

The concepts of First and Second Generation treatment programs for Vietnam veterans with post-traumatic stress disorder are presented, based on a developmental theoretical model of adaptation. First Generation programs focus on accessing and then working through the effects of the war trauma and aim to diminish the intensity of core PTSD symptoms. Second Generation programs focus on reintegrating veterans into the social context of family and work, and aim to improve their ability to function in society. Both types of treatment may be required in order to help veterans resume their psychological and social development. The need to develop sophisticated models of comprehensive inpatient treatment in order to support scholarly discourse and outcome research is emphasized.

Adaptation, Psychological↗