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The Police Stress and Health Program // Research
An Update on Research Findings...
We have recently updated a list of the abstracts summaries of the findings thus far and have added links to the full article texts, when available. We hope this information will be helpful to you and your Departments.
The below references have also been categorized to give you a sense of the research timeline.
Should you have any questions about the information provided here or anywhere on this website, please do not hesitate to contact us.
A Note On Our Published ArticlesOur published articles, with a couple of exceptions, can be found on the journal databases PubMed and/or PsycInfo, links to their homepages are below. Unfortunately, due to publication rights, we aren't able to release the full-text versions of our published research on our website. All of the full-text versions are available to view online, most are available by a subscription to their respective website, and some are available free of charge. The direct links have been provided for you in either scenario.
PubMed: http://www.ncbi.nlm.nih.gov/pubmed/
PsycInfo: http://www.apa.org/psycinfo/ (click on "Search PsycInfo Now" on the left)
Click here for a diagram on how to read an article citation.
Role of Routine Work Stress and Critical Incident Exposure in Explaining Posttraumatic Stress in Police Officers
While there has been a great deal of interest in the role of critical incident stress in law enforcement, there has been less attention to the effects of routine work environment stress. We developed the Work Environment Inventory (WEI) to assess exposure to routine work stressors, including negative attitudes of the public and judiciary toward law enforcement, poor physical conditions, ethnic and gender discrimination, and sexual harassment.
In our cross-sectional study of 741 New York and Bay Area officers, exposure to routine work stressors strongly predicted general psychological distress, and was a surprisingly strong predictor of posttraumatic stress symptoms related to officers’ most traumatic career incident.
Our work has focused awareness in law enforcement that efforts to ensure a positive work climate not only improve morale but also hold promise for increasing resilience to critical incidents.
Find this article at Emerald Group Publishing.
Reference Details:
Liberman, A., Best, S., Metzler, T., Fagan, J.A., Weiss, D. and Marmar, C. Routine occupational stress and psychological distress in police. Policing: An International Journal of Police Strategies and Management 2002; 25(2), 421-439.
Terror, Horror and Helplessness During Critical Incidents in Police Officers
Building on the above findings with EMS workers, we next conducted a cross-sectional study of 741 police officers from the New York, Oakland and San Jose Police Departments, and 301 matched controls including both genders. The aim was to determine risk and resilience factors for critical incident related PTSD.
We first focused on the level of terror, horror, helplessness, panic, grief and other experiences of emotional distress at the time of an officer’s self–identified worst duty-related traumatic stressor. The sample included Caucasians, Hispanics and African Americans officers, with oversampling for female and minority officers, exposed to a wide range of critical incidents.
We developed a 13-item self-report measure, the Peritraumatic Distress Inventory (PDI), as a way of obtaining a quantitative measure of the level of distress experienced during and immediately after a traumatic event. The PDI has good reliability and validity. We found that officers with higher scores on the PDI, reflecting greater emotional distress during critical incident exposure, had greater PTSD symptoms.
This finding has immediate practical value for law enforcement. Those officers with high distress, including panic reactions, at the time of critical incident exposure are those in greatest need of immediate psychological support. Immediate care is directed at countering panic by restoring a sense of safety and control.
Those with high levels of emotional distress at the time of critical incident exposure, and in the first 24 to 72 hours after are also the group in greatest need of support and at the same time those that must be approached with the greatest caution when intervening to provide support. They are at risk for adverse effects of debriefing approaches that emphasize emotional retelling of the incident, if exploring raw feelings occurs before the officer has been able to regain emotional composure, they may have the unintended effect of prolonging panic reactions.
In a pilot study of civilian accident victims we have reported that a brief course of an adrenaline blocking medication, propranolol, is promising for controlling immediate panic reactions and reducing PTSD symptoms two months later.
Find this article at PubMed.
Reference Details:
Brunet, A., Weiss, D., Metzler, T., Best, S., Neylan, T., Rogers, C., Fagan, J. & Marmar, C. The Peritraumatic Distress Inventory: a proposed measure of PTSD Criterion A2. Am J Psychiatry 2001; 158(9), 1480-5.
Patterns and Predictors of Sleep Disturbance in Police Officers
Police officers face many stressors that may negatively impact sleep quality. In this data set of 741 New York and Bay Area police officers, we examined the effects of critical incident exposure and routine work environment stressors on sleep quality, controlling for the effects of work shift schedule.
Police officers on both variable and stable day shifts reported significantly worse sleep quality and less average sleep time than civilian control groups. A large percentage of police officers report disturbances in subjective sleep quality. Within police officers, greater critical incident exposure was associated with more nightmares but only weakly associated with generalized insomnia. In contrast, the stress from officers’ general work environment was strongly associated with generalized insomnia.
View the full text of this article free from Psychosomatic Medicine.
Reference Details:
Neylan, T., Metzler, T., Best, S., Weiss, D., Fagan, J., Liberman, A., Rogers, C., Vedantham, K., Brunet, A., Lipsey, T., and Marmar. C. Critical incident exposure and sleep quality in police officers. Psychosom Med 2002; 64(2), 345-52.
Disturbed Sleep Explains Physical Health Problems in Police Officers
Earlier studies with civilian samples demonstrated that chronic sleep disturbances contribute to poor physical health. Posttraumatic stress symptoms have also been associated with increased health problems across numerous studies.
In this sample of 741 New York and Bay Area police officers we found that the relationship between posttraumatic stress symptoms and self-reported physical health problems was explained by sleep problems.
These findings have been helpful to law enforcement by clarifying the types, causes and unexpectedly high rates of sleep disturbances, in an occupation placing high demands on alertness for accurate threat appraisal and rapid reaction times, and by drawing attention to the health risks of chronic sleep disturbances.
View the full text of this article free from Psychosomatic Medicine.
Reference Details:
Mohr, D., Vedantham, K., Neylan, T., Metzler, T., Best, S., and Marmar, C. The mediating effects of sleep in the relationship between traumatic stress and health symptoms in urban police officers. Psychosom Med 2003; 65(3), 485-9.
Role of Gender and Ethnicity in Explaining Posttraumatic Stress in Police Officers
We next assessed for ethnic and gender differences in duty-related symptoms of posttraumatic stress disorder (PTSD) in this sample of 741 New York Police Department (NYPD), Oakland Police Department (OPD) and San Jose Police Department (SJPD) officers.
We found that self-identified Hispanic American officers evidenced greater PTSD symptoms than both self-identified European American and self-identified African American officers. These effects were small in size but they persisted even after controlling for differences in other relevant variables. We found no gender differences in PTSD symptoms.
Our findings are of note because: (a) they replicate a previous finding of greater PTSD among Hispanic American military personnel and (b) they fail to replicate the typical finding of greater rates of PTSD symptoms among women in the community. Female police officers are as highly exposed to critical incidents and as resilient as their male colleagues.
Find this article at PubMed.
Reference Details:
Pole, N., Best, S., Weiss, D., Metzler, T., Liberman, A., Fagan, J., Marmar, C. Effects of gender and ethnicity on duty-related posttraumatic stress symptoms among urban police officers. J Nerv Ment Dis. 2001; 189(7), 442-8.
In an attempt to further understand the role of Hispanic ethnicity in vulnerability to PTSD, we identified predictors of PTSD symptom severity that distinguished Hispanic police officers (n = 189) from their non-Hispanic Caucasian (n = 317) and Black (n = 162) counterparts and modeled them to explain the elevated Hispanic risk for PTSD.
We found that greater peritraumatic dissociation, greater wishful thinking and self-blame coping, lower social support, and greater perceived racism were important variables in explaining the elevated risk for PTSD symptom severity among Hispanic officers.
These results may be important for prevention of PTSD in a rapidly growing ethnic group in law enforcement.
View the full text of this article free from the American Psychological Association.
Reference Details:
Pole, N., Best, S.R., Metzler, T., & Marmar, C.R. (2005). Why Are Hispanics at Greater Risk for PTSD? Cultural Diversity and Ethnic Minority Psychology; 11(2), 144-161.
Police Officers with PTSD Symptoms Have Greater Acoustic Startle Reactions
More recently, our work has focused on biological factors associated with vulnerability and resilience to posttraumatic stress disorder. We initially established a laboratory in San Francisco to acquire heart rate, skin conductance, muscle tone, and salivary stress hormones including adrenaline and cortisol.
We have measured biological responses of police officers after critical incident exposure to loud startling tones and academy recruits prior to critical incident exposure to startling tones and vivid portrayals of real life critical incidents, and in both groups measured awakening cortisol before and after administering a synthetic steroid.
We first studied responses to startling sounds under low, medium, and high threat conditions in 55 Bay Area police officers who reported a range of PTSD symptoms. Greater PTSD symptom severity was related to greater physiologic responses to startling tones under conditions of ambiguous threat.
Find this article at PubMed.
Reference Details:
Pole, N., Neylan, T., Best, S., Orr, S., & Marmar, C. Fear-potentiated startle and posttraumatic stress symptoms in urban police officers. Journal of Traumatic Stress 2003; 16(5), 471-479.
We also found that lower levels of cortisol on awakening were related to greater PTSD symptoms.
Our results are of value to law enforcement by contributing to the search for objective biological markers of posttraumatic stress in greater eye blink and skin conductance reactions to loud tones and in lower levels of salivary cortisol on awakening. As theses biological markers are refined, they hold promise for understanding who is at risk for PTSD, informing new treatments and adjudicating disability claims.
Find this article at PubMed.
Reference Details:
Neylan, T.C., Brunet, A., Pole, N., Best, S.R., Metzler, T.J., Yehuda, R., & Marmar, C.R. (2005). PTSD symptoms predict waking salivary cortisol levels in police officers. Psychoneuroendocrinology; 30, 373-381.
The Role of Childhood Trauma in Explaining Stress Reactivity Of Police Academy Recruits
We have recently initiated a prospective study of 500 New York and Bay Area police academy recruits, who will be assessed during training and followed for the first two years of police service.
We have expanded our biological research with laboratories in New York and San Francisco, both assessing heart rate, skin conductance, eyeblink response, salivary stress hormones including adrenaline and cortisol, diurnal sleep patterns and reaction times. We have established control systems in San Francisco, utilizing internet resources to maintain real time calibration, for managing biological and clinical assessments in New York. We have manualized the control procedures, establishing a process that can be replicated in London and elsewhere.
The primary aim of this study is to determine biological and behavioral predictors of resilience and vulnerability to critical incident stress prior to critical incident exposure. Along with twin studies, prospective studies are the strongest designs to clarify if abnormalities in PTSD are a result of exposure or are vulnerabilities that are heritable or the product of early life experience.
First results from our prospective study focus on 76 male and female police academy recruits, average age 28 years, exposed to a 20 minute video depicting real-life officers exposed to highly stressful incidents. Salivary cortisol and an adrenaline metabolite were collected at baseline, immediately after the video, and twenty minutes after the video. Childhood trauma prior to age 14 was assessed with the Life Stressor Checklist.
Police academy recruits with childhood trauma histories had an increased adrenaline response to psychological stress
Find this article at the Society for Biological Psychiatry.
Reference Details:
Otte, C., Neylan, T.C., Pole, N., Metzler, T., Best, S., Henn-Haase, C., Yehuda, R., & Marmar, C.R. (2005). Association Between Childhood Trauma and Catecholamine Response to Psychological Stress in Police Academy Recruits. Society of Biological Psychiatry; 57, 27-32.
We then looked at the association between childhood trauma and physiological stress response. We exposed 90 police cadets to startling sounds, under threat of shock, while assessing their heart rate (HR), skin conductance (SC), eyeblink electromyogram (EMG), and danger/safety emotion responses.
When compared to their unexposed counterparts (n = 65), cadets with childhood trauma (n = 25) produced higher EMG and SC responses, and threat-dependent elevations in reported negative emotions.
Results suggest that childhood trauma may lead to long-lasting alterations in emotional psychophysiological reactivity.
Find this article at PubMed.
Reference Details:
Pole, N., Neylan, T.C., Otte, C., Metzler, T.J., Best, S.R., Henn-Haase, C., & Marmar, C.R. (2007). Associations Between Childhood Trauma and Emotion-Modulated Psychophysiological Responses to Startling Sounds: A Study of Police Cadets. Journal of Abnormal Psychology; 116(2), 352-361.
Alexithymia and PTSD Symptoms in Urban Police Officers
We examined the relationship between alexithymia and PTSD both cross-sectionally and prospectively. 166 urban police officers were surveyed between 1998 and 1999 and prospectively in 54 of these officers who participated in a follow-up survey after the September 11, 2001 (9/11) terrorist attacks. In cross-sectional analyses, alexithymia scores were positively associated with PTSD symptom levels and self-reported childhood emotional abuse.
In prospective analyses, alexithymia scores significantly predicted 9/11-related PTSD symptom severity over and above pre-9/11 PTSD symptoms.
Find this article at PubMed.
Reference Details:
McCaslin, S.E., Metzler, T.J., Best, S.R., Liberman, A., Weiss, D.S., Fagan, J., & Marmar, C.R. (2005). Alexithymia and PTSD Symptoms in Urban Police Officers: Cross-Sectional and Prospective Findings. Journal of Traumatic Stress, 19(3), 361-373.
Impact of Personal Threat on Police Officers' Responses to Critical Incident Stressors
We examined the relationship between type of critical incident (CI) stressor and peritraumatic responses and posttraumatic stress disorder symptoms in police officers. 662 Officers provided narratives of their most distressing CI experienced during police service and completed measures of related peritraumatic responses and PTSD symptoms.
Classification of the primary narrative fell into five categories: personal life threat, duty-related violence, encountering physical or sexual assault victims, exposure to civilian death, or other). Results suggest that critical incidents involving greater personal threat may place an officer at greater risk for subsequent distress.
Find this article at PubMed.
Reference Details:
McCaslin, S.E., Rogers, C.E., Metzler, T.J., Best, S.R., Weiss, D.S., Fagan, J.A., Liberman, A., & Marmar, C.R. (2006). The Impact of Personal Threat on Police Officers' Responses to Critical Incident Stressors. The Journal of Nervous and Mental Disease; 194(8), 591-597.
One group deeply impacted by the World Trade Center Attacks was the New York Police Department. The uniquely traumatic circumstances of the attacks and subsequent recovery operations occurred against a background of high levels of ongoing routine work environment and critical incident stressors, including threats of future terrorist attacks.
We conducted a prospective cohort study of New York police officers, surveying 541 from our sample of 741 approximately a year and half before 9/11, and reassessing 301 of these officers a year and a half after 9/11.
Prior to 9/11, 3.5% of NYPD officers were estimated to have PTSD and 3.5 % partial PTSD; this compares with 8.8% with PTSD and 15.0% with partial PTSD after 9/11. Compared to pre 9/11, NYPD officers were also found to have increases in anxiety, depression, sleep disturbances, and marital adjustment problems.
The strongest predictors of 9/11 related PTSD symptoms were greater PTSD symptoms prior to 9/11, greater dissociation and emotional distress during 9/11 exposure, and both greater negative life events and lower social support after 9/11.
Our findings represent the only available data on law enforcement before and after a large scale terrorist attack, and reveal a large and lasting increase in PTSD symptoms.
Reference Details:
C.R. Marmar, T. Metzler, C. Chemtob, K. Delucchi, A.Liberman, J. Fagan, D. S. Weiss, D. Mohr , T. Neylan M.D., & S. Best. Impact of the World Trade Center Attacks on the New York City Police Department: A Prospective Study, Presentation Only.
Association Between Alexithymia and Neuroendocrine Response to Psycholgical Stress in Police Academy Recruits
Alexithymia has been associated with both posttraumatic stress disorder and neuroendocrine responses to stress. This study examined the relationship of alexithymia to salivary cortisol and 3-methoxy-4-hydroxy-phenyglycol (MHPG) in a sample of police academy recruits exposed to a video stress challenge. Alexithymia scores were negatively associated with catecholamine response to the video challenge but no association was found between alexithymia scores and cortisol reactivity.
Find this article at Pubmed .
Reference Details:
McCaslin, S.E., Inslicht, S.S., Neylan, T.C., Metzler, T.J., Otte, C., Lenoci, M., Henn-Haase, C., Best, S., & Marmar, C.R.(2006). Association Between Alexithymia and Neuroendocrine Response to Psychological Stress in Police Academy Recruits. Annals of the New York Academy of Sciences ;1071, 425-427.
A Prospective Study of Trait Anger and PTSD Symptoms in Police
It is unknown whether anger is a risk factor for the development of posttraumatic stress disorder (PTSD) symptoms, arises as a consequence of PTSD, or both.
Two hypotheses were tested in 180 police recruits: Greater trait anger during training will predict greater PTSD symptoms at one year; greater PTSD symptoms at one year will predict greater state anger at one year. Both hypotheses were confirmed, suggesting that trait anger is a risk factor for PTSD symptoms, but that PTSD symptoms are also associated with an increase of state anger. Increased anger is important not only because of the impact it has on individual distress and physical health, but also because of its potential public health impact.
Find this article at Pubmed .
Reference Details:
Meffert, S.M., Metzler, T.J., Henn-Haase, C., McCaslin, S., Inslicht, S., Chemtob, C., Neylan, T., Marmar, C.R. (2008). A Prospective Study of Trait Anger and PTSD Symptoms in Police.The Journal of Traumatic Stress ;21(4), 410-416.
Trait Dissociation Predicts PTSD Symptoms in Urban Police Officers
The current study prospectively examines the predictive relationship of trait dissociation, assessed during academy training, to PTSD symptoms assessed at 12 months of active police duty in relatively young and healthy police academy recruits (N=180). The roles of pre-academy trauma exposure, exposure to life-threatening critical incidents during police duty, and peritraumatic dissociation at the time of the officer's worst critical incident were also examined.
Utilizing path analytic techniques, greater trait dissociation, assessed during academy training, was predicitive of both peritraumatic association, and PTSD symptoms assessed at 12 months of police service. Moreover, after accounting for trait dissocation and peritraumatic dissociation, the relationship of previous trauma to later PTSD symptoms was no longer significant, demonstrating that the effect of previous trauma on later vulnerability to PTSD symptoms in this sample may be mediated by both trait and peritraumatic dissociation.
Find this article at Pubmed .
Reference Details:
McCaslin, S.E., Inslicht, S.S., Metzler, T.J., Henn-Haase, C., Maguen, S., Beylan, T.C., Choucroun, G., & Marmar, C.R. (2008). Trait Dissociation Predicts PTSD Symptoms in a Prospective Study of Urban Police Officers.The Journal of Nervous and Mental Disease ; 196(12), 912-918.
Prediction of PTSD Symptoms Using Fear Potentiated Auditory Startle Responses
Posttraumatic stress disorder (PTSD) has been most consistently associated with exaggerated physiologic reactivity to startling sounds when such sounds occur in threatening contexts. There is conflicting evidence about weather startle hyperreactivity is a preexisting vulnerability factor for PTSD or an acquired result of posttrauma neural sensitization. Until now, there have been no prospective studies of physiologic reactivity to startling sounds in threatening contexts as predictors of PTSD symptoms.
One hundred and thirty-eight police academy cadets without current psychopathology were exposed to repeated 106-dB startling sounds under increasing (low, medium, or high) threat to mild electric shock while their eye-blink electromyogram, skin conductance, heart rate, and subjective fear responses were recorded. Measures of response habituation were also calculated. Following 1 year of exposure to police-related trauma, these participants were assessed for PTSD symptom severity.
After accounting for other baseline variables that were predictive of PTSD symptom severity (age and general psychiatric distress), more severe PTSD symptoms were prospectively and independently predicted by the following startle measures: greater subjective fear under low threat, greater skin conductance under high threat, and slower skin conductance habituation.
These results imply that hypersensitivity to contextual threat (indexed by greater fear under low threat), elevated sympathetic nervous system reactivity to explicit threat (indexed by larger responses under high threat), and failure to adapt to repeated aversive stimuli (evidenced by slower habituation) are all unique preexisiting vulnerability factors for greater PTSD symptom severity following traumatic stress exposure. These measures may eventually prove useful for preventing PTSD.
Find this article at Pubmed .
Reference Details:
Pole, N., Neylan, T.C., Otte, C., Henn-Haase, C., Metzler, T.J., Marmar, C.R. (2009). Prospective Prediction of Posttraumatic Stress Disorder Symptoms Using Fear Potentiated Auditory Startle Responses. Biological Psychiatry; 65(3), 235-240.
Routine Work Environment Stress and PTSD Symptoms in Police Officers
This study examined the relationship between routine work environment and Posttraumatic Stress Disorder (PTSD) symptoms in a sample of police officers (N=180) who were first assessed during academy training and reassessed one year later.
In a model that included gender, ethnicity, traumatic exposure prior to entering the academy, current negative life events, and critical incident exposure over the last year, routine work environment stress was most strongly associated with PTSD symptoms. We also found that routine work environment stress mediated the relationship between critical incident exposure and PTSD symptoms and between current negative life events and PTSD symptoms.
Ensuring that the work environment is functioning optimally protects against the effects of off-duty critical incidents and negative life events outside police service.
Reference Details:
Maguen, S., Metzler, T.J., McCaslin, S.E., Inslicht, S., Henn-Haase, C., Neylan, T.C., & Marmar, C.R. (In press). Routine Work Environment Stress and PTSD Symptoms in Police Officers. Journal of Nervous and Mental Disease.
Predictors of Depression Symptoms in Police
Police work is one of the most stressful occupations. Previous research has indicated that work stress and trauma exposure may place individuals at heightened risk for the development of depression symptomatology.
This prospective longitudinal study was designed to examine predictors of depression symptoms in police service. 119 healthy police recruits from an ongoing prospective study were examined. Participants completed baseline measures of depression symptoms, childhood trauma exposure, neuroticism, and self-worth during academy training. Follow-up measures of depression symptoms, PTSD symptoms, critical incident exposure, negative life effects, and routine work environment stress were assessed after 12 months of police service.
Hierarchical linear regression analysis was conducted to examine predictors of current levels of depression symptoms, controlling for baseline depression symptoms and current PTSD symptoms. Greater childhood trauma exposure, lower self-worth during training and greater perceived work stress in the first year of police service predicted greater depression symptoms at 12 months. Depression symptoms at one year of police service were partly independent from PTSD symptoms at 12 months. Greater childhood trauma exposure and lower self-worth during training may be important variables to screen as risk factors for duty-related depression. Strategies to reduce routine work environment stress have potential to decrease duty-related depression in law enforcement.
Reference Details:
Wang, Z., Inslicht, S.S., Metzler, T.J., Henn-Haase, C., McCaslin, S.E., Tong, H., & Marmar, C.R. (In press). A Prospective Study of Predictors of Depression Sympoms in Police. Journal of Psychiatry Research.
Family Psychiatric History, Peritraumatic Reactivity, and Posttraumatic Stress Symptoms
Family history of psychiatric and substance use disorders has been associated with posttraumatic stress disorder (PTSD) in cross-sectional studies. Using a prospective design, we examined the relationships of family history of psychiatric and substance use disorders to posttraumatic stress symptoms in 278 healthy police recruits.
During academy training, recruits were interviewed on family and personal psychopathology, prior cumulative civilian trauma exposure, and completed self-report questionnaires on nonspecific symptoms of distress and alcohol use. Twelve months after commencement of active duty, participants completed questionnaires on critical incident exposure over the previous year, peritraumatic distress to the worst critical incident during this time, and posttraumatic stress symptoms.
A path model indicated: 1) family loading for mood and anxiety disorders had an indirect effect on posttraumatic stress symptoms at 12 months that was mediated through peritraumatic distress to the officer's self-identified worst critical incident; 2) family loading for substance use disorders also predicted posttraumatic stress symptoms at 12 months and this relationship was mediated through peritraumatic distress.
These findings support a model in which family histories of psychopathology and substance abuse are pre-exisiting vulnerability factors for experiencing greater peritraumatic distress to critical incident exposure which, in turn, increases the risk for development of symptoms of posttraumatic stress disorder. Replication in other first responders, military and civilains will be important to determine generalizability of these findings.
Reference Details:
Inslicht, S.I., McCaslin, S.E., Metzler, T.J., Henn-Haase, C., Hart, S.L., Maguen, S., Neylan, T.C., Marmar, C.R. (In press). Family Psychiatric History, Peritraumatic Reactivity, and Posttraumatic Stress Symptoms: A Prospective Study of Police.Journal of Psychiatric Research.
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