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Dive into the research topics where Nathan Alkemade is active.

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Featured researches published by Nathan Alkemade.


British Journal of Psychiatry | 2014

Impact of the diagnostic changes to post-traumatic stress disorder for DSM-5 and the proposed changes to ICD-11

Meaghan O'Donnell; Nathan Alkemade; Angela Nickerson; Mark Creamer; Alexander C. McFarlane; Derrick Silove; Richard A. Bryant; David Forbes

BACKGROUND There have been changes to the criteria for diagnosing post-traumatic stress disorder (PTSD) in DSM-5 and changes are proposed for ICD-11. AIMS To investigate the impact of the changes to diagnostic criteria for PTSD in DSM-5 and the proposed changes in ICD-11 using a large multisite trauma-exposed sample and structured clinical interviews. METHOD Randomly selected injury patients admitted to four hospitals were assessed 72 months post trauma (n = 510). Structured clinical interviews for PTSD and major depressive episode, as well as self-report measures of disability and quality of life were administered. RESULTS Current prevalence of PTSD under DSM-5 scoring was not significantly different from DSM-IV (6.7% v. 5.9%, z = 0.53, P = 0.59). However, the ICD-11 prevalence was significantly lower than ICD-10 (3.3% v. 9.0%, z = -3.8, P<0.001). The PTSD current prevalence was significantly higher for DSM-5 than ICD-11 (6.7% v. 3.3%, z = 2.5, P = 0.01). Using ICD-11 tended to show lower rates of comorbidity with depression and a slightly lower association with disability. CONCLUSIONS The diagnostic systems performed in different ways in terms of current prevalence rates and levels of comorbidity with depression, but on other broad key indicators they were relatively similar. There was overlap between those with PTSD diagnosed by ICD-11 and DSM-5 but a substantial portion met one but not the other set of criteria. This represents a challenge for research because the phenotype that is studied may be markedly different according to the diagnostic system used.


Depression and Anxiety | 2014

Utility of the dimensions of anger reactions-5 (DAR-5) scale as a brief anger measure

David Forbes; Nathan Alkemade; Damon Mitchell; Jon D. Elhai; Tony McHugh; Glen W. Bates; Raymond W. Novaco; Richard A. Bryant; Virginia Lewis

Anger is a common emotional sequel in the aftermath of traumatic experience. As it is associated with significant distress and influences recovery, anger requires routine screening and assessment. Most validated measures of anger are too lengthy for inclusion in self‐report batteries or as screening tools. This study examines the psychometric properties of a shortened 5‐item version of the Dimensions of Anger Reactions (DAR), an existing screening tool.


The Journal of Clinical Psychiatry | 2015

Compensation seeking and disability after injury: the role of compensation-related stress and mental health.

Meaghan O'Donnell; Genevieve Meredyth Grant; Nathan Alkemade; Matthew J. Spittal; Mark Creamer; Derrick Silove; Alexander C. McFarlane; Richard A. Bryant; David Forbes; David M. Studdert

OBJECTIVE Claiming for compensation after injury is associated with poor health outcomes. This study examined the degree to which compensation-related stress predicts long-term disability and the mental health factors that contribute to this relationship. METHOD In a longitudinal, multisite cohort study, 332 injury patients (who claimed for compensation) recruited from April 2004 to February 2006 were assessed during hospitalization and at 3 and 72 months after injury. Posttraumatic stress, depression, and anxiety symptoms (using the Mini-International Neuropsychiatric Interview) were assessed at 3 months; compensation-related stress and disability levels (using the World Health Organization Disability Assessment Schedule II) were assessed at 72 months. RESULTS A significant direct relationship was found between levels of compensation-related stress and levels of long-term disability (β = 0.35, P < .001). Three-month posttraumatic stress symptoms had a significant relationship with compensation-related stress (β = 0.29, P < .001) as did 3-month depression symptoms (β = 0.39, P < .001), but 3-month anxiety symptoms did not. A significant indirect relationship was found for posttraumatic stress symptoms and disability via compensation stress (β = 0.099, P = .001) and for depression and disability via compensation stress (β = 0.136, P < .001). CONCLUSIONS Stress associated with seeking compensation is significantly related to long-term disability. Posttraumatic stress and depression symptoms increase the perception of stress associated with the claims process, which in turn is related to higher levels of long-term disability. Early interventions targeting those at risk for compensation-related stress may decrease long-term costs for compensation schemes.


Australian and New Zealand Journal of Psychiatry | 2015

The role of anger and ongoing stressors in mental health following a natural disaster.

David Forbes; Nathan Alkemade; Elizabeth Waters; Lisa Gibbs; Colin Gallagher; Phillipa Pattison; Dean Lusher; Colin MacDougall; Louise Harms; Karen Block; Elyse Snowdon; Connie Kellet; Vikki Sinnott; Greg Ireton; John Richardson; Richard A. Bryant

Objective: Research has established the mental health sequelae following disaster, with studies now focused on understanding factors that mediate these outcomes. This study focused on anger, alcohol, subsequent life stressors and traumatic events as mediators in the development of mental health disorders following the 2009 Black Saturday Bushfires, Australia’s worst natural disaster in over 100 years. Method: This study examined data from 1017 (M = 404, F = 613) adult residents across 25 communities differentially affected by the fires and participating in the Beyond Bushfires research study. Data included measures of fire exposure, posttraumatic stress disorder, depression, alcohol abuse, anger and subsequent major life stressors and traumatic events. Structural equation modeling assessed the influence of factors mediating the effects of fire exposure on mental health outcomes. Results: Three mediation models were tested. The final model recorded excellent fit and observed a direct relationship between disaster exposure and mental health outcomes (b = .192, p < .001) and mediating relationships via Anger (b = .102, p < .001) and Major Life Stressors (b = .128, p < .001). Each gender was compared with multiple group analyses and while the mediation relationships were still significant for both genders, the direct relationship between exposure and outcome was no longer significant for men (p = .069), but remained significant (b = .234, p < .001) for women. Conclusions: Importantly, anger and major life stressors mediate the relationship between disaster exposure and development of mental health problems. The findings have significant implications for the assessment of anger post disaster, the provision of targeted anger-focused interventions and delivery of government and community assistance and support in addressing ongoing stressors in the post-disaster context to minimize subsequent mental health consequences.


The Journal of Clinical Psychiatry | 2016

The long-term psychiatric sequelae of severe injury: a 6-year follow-up study.

Meaghan O'Donnell; Nathan Alkemade; Mark Creamer; Alexander C. McFarlane; Derrick Silove; Richard A. Bryant; David Forbes

OBJECTIVE The impact of mental health on disease burden associated with injury represents a major public health issue, yet almost no information is available on the associated long-term mental health outcomes. The primary aim of this study was to assess the psychiatric outcomes 6 years after a severe injury and their subsequent impact on long-term disability. The secondary aim was to investigate the relationship between a mild traumatic brain injury (mTBI) and long-term psychiatric disorder and its impact on disability. METHODS From April 2004 to February 2006, randomly selected injury patients admitted to 4 hospitals across Australia were assessed during hospitalization and at 72 months after trauma (N = 592). Injury characteristics, the presence of an mTBI (ICD-9 criteria), and previous psychiatric history were assessed during hospitalization. Structured clinical interviews for psychiatric disorders (DSM-IV and DSM-5) and a self-report measure of disability (WHODAS II) were administered at 72 months. RESULTS At 72 months after a severe injury, 28% of patients met criteria for at least 1 psychiatric disorder, with 45% of those presenting with comorbid diagnoses. The most prevalent psychiatric disorder was a major depressive episode (11%) followed by substance use disorder (9%), agoraphobia (9%), posttraumatic stress disorder (6%), and generalized anxiety disorder (6%). The presence of any psychiatric disorder was found to increase the risk for disability (P < .001, odds ratio = 6.04). An mTBI was found to increase the risk for having some anxiety disorders but not to increase disability by itself. CONCLUSIONS The long-term psychiatric consequences of severe injury are substantial and represent a significant contributor to long-term disability. This study points to an important intersection between injury and psychiatric disorder as a leading contributor to disease burden and suggests this growing burden will impose new challenges on health systems.


The Journal of Clinical Psychiatry | 2015

Longitudinal analysis of latent classes of psychopathology and patterns of class migration in survivors of severe injury.

David Forbes; Angela Nickerson; Nathan Alkemade; Richard A. Bryant; Mark Creamer; Derrick Silove; Alexander C. McFarlane; Miranda Van Hooff; Susan Fletcher; Meaghan O’Donnell

OBJECTIVE Little research to date has explored the typologies of psychopathology following trauma, beyond development of particular diagnoses such as posttraumatic stress disorder (PTSD). The objective of this study was to determine the longitudinal patterns of these typologies, especially the movement of persons across clusters of psychopathology. METHOD In this 6-year longitudinal study, 1,167 hospitalized severe injury patients who were recruited between April 2004-February 2006 were analyzed, with repeated measures at baseline, 3 months, 12 months, and 72 months after injury. All patients met the DSM-IV criterion A1 for PTSD. Structured clinical interviews were used to assess psychiatric disorders at each follow-up point. Latent class analysis and latent transition analysis were applied to assess clusters of individuals determined by psychopathology. The Mini International Neuropsychiatric Interview (MINI) and Clinician-Administered PTSD Scale (CAPS) were employed to complete diagnoses. RESULTS Four latent classes were identified at each time point: (1) Alcohol/Depression class (3 months, 2.1%; 12 months, 1.3%; and 72 months, 1.1%), (2) Alcohol class (3 months, 3.3%; 12 months, 3.7%; and 72 months, 5.4%), (3) PTSD/Depression class (3 months, 10.3%; 12 months, 11.5%; and 72 months, 6.4%), and (4) No Disorder class (3 months, 84.2%; 12 months, 83.5%; and 72 months, 87.1%). Latent transition analyses conducted across the 2 transition points (12 months and 72 months) found consistently high levels of stability in the No Disorder class (90.9%, 93.0%, respectively) but lower and reducing levels of consistency in the PTSD/Depression class (81.3%, 46.6%), the Alcohol/Depression class (59.7%, 21.5%), and the Alcohol class (61.0%, 36.5%), demonstrating high levels of between-class migration. CONCLUSIONS Despite the array of psychiatric disorders that may develop following severe injury, a 4-class model best described the data with excellent classification certainty. The high levels of migration across classes indicate a complex pattern of psychopathology expression over time. The findings have considerable implications for tailoring multifocused interventions to class type, as well as flexible stepped care models, and for the potential development and delivery of transdiagnostic interventions targeting underlying mechanisms.


Journal of Traumatic Stress | 2016

Mental Health Following Separation in a Disaster: The Role of Attachment

H. Colin Gallagher; John Richardson; David Forbes; Louise Harms; Lisa Gibbs; Nathan Alkemade; Colin MacDougall; Elizabeth Waters; Karen Block; Dean Lusher; Elyse Baker; Richard A. Bryant

Short-term separation from close family members during a disaster is a highly salient event for those involved. Yet, its subsequent impact on mental health has received little empirical attention. One relevant factor may be attachment style, which influences patterns of support-seeking under threatening conditions. Individuals (N = 914) affected by the 2009 Victorian bushfires in southeastern Australia were assessed for disaster experiences, depression, posttraumatic stress disorder (PTSD) symptoms, and attachment style 3-4 years after the fires. Using multigroup structural equation modelling, individuals who reported separation from close family members during the bushfires (n = 471) were compared to those who reported no separation (n = 443). Cross-sectional results indicated that separated individuals had higher levels of PTSD symptoms. Furthermore, attachment anxiety was more strongly positively associated with depression among separated (b = 0.62) versus not separated individuals (b = 0.32). Unexpectedly, among separated individuals, attachment avoidance had a statistically weaker association with depression (b = 0.17 vs. b = 0.35) and with PTSD symptoms (b = 0.06 vs. b = 0.22). These results suggest that attachment anxiety amplifies a negative reaction to separation; meanwhile, for avoidant individuals, separation in times of danger may facilitate defensive cognitive processes.


Archives of Clinical Neuropsychology | 2015

Scoring Correction for MMPI-2 Hs Scale with Patients Experiencing a Traumatic Brain Injury: A Test of Measurement Invariance

Nathan Alkemade; Stephen C. Bowden; Louis Salzman

It has been suggested that MMPI-2 scoring requires removal of some items when assessing patients after a traumatic brain injury (TBI). Gass (1991. MMPI-2 interpretation and closed head injury: A correction factor. Psychological assessment, 3, 27-31) proposed a correction procedure in line with the hypothesis that MMPI-2 endorsement may be affected by symptoms of TBI. This study assessed the validity of the Gass correction procedure. A sample of patients with a TBI (n = 242), and a random subset of the MMPI-2 normative sample (n = 1,786). The correction procedure implies a failure of measurement invariance across populations. This study examined measurement invariance of one of the MMPI-2 scales (Hs) that includes TBI correction items. A four-factor model of the MMPI-2 Hs items was defined. The factor model was found to meet the criteria for partial measurement invariance. Analysis of the change in sensitivity and specificity values implied by partial measurement invariance failed to indicate significant practical impact of partial invariance. Overall, the results support continued use of all Hs items to assess psychological well-being in patients with TBI.


The Journal of Clinical Psychiatry | 2016

Prediction of late-onset psychiatric disorder in survivors of severe injury: findings of a latent transition analysis

David Forbes; Nathan Alkemade; Angela Nickerson; Richard A. Bryant; Mark Creamer; Derrick Silove; Alexander C. McFarlane; Miranda van Hoof; Andrea Phelps; Susan Rees; Zachary Steele; Meaghan O'Donnell

OBJECTIVE There is a growing body of evidence indicating that late or delayed onset of psychiatric disorder following traumatic injury and other psychological trauma is common. This research, however, has not examined factors that pose risks for delayed development of different types of psychopathology or at different time points. Such research has considerable implications for the development of screening, assessment, and intervention practices. This article investigates risk factors for late-onset disorders up to 72 months after a severe injury. METHODS In this 6-year longitudinal study, 1,167 hospitalized patients with severe injury recruited between April 2004 and February 2006 were analyzed with repeated measures at 3, 12, and 72 months after injury. The Mini-International Neuropsychiatric Interview (MINI) and Clinician-Administered PTSD Scale (CAPS) were employed to complete diagnoses according to DSM-IV. Latent transition analyses with continuous covariates (injury severity, social support, recent life events, and pain) and 1 dichotomous covariate (presence/absence of a psychiatric disorder before injury) were conducted to identify risk factors for transitioning out of a No Disorder class and into one of 3 previously reported psychopathology classes (PTSD [posttraumatic stress disorder]/Depression, Alcohol/Depression, and Alcohol only) between 3 and 12 months (transition 1) and between 12 and 72 months (transition 2) postinjury. RESULTS Movement into the PTSD/Depression class was predicted by injury severity at transitions 1 (P = .003) and 2 (P = .017) and social support (P = .006) at transition 1. Past psychiatric history increased the likelihood of moving into the PTSD/Depression class, with anxiety or mood disorders specifically implicated in transition 1. Movement into the Alcohol/Depression class was predicted by social support at transitions 1 (P = .008) and 2 (P < .001) and also by injury severity (P < .001) and pain (P < .001) at transition 2. Movement into the Alcohol class was predicted only by pain (P = .011) at transition 2. A history of a substance use or alcohol use disorder before injury was implicated in movement into both of the alcohol-based classes. CONCLUSIONS Predictors of developing a delayed-onset psychiatric disorder after severe injury differed by duration after injury and class of disorder. These findings highlight the need to offer targeted screening based on these risk factors to severe injury survivors up to 12 months postinjury, even when they present without disorder at 3 months.


Journal of Anxiety Disorders | 2014

Evaluation of the Dimensions of Anger Reactions-5 (DAR-5) Scale in combat veterans with posttraumatic stress disorder

David Forbes; Nathan Alkemade; Dale Hopcraft; Graeme Hawthorne; Paul O’Halloran; Jon D. Elhai; Tony McHugh; Glen W. Bates; Raymond W. Novaco; Richard A. Bryant; Virginia Lewis

After a traumatic event many people experience problems with anger which not only results in significant distress, but can also impede recovery. As such, there is value to include the assessment of anger in routine post-trauma screening procedures. The Dimensions of Anger Reactions-5 (DAR-5), as a concise measure of anger, was designed to meet such a need, its brevity minimizing the burden on client and practitioner. This study examined the psychometric properties of the DAR-5 with a sample of 163 male veterans diagnosed with Posttraumatic Stress Disorder. The DAR-5 demonstrated internal reliability (α=.86), along with convergent, concurrent and discriminant validity against a variety of established measures (e.g., HADS, PCL, STAXI). Support for the clinical cut-point score of 12 suggested by Forbes et al. (2014, Utility of the dimensions of anger reactions-5 (DAR-5) scale as a brief anger measure. Depression and Anxiety, 31, 166-173) was observed. The results support considering the DAR-5 as a preferred screening and assessment measure of problematic anger.

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David Forbes

University of Melbourne

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Richard A. Bryant

University of New South Wales

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Derrick Silove

University of New South Wales

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Mark Creamer

University of Melbourne

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Angela Nickerson

University of New South Wales

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Zachary Steel

University of New South Wales

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