Omar M Alhassoon

Omar M Alhassoon
California School of Professional Psychology · Department of Clinical Psychology

PhD

About

66
Publications
18,761
Reads
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1,747
Citations
Additional affiliations
August 2016 - present
California School of Professional Psychology
Position
  • Professor
August 2016 - present
University of California, San Diego
Position
  • Researcher
August 2011 - July 2016
California School of Professional Psychology
Position
  • Professor (Associate)

Publications

Publications (66)
Article
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Background: Diffusion tensor imaging has been used to explore white matter changes in heroin-dependent patients; however, results have been inconsistent. Objectives: The current study meta-analytically examines the neuroimaging findings of all studies published before 2014 using the novel technique of Effect Size Signed Differential Mapping (ES-...
Article
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Previous neuroimaging studies of recently detoxified alcohol-dependent patients (RDA) have found significant loss of white matter integrity associated with the shrinkage of the frontal lobes and thinning of the corpus callosum, especially the genu. The current study hypothesized that, in addition to exhibiting the most microstructural white matter...
Article
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Voxel-based morphometry has been used to explore gray matter alterations in cocaine and methamphetamine dependence. However, the results of this research are inconsistent. The current study meta-analytically examined neuroimaging findings of all studies published before 2014 using the Anisotropic Effect-Size Signed Differential Mapping (ES-SDM). In...
Article
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Background In mental health, comorbidities are the norm rather than the exception. However, current meta-analytic methods for summarizing the neural correlates of mental disorders do not consider comorbidities, reducing them to a source of noise and bias rather than benefitting from their valuable information. Objectives We describe and validate a...
Article
Objective A previous meta-analysis assessing the impact of heart failure (HF) on cognition found the HF group performed more poorly than the healthy control (HC) on global cognition measures. The study observed a medium effect and moderate heterogeneity when using the Mini-Mental Status Examination (MMSE) to measure HF’s impact on global cognition....
Article
Objective A previous meta-analysis utilized the Trail Making Test A (TMT-A) to measure the impact of heart failure (HF) on attention. A near medium effect size with moderate heterogeneity was observed, the HF group performed worse than healthy controls (HC). This study explores if the age of the HF group moderates differences in the performance of...
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Due to the lack of research on the adverse impact of acculturative stress on the mental health, the current study examined the associations between acculturative stress and post-migration mental health outcomes among 219 Iraqi refugee women resettled in San Diego, California. Mental illness, trauma history, and acculturative stress were measured an...
Article
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A variety of neuropsychological changes secondary to heart failure have been documented in the literature. However, what remains unclear are which neuropsychological abilities are the most impacted by heart failure and what tests have the sensitivity to measure that impact. Eight databases were searched for articles that examined the neuropsycholog...
Poster
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Previous research has found executive dysfunction in patients with heart failure (HF); however, the specific impact of HF on the subdomain of inhibition remains unclear. This study serves to meta-analytically examine the performance on tasks of inhibition in adults with a diagnosis of HF and identify which tests are more sensitive to detect impairm...
Poster
Cognitive flexibility, a sub-domain of executive functioning, requires individuals to have intact attention, processing speed, and working memory to inhibit prepotent responses (Suchy, 2015). There is some evidence that heart failure (HF) can impact cognitive flexibility and might have significant practical implications on patients’ lifestyle adjus...
Poster
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Snapshot • This meta-analysis examined the effect of heroin on attention by analyzing data using digit span forward (DS) and continuous performance test (CPT). • We examined whether DS or CPT differ in their ability to detect the impact of the drug. • Heroin-dependent individuals performed similarly on both of these tests with an estimated average...
Poster
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Objective The Category Test (CT) has consistently been found to be sensitive at detecting the effects of alcohol on the brain. However, this test has not been as widely used in examining the effects of methamphetamine. The current meta-analysis compared effect sizes of studies that have examined performance on the CT in alcohol versus methamphetami...
Article
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Objective Research suggests that cocaine and methamphetamine differ in their impact on executive functions (EF). The Paced Auditory Serial Addition Test (PASAT) is used to assess working memory; a component of EF. The purpose of this meta-analysis was to examine the difference between the effect of these two drugs on PASAT scores. Data Selection T...
Article
Objective Poor inhibitory control is a characteristic of Alcohol Use Disorder (AUD) that might be associated with worse treatment outcomes because of its contribution to the likelihood of relapse. One valid and efficient tool to examine inhibitory control is the Stroop Color-Word Interference Test (Stroop inhibition). The purpose of this meta-analy...
Article
Objective Heroin dependent individuals appear to have significant deficits in attention which can be assessed using digit span forward (DSF) or the continuous performance test (CPT). The current meta-analysis examined differences between DSF and CPT results in studies of heroin dependent participants. Data selection Two researchers independently s...
Article
Objective Late-life depression (LLD) has been associated with cognitive impairments in domains such as memory, processing speed, and executive functions (e.g., initiation). However, it is unclear whether or not LLD is associated with language fluency difficulties that are often seen in some forms of dementia. Broadly, letter fluency is often observ...
Article
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Background: Research has demonstrated that patients with opioid use disorders (OUD; including both opioid abuse and/or dependence) have poorer neuropsychological functioning compared to healthy controls; however, the pattern and robustness of the findings remain unknown. Objectives: This study meta-analyzed the results from previous research examin...
Poster
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v This meta-analytical study explores the performance of Wisconsin Card Sorting Test (WCST) in individuals with cocaine versus methamphetamine dependence. The differences in performance were analyzed using 15 relevant studies using the Comprehensive Meta-analysis (CMA) software. Results showed that methamphetamine users performed worse on number of...
Article
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Background: Transphobia studies have typically relied on self-report measures from heterosexual samples. However, there is evidence suggesting the need to use indirect measures and to explore transphobia among other populations. Aims: This study examined how explicit and implicit attitudes toward transwomen and transmen differ between people of di...
Article
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Background: Previous meta-analytical research examining cocaine and methamphetamine separately suggests potentially different neuropsychological profiles associated with each drug. In addition, neuroimaging studies point to distinct structural changes that might underlie differences in neuropsychological functioning. Objectives: This meta-analys...
Article
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The purpose of this study was to develop and validate 2 gender identity implicit association tests (GI-IATs) designed to assess attitudes toward transsexual men (Transmen-IAT) and transsexual women (Transwomen-IAT). A sample of 344 Mechanical Turk participants from the United States (173 women, 129 men, 43 transgender) completed the following: GI-I...
Article
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Background: Prior research utilizing whole-brain neuroimaging techniques has identified structural differences in gray matter in opioid-dependent individuals. However, the results have been inconsistent. Objectives: The current study meta-analytically examines the neuroimaging findings of studies published before 2016 comparing opioid-dependent...
Article
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Background: Promising models for cognitive rehabilitation in alcohol treatment rest on a more nuanced understanding of the associated impairments in the multifaceted domains of executive functioning (EF) and impulsivity. Objectives: This meta-analysis examined the effects of alcohol on the individual subcomponents of EF and impulsivity in recent...
Poster
Background: Neuropsychology has recently focused on understanding potential evidence-based enhancers and modulators of neurocognitive performance. The Neurovisceral Integration Model proposes that the reciprocity between autonomic and central nervous systems facilitates an individual’s ability to respond appropriately to cognitive and other demands...
Poster
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The Neurovisceral Integration Model proposes that the reciprocity between autonomic and central nervous systems facilitates an individual’s ability to respond appropriately to environmental demands by proper vagal withdrawal and recovery. Resting Heart Rate Variability has been shown to be associated with performance on tasks involving executive fu...
Poster
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Recent research has shown vagal-related indices to be differentially associated with exercise at varying intensities, particularly moderate and strenuous intensity. However, little is known about the relationship between regular exercise and vagal withdrawal and recovery, potential markers of physiological resilience. The purpose of this study is t...
Article
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Background: Because of their ability to reach a much wider audience than face-to-face counseling or psychoeducation, computer-delivered interventions for risky or potentially problematic use have been increasing on college campuses. However, there are very few studies that examine who benefits most from such interventions. Objectives: The purpos...
Article
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Advances in clinical research have led to significant alterations in diagnostic criteria for alcohol-use disorders (AUD). Neuroimaging techniques are now being called upon to shed light on the validity and clinical utility of diagnostic criteria. For example, craving has recently been added to the diagnostic criteria of AUD based mainly on neurobio...
Poster
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The Neurovisceral Integration Model proposes that the reciprocity between the autonomic and central nervous systems facilitates an individual’s ability to respond appropriately to environmental demands by proper vagal withdrawal and recovery. Neuroimaging studies have shown the prefrontal cortex to be significantly associated with Heart Rate Variab...
Poster
Full-text available
High levels of trait anxiety (TA) as measured by the State-Trait Anxiety Inventory (STAI) have consistently been shown to be associated with low cardiac vagal control. While the current literature illustrates that TA is associated with reduced autonomic regulation; dynamic measures of vagal activity as assessed by vagal withdrawal and recovery in r...
Article
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The number of older adults with alcohol use disorder (AUD) is expected to significantly increase in the coming years. Both aging and AUD have been associated with compromised white matter microstructure, although the extent of combined AUD and aging effects is unclear. This study investigated interactions between aging and AUD in cerebral white mat...
Article
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High levels of trauma-related psychological distress have been documented among ethnically diverse refugees. As the number of refugees worldwide continues to grow, determining the efficacy of established methods of trauma-focused therapy for this population is crucial. This meta-analysis examined the results of randomized controlled trials of psych...
Article
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Few studies have examined the effects of total sleep deprivation (TSD) on cognitive performance and brain activation using functional MRI (fMRI) in older adults. The current study examines blood oxygen level-dependent (BOLD) activation in older adults and younger adults during the sustained attention (GO) and response inhibition (NOGO) portions of...
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The attitudes of 124 heterosexual college students were measured using the Attitudes Regarding Bisexuality Scale before and after reading a factual excerpt on bisexuality, an autobiographical excerpt of a bisexual woman, or an article unrelated to bisexuality. Tolerance toward bisexuality and the belief in the stability of bisexuality were assessed...
Article
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A number of researchers have argued for the existence of different subtypes of posttraumatic stress disorder (PTSD). In the current paper we present criteria by which to assess these putative subtypes, clarify potential pitfalls of the statistical methods employed to determine them, and propose alternative methods for such determinations. Specifica...
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Approximately half of those infected with the human immunodeficiency virus (HIV) exhibit cognitive impairment, which has been related to cerebral white matter damage. Despite the effectiveness of antiretroviral treatment, cognitive impairment remains common even in individuals with undetectable viral loads. One explanation for this may be subtherap...
Article
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Background: TEMPS-A (Temperament Evaluation of the Memphis, Pisa, Paris and San Diego - Autoquestionnaire) is a new self-assessed temperament 110-item scale with depressive (D), cyclothymic (C), hyperthymic (H), irritable (I) and anxious (A) subscales. To date, it has been translated into 25 languages, and validated in 10. The present Hungarian ve...
Article
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Human immunodeficiency virus (HIV) and methamphetamine (METH) use disorders are associated with cerebral dysfunction. To determine whether these effects were evident on in vivo neuroimaging, quantitative, single voxel magnetic resonance (MR) spectroscopy was used to assess frontal white matter, frontal gray matter, and basal ganglia in 40 HIV+/METH...
Article
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Nucleoside reverse transcriptase inhibitors (NRTIs) suppress human immunodeficiency virus (HIV) replication, but are often associated with mitochondrial toxicity. Although well studied outside of the central nervous system, no investigation has examined the effects of these drugs on brain mitochondria of individuals living with HIV. The authors use...
Article
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Proton magnetic resonance spectroscopy was used to evaluate gender influences on alcohol-associated changes in brain metabolism. Concentrations of N-acetylaspartate, choline-containing compounds, myo-inositol, and creatine plus phosphocreatine in frontal lobe gray matter and white matter were estimated in eight women and 17 men who were recently de...
Article
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Although abuse of cocaine or methamphetamine usually takes place in the context of heavy drinking, there is little information on the effects of such substance use comorbidity on brain perfusion. We explored similarities and differences in the effects of these two drugs in combination with alcohol on brain function using SPECT. Global and regional...
Article
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Investigations have suggested that frontal lobe abnormalities are a prominent feature of the alcoholic brain, indicated by impaired neuropsychological performance on tests of frontal lobe function and by reduced frontal lobe volume in neuroimaging and neuropathological examinations. White matter compartment volume loss may underlie observed brain s...
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The following is a correction for an error that occurred in the Journal of the International Neuropsychological Society, Vol. 6, No. 3 . The error occurred in the article titled “Personality change disorder in children and adolescents following traumatic brain injury,” pp. 279–289, by Max et al. On page 285, under the subheading “Injury Factors,” b...
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Individuals in short-term abstinence from chronic alcohol consumption commonly have neuropsychological impairments with parallel abnormalities in brain structure. Stable, long-term sobriety often results in improvements in both brain structure and function, although the mechanisms underlying these changes are currently not well understood. To inves...
Article
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HIV infection and abuse of central nervous system (CNS) stimulants are both associated with brain damage and dysfunction. CNS stimulant overdose can lead to microinfarction, hemorrhagic lesions, and vasculitis (Bostwick, 1981; Cahill et al., 1981), and may impact frontostriatal systems. Investigations of HIV-infected (HIV+) individuals have de...
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HIV infection often results in neuropsychological (NP) impairment. In order to assess the impact that HIV-related NP deficits may have on automobile driving, we evaluated 68 HIV-seropositive drivers using an NP battery and two PC-based driving simulations. Thirty-two participants were classified as NP impaired; most (72%) evidenced only mild impair...
Article
Full-text available
HIV infection often results in neuropsychological (NP) impairment. In order to assess the impact that HIV-related NP deficits may have on automobile driving, we evaluated 68 HIV-seropositive drivers using an NP battery and two PC-based driving simulations. Thirty-two participants were classified as NP impaired; most (72%) evidenced only mild...