- Title
- Psychological, functional and olfactory correlates of repeat-violent offenders and their acute responses to sertraline
- Creator
- Challakere Ramaswamy, Vasudeva Murthy
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2024
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Background: Traumatic brain injury (TBI) is a major public health problem associated with numerous behavioural problems, including impulsivity, aggression and violence. TBI can affect the integrity of the orbitofrontal cortex (OFC), a region important for olfaction and behavioural regulation. There is a growing body of literature on olfactory testing to complement conventional assessments in clinical and research practice that is constantly evolving. In this thesis, a systematic review of published studies that reported on the association of olfactory performance with executive functioning was undertaken, followed by a series of papers that examined the association between the olfactory identification (OI) scores and history of TBI and psychological measures in a sample of impulsive violent offenders. The study also aimed to determine changes in psychological correlates following 4 weeks of Sertraline treatment and to determine if the response to SSRIs is influenced by a history of TBI, or olfactory performance in a sample of impulsive violent offenders. Methods: The systematic review was undertaken adopting a standard approach, searching PubMed/MEDLINE, Scopus, EMBASE, Cochrane Library, Web of Science, PsycINFO, and Google Scholar. The study from which the original data were derived was a National Health and Medical research Council-funded randomised controlled trial entitled ‘Reducing impulsive behaviour in repeat violent offenders using a Selective Serotonin Reuptake Inhibitor (ReINVEST)’. The study population consisted of men who were impulsive and violent without major active psychiatric problems whomet a range of additional entry criteria and who underwent a baseline and then repeated assessments with questionnaires targeting impulsivity, mental health, social circumstances, and substance use/abuse over the course of the approximately 12 months of the study. Evidence of past, current and recurrent offending was obtained by record linkage with relevant data bases. After baseline assessments which provided data for studies two and three, all participants underwent a 4 week run-in period during which they were administered sertraline 100mg/d. After 4 weeks on sertraline, all those remaining were randomised to either remain on the sertraline or switched to placebo. A history of past TBI and OI ability using the Sniffin’ Sticks (SS) was assessed, as part of the baseline assessment, before any Selective Seratonin Reuptake Inhbibitors (SSRI) was administered. Results: The systematic review found substantial evidence of associations between olfactory performance and tests associated with frontal lobe testing. The remaining papers were based upon the data recruited as part of the ReINVEST study. Paper two examined correlates of reported past TBI. In the sample of 693 men, 66% were aged 18 and 35, and 55 % reported at least one TBI (‘TBI+’). Compared to TBI- participants (those without a history of TBI), TBI+ participants were more impulsive (Eysenck Impulsivity), irritable, and angry and reported higher levels of assaultive behaviour, depressive symptomology, alcohol use disorder, suicidal ideation, a suicide attempt, and lower quality of life. Potential ‘dose effects’ of TBI severity and frequency of neuropsychiatric symptomatology were identified. Paper Three found that the mean OI scores within the study population were lower than population norms, and 16% of participants were classified as hyposmic. Univariate analyses showed associations of SS scores with age, WIAT scores, impulsivity, TBI and TBI severity, social connectedness, childhood sexual abuse, suicidality and current use of heroin. In multivariate analyses, age, TBI severity and WIAT scores remained significant independent predictors of SS scores (within the normosmic range) or hyposmia (logistic regression). In the fourth paper, following four weeks of sertraline 100 mg/dl significant reductions were observed in BIS impulsivity, EPQ impulsiveness, anger lability, irritability, assault (direct, verbal and indirect assault), psychological distress, depression and substance abuse (alcohol, amphetamine, cannabis, hallucinogen, cocaine, Buprenorphine) relative to baseline (pre-sertraline) assessments, with the greatest reductions for depression (57.4%), psychological distress (45.7%), anger lability (36.7%), indirect assault (32%) and direct assault (29.8%). When the changes of responses in participants with mild TBI (one episode of TBI and LOC < 10 min) were compared with participants without TBI (TBI–), there were greater changes in direct assault (AIAQ) in the mild TBI group relative to the no TBI group, while the no TBI group experienced greater reduction in verbal assault. In linear regression analyses, better performance on the SS was associated with slight reductions in measures of irritability and anger lability and TBI severity was associated with a greater reduction of assault factors ( direct and verbal) and AIAQ total score. Conclusion: In the systematic review, substantial evidence of associations between olfactory performance and tests of executive function and impulsivity was found, albeit not consistently. In the studies of impulsive violent offenders, single and multiple TBIs were common and associations of TBI, TBI severity, and TBI frequency (i.e., TBI ‘burden’) with adverse neuropsychiatric phenomena suggest that TBI may contribute importantly to offender morbidity. Olfactory performance was associated with multiple behavioural phenomena in a pattern that would be consistent with olfactory test results serving as a proxy for orbitofrontal functioning. Olfactory identification scores could predict slight decreases in the in symptoms ( irritability and anger lability scores) relevant to violent offending in impulsive violent offenders. Modest to severe TBI could ‘predict’ better responsiveness in direct, and verbal assault factors and total AIAQ scores. These conclusions are necessarily tentative in light of the significant limitations of the study, including the lack of placebo controls and its short-term nature.
- Subject
- olfaction; traumatic brain injury; orbitofrontal cortex (OFC); violent behaviour; impulsivity; serotonin and sertraline; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1511307
- Identifier
- uon:56481
- Rights
- This thesis is currently under embargo and will be available from 22.07.2025. Copyright 2024 Vasudeva Murthy Challakere Ramaswamy
- Language
- eng
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