Predictors Of Response To Antidepressants: Utility Of Behavioural, Neuroimaging And Genetics Data
Funder
National Health and Medical Research Council
Funding Amount
$310,071.00
Summary
Major depressive disorder (MDD) is projected to cause the second greatest global burden of disease by 2020, highlighting the urgent need for valid predictors of effective treatment response. Currently, there are no accurate predictors of response to antidepressants in MDD, and successful treatment relies greatly on 'trial and error'. This process is demanding on health resources, and may be a factor in the high suicide rates in depressed patients. Previous research on treatment response has been ....Major depressive disorder (MDD) is projected to cause the second greatest global burden of disease by 2020, highlighting the urgent need for valid predictors of effective treatment response. Currently, there are no accurate predictors of response to antidepressants in MDD, and successful treatment relies greatly on 'trial and error'. This process is demanding on health resources, and may be a factor in the high suicide rates in depressed patients. Previous research on treatment response has been limited by recruitment of small, heterogeneous patient samples, lack of placebo control, and a failure to examine task related activity in brain imaging studies. Perhaps one of the more troubling aspects of research that aims to predict treatment response to antidepressant medications is the use of commonly used outcome measures such as the Hamilton Rating Depression Scale (HAM-D), which were developed long before current classification systems of depression came into use. The US Federal Drug Administration has recently identified what they call a translational gap such that behavioural and biological measures are the most robust for detection of disorders such as depression, yet these measures remain to be translated into clinical tools that can be used to evaluate treatment. The aim of the current study therefore is to determine whether genetic variability is related to treatment outcome as defined by a more objective outcome measure (facial expression perception) using a randomised controlled design. The study will also determine whether brain measures (fMRI, EEG) enhance the prediction of SSRI response to both clinical and behavioural measures, over and above the genetic contribution.Read moreRead less
The Effect Of Stress And Hypercortisolaemia On Limbic Epileptogenesis & Affective Disorder.
Funder
National Health and Medical Research Council
Funding Amount
$380,714.00
Summary
This project has the potential to provide novel insights about the causal connections between stress, psychiatric illness (specifically anxiety and depression) and temporal lobe epilepsy (TLE) - the most common form of medical refractory epilepsy in the community. Up to 50% of patients with TLE suffer from anxiety and-or depression. Until relatively recently it had been widely assumed that this was a consequence of the chronic epileptic condition. However, recent evidence suggests that there is ....This project has the potential to provide novel insights about the causal connections between stress, psychiatric illness (specifically anxiety and depression) and temporal lobe epilepsy (TLE) - the most common form of medical refractory epilepsy in the community. Up to 50% of patients with TLE suffer from anxiety and-or depression. Until relatively recently it had been widely assumed that this was a consequence of the chronic epileptic condition. However, recent evidence suggests that there is a bi-directional relationship, with the psychiatric conditions and stress also acting to aggravate the seizures and even predispose to the development of the epilepsy itself. Apart from gaining insights into causes of TLE, anxiety and depression, this framework has potential public health relevance suggesting approaches to the eventual primary and secondary prevention of both MTLE and its associated psychiatric co-morbidities, a neglected area at present. The use of an animal model allows investigation of aetiological processes that extend over the lifetime, which is exceptionally difficult to achieve in humans. Retrospective studies, such as case-control studies, although an indispensable research methods, are subject to bias and imprecision when it comes to measuring remote past exposures to stress, abuse, and deprivation. If the results of these experiments are consistent with our hypotheses, a very strong case would exist for exploring this relationship in human studies. The data would also provide a strong rationale for more aggressive detection and treatment of these psychiatric co-morbidities in TLE patients, in order to potentially modify the progression of the disorder as well as improve the quality of life of sufferers. The results of intervention studies in animal models may suggest specific mode of treatment to achieve this.Read moreRead less
Why Does Early Life Stress Aggravate Limbic Epileptogenesis?
Funder
National Health and Medical Research Council
Funding Amount
$540,116.00
Summary
High rates of anxiety and depression occur in individuals with temporal lobe epilepsy (TLE), the most common form of focal epilepsy in adults. Rats that have experienced early life stress show increased anxiety, decreased seizure thresholds and accelerated epilepsy as adults. We have important leads to mechanisms. The proposed study will better understand the mechanisms connecting early life stress and psychiatric disease to adult TLE, and to test interventions that may counteract these effects.
Increased Vulnerability To Stress During Opiate Dependence: Molecular, Anatomical, And Behavioural Correlates
Funder
National Health and Medical Research Council
Funding Amount
$272,640.00
Summary
Heroin addiction is a major health and societal problem in Australia. It is consistently associated with an adverse impact upon individual users, their families, and communities. It is a chronically relapsing condition for which few, if any effective prevention and treatment strategies exist. Moreover, why an individual initiates and maintains heroin taking remains unclear. Stress and negative emotions have a strong impact on heroin use. Stress may drive some individuals to start using heroin, s ....Heroin addiction is a major health and societal problem in Australia. It is consistently associated with an adverse impact upon individual users, their families, and communities. It is a chronically relapsing condition for which few, if any effective prevention and treatment strategies exist. Moreover, why an individual initiates and maintains heroin taking remains unclear. Stress and negative emotions have a strong impact on heroin use. Stress may drive some individuals to start using heroin, stress increases the pleasurable effects of heroin and stress increases the aversive effects of heroin withdrawal. These effects will encourage addiction and discourage addicts from seeking treatment. Stress can also cause an otherwise drug-free individual to relapse to heroin addiction despite having been drug-free for some time. In this project we will study why stress has such a large impact on heroin addicts and heroin addiction. We will test the hypothesis that heroin use actually produces profound alterations in the neural network in the brain which controls responses to stress. This project uses a simple animal model of heroin addiction whereby rats are injected with morphine to study the regulation of several genes which are important in responding to stress. We will also study how this exposure and changes in gene expression alter neurobiological, cardiovascular, and behavioural responses to stress. This project will identify parts of the brain that are altered during heroin addiction, and will also identify why heroin addicts are more vulnerable to stress than the general population. Therefore, this project will help us to identify targets for therapeutic intervention (both psychological and pharmacological) and possibly disrupt the addictive cycle.Read moreRead less
Mechanism Of Signal Transduction And Receptor Activation In Ligand Gated Ion Channel Receptors
Funder
National Health and Medical Research Council
Funding Amount
$551,560.00
Summary
This project seeks to provide fundamental new information about the means by which neurotransmitter receptors, which mediate fast synaptic neurotransmission, operate. This knowledge is important since the Cys-loop family of ligand gated ion channel receptors are responsible for a wide range of neuronal signalling and the control of both excitatory and inhibitory receptors. The Cys-loop receptors are modulated by both therapeutic drugs (eg. benzodiazepines, barbiturates, antiemetics) and by recre ....This project seeks to provide fundamental new information about the means by which neurotransmitter receptors, which mediate fast synaptic neurotransmission, operate. This knowledge is important since the Cys-loop family of ligand gated ion channel receptors are responsible for a wide range of neuronal signalling and the control of both excitatory and inhibitory receptors. The Cys-loop receptors are modulated by both therapeutic drugs (eg. benzodiazepines, barbiturates, antiemetics) and by recreational drugs (eg. alcohol, nicotine). They are also targets for development of new therapeutic drugs, such as allosteric modulators of nAChR for memory enhancement, or modulating GlyR to relieve spasticity or chronic pain. The project will use a range of molecular advances made by this and other laboratories to clarify how neurotransmitters enable their receptors to activate and signal. This fundamental information is of major medical significance as defective synaptic transmission, caused by mutations in ligand gated ion channel receptors, gives rise to a number of neurological and psychiatric disease states. The ligand gated receptors are also major targets for therapeutic drugs and the information gained in this study may also provide insights into new ways in which drugs could be used to enhance or inhibit synaptic signalling.Read moreRead less
An Examination Of Motor Functioning In Autism And Asperger's Disorder: An Analysis Of Gait & Cortical Brain Activity.
Funder
National Health and Medical Research Council
Funding Amount
$120,220.00
Summary
Autism is a developmental disorder characterised by a triad of deficits: delayed and atypical language development, impaired development of social skills, and ritualistic and stereotypic behaviour. Although not part of the standard diagnosis, movement disorders and gait abnormalities have been clinically observed in autism similar to those seen in Parkinson's disease. In addition, individuals with Asperger's disorder may appear more clumsy, have a stiff or awkward way of walking, and exhibit poo ....Autism is a developmental disorder characterised by a triad of deficits: delayed and atypical language development, impaired development of social skills, and ritualistic and stereotypic behaviour. Although not part of the standard diagnosis, movement disorders and gait abnormalities have been clinically observed in autism similar to those seen in Parkinson's disease. In addition, individuals with Asperger's disorder may appear more clumsy, have a stiff or awkward way of walking, and exhibit poor coordination in posture and gesture. It has been suggested that there is disruption within the basal-ganglia-thalamocortical circuitry (the region connecting the frontal and sub-cortical structures), which may cause the motor dysfunction seen in autism and Asperger's disorder. Few studies have attempted to isolate particular stages of motor functioning which may account for the coordination and motor delay observed clinically in autism and Asperger's disorder. A recent study of ours found evidence to suggest that motor planning deficiencies may account for the 'clumsy' movement patterns frequently reported in the autism - Asperger's disorder literature. Therefore, the aim of this research is to provide a comprehensive neurobehavioural and neurophysiological analysis of motor functioning in young people with autism and Asperger's disorder to further examine the exact stages of motor processing which are deficient in these disorder groups. Recent retrospective studies have shown that even as infants children with autism exhibit clear features of motor disturbance, which, if detected and clearly defined, could advance early diagnosis. In addition to advancing the clinical definition of autism and Asperger's disorder, a careful examination of motor disturbance may also illuminate the neurobiological underpinnings of these disorders.Read moreRead less
Inhibition Of Fear Memories By Extinction: Neural Substrates.
Funder
National Health and Medical Research Council
Funding Amount
$234,250.00
Summary
Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relati ....Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relatively little is known about the mechanisms by which fear memories can be inhibited or suppressed. Understanding this latter process is a key to the development of effective treatments for anxiety disorders such as PTSD where the patient suffers from persistent, intrusive, unwanted trauma memories. A common experimental procedure for reducing learned fear is to repeatedly expose the subject to a fear-eliciting stimulus but without any aversive outcome. This procedure leads to a progressive loss, or extinction, of the fear reactions elicited by the stimulus. Historically, the extinction of fear was thought to be due to an erasure of the fear memory. However, recent evidence shows that extinction inhibits, rather than erases, the fear memory. Because the fear memories remain intact, some structure(s) in the brain must inhibit activity in the fear pathway. This project uses extinction of conditioned fear reactions in rat subjects to determine the structure(s) in the brain that inhibit fear memories and their behavioural and cardiovascular expression. It brings together the expertise of four well-established researchers and uses a combination of behavioural, physiological, immunohistochemical, tract tracing, and lesion approaches to achieve this aim. The proposed experiments will reveal the structure(s) in the brain that control the inhibition of fear, as well as the site(s) of this inhibition in the fear pathwayRead moreRead less