INTRODUCTION

This group aims to characterise the cognitive deficits associated with symptoms present in psychiatric disorders. A better understanding of cognition can then be used to assist with designing new and more effective treatments or psychological interventions. A psychosocial interventions subgroup assists with direct translation of research into psychosocial treatments.

Symptoms of psychiatric disorders include unusual beliefs or delusions, hearing voices or hallucinations and impaired thinking or thought disorder. Individuals who experience psychosis have a range of cognitive difficulties that affect language, memory and high level functions. These cognitive deficits have, in some cases, been linked to underlying brain abnormalities.

In the last year, the clinical registry within the Cognitive Neuropsychiatry Unit has grown. As well as patients with schizophrenia and bipolar disorder the registry now includes individuals with Alzheimer’s disease. 145 people are currently registered on the patient registry and 108 on the control registry.

HIGHLIGHTS

The Belief Formation Project

Delusions are false beliefs, sometimes with bizarre content, that are held with strong conviction even in the presence of contrary evidence. Delusions occur in a range of severe psychiatric and neurological disorders, and are experienced by 90% of schizophrenia patients and 25% of bipolar affective disorder patients.

The most commonly experienced delusions in schizophrenia include the belief that people are conspiring against you or trying to harm you (delusions of persecution), and the belief that non-specific social information is particularly relevant to you, or being directed at you (delusions of reference). Other prevalent delusions in schizophrenia include those with grandiose and/or religious themes (e.g. the belief that you are Jesus Christ), or the belief that alien forces are controlling your thoughts and actions (delusions of control).

Research has suggested individuals with delusions have deficits in reasoning, emotion processing and defaults in their real world knowledge. To date, most of this research has been carried out on patients with schizophrenia. Susan Rossell’s team is currently extending this work to examine other mental disorders including bipolar affective disorder, body dysmorphic disorder, anorexia nervosa, Alzheimer’s disease and first-episode psychotic patients. By investigating a range of disorders which are associated with delusions, it is hoped that a more comprehensive cognitive explanation of delusions, independent of other associated symptoms, can be established.

Schizophrenia and bipolar disorder

Recruitment and testing for the Belief Formation Project was completed in patients with schizophrenia and bipolar disorder. Data analysis is now underway. Preliminary data was presented at the Australian Society for Psychiatric Research in December 2006. As predicted, our data established that abnormal reasoning is not an adequate explanation for delusion formation, and that disturbed emotion processing is prevalent in those with delusions.

To extend our understanding of emotion processing deficits in delusions and develop our results on perceptual organization deficits, Nicole Joshua has devised a series of further visual processing experiments for her PhD. She aims to examine the hierarchy of procedures used when processing visual information in patients with schizophrenia and healthy controls; using tasks ranging from processing simple line drawings to complex scenes that include faces. From this data we hope to gain a greater understanding of why people with schizophrenia have difficulties processing more complex visual stimuli (e.g. correctly identifying emotions in faces). Nicole has tested 23 schizophrenia patients, 20 bipolar disorder patients and 20 healthy control participants and will finalise testing over the next few months.

Body dysmorphic disorder

Body dysmorphic disorder (BDD) is a preoccupation with an imagined deficit or a slight physical anomaly in appearance which causes significant distress or impairment in social, occupational or other important areas of functioning.

Surprisingly, there have been few studies to investigate cognitive functioning in BDD. Judy Dunai (for her Masters in Clinical Psychology) and Izelle Labuschagne, in collaboration with David Castle and Mike Kyrios, have embarked upon a detailed investigation of the cognitive processes involved in belief formation in individuals with BDD. Data collection is now complete and shows that patients with BDD have significant difficulty accurately detecting facial emotions.

In January 2007, Wei Lin Toh joined us to extend this research. She is examining whether deficits in facial affect processing are the result of selective attentional biases or a problem with eye scanning abilities. An ethics submission for this project has just been completed.

Anorexia nervosa

Anorexia Nervosa (AN) is a chronic eating disorder characterised by excessive fear of becoming overweight, body image disturbance, significant weight loss and the refusal to gain weight or maintain a minimal normal weight for age and height. The beliefs that people with AN hold about their bodies are usually characterised as overvalued ideas (an unreasonable and sustained belief that is held without delusional intensity).

In a recent review of the nature of delusions, delusional intensity is conceptualised as being multi-dimensional; varying on dimensions such as conviction, preoccupation, distress and action. Defining beliefs in AN as overvalued ideas rather than delusions suggests that such beliefs are not held with the same degree of conviction, preoccupation and fixity as delusions in psychotic disorders. However, the intense fear of and refusal for weight gain that characterise AN, despite malnutrition and impaired health status, may imply otherwise.

No study has examined (a) whether the beliefs in AN share the same features as psychotic delusions, or (b) whether similar cognitive deficits are shared by both disorders. Rachel Mountjoy will be examining these two questions for her Doctorate of Clinical Psychology. Ethics approval has now been gained for this project and recruiting commenced in June 2007.

Alzheimer’s disease

Alzheimer’s disease (AD) is a progressive brain disorder that gradually destroys a person’s memory and ability to learn, reason, make judgements, communicate and carry out daily activities. We are familiar with memory loss as a symptom of the disease; however the illness is much more complex. As AD progresses, individuals may also experience changes in personality and behaviour, such as anxiety, suspiciousness or agitation; as well as delusions.

Delusions have recently been reported to be a common symptom in AD and are associated with a number of adverse outcomes; for example, greater aggression, caregiver stress and earlier institutionalisation or dependence for daily living activities. Yet, there has been limited research in this field. There is a poor understanding of the types of delusions experienced in AD, their frequency, and the demographic and cognitive risk factors. Furthermore, there is no consensus as to what role stage of organic disease plays on the presence of delusions, which in turn means that there has been no study to address the neurobiological changes involved in the generation of delusional beliefs in AD. Funded by a Claudia Wright Scholarship, David O’Connor will address these gaps in our understanding for his PhD.

First episode psychosis

As part of her Masters in Clinical Psychology, Clare Cameron will be investigating whether the deficits in knowledge or semantic processing reported in Dr Rossell’s work are also present at first presentation of a psychotic episode. This will help clarify whether semantic deficits seen in schizophrenia patients are due to a developmental problem, a slow disintegration where deficits first show at the first signs of psychosis, or medication chronicity.

The results of this study will have implications for clinical treatment: if semantic processing abnormalities are not present in first-onset psychosis patients, steps can be taken to prevent the deterioration of semantic processing. Recruiting for this project commenced in early 2007. Clare is supervised by Susan Rossell and Lisa Phillips.

Gender, oestrogen and sensory information processing

Dr Andrea Gogos is collaborating with Susan Rossell on a project examining the interaction of gender, oestrogen and brain mechanisms that alter sensory information processing in men and women with schizophrenia and bipolar disorder. In this study, participant performance on various cognitive measures, such as memory, attention and information processing, is compared.

A second, follow-up study is being conducted in healthy women to specifically investigate the effects of endogenous oestrogen levels on cognitive function and sensory information processing. In this study, women are tested at various stages of the menstrual cycle, where oestrogen levels dramatically rise and fall. Andrea is also examining the interaction between exogenous oestrogen and serotonin on sensory information processing in healthy women. These studies are ongoing and are supported by funding from the Joan and Peter Clemenger Trust.

Understanding Auditory Hallucinations

Hallucinations in psychosis are predominately auditory in nature. Previous research has shown that patients with auditory hallucinations (AH) have deficits in central auditory processing. The Cognitive Neuropsychiatry group has established that this may be the result of reduced interhemispheric connectivity; a theory that has resulted in several publications.

In December 2006 we secured funding from the Rebecca L Cooper Medical Research Foundation to continue work in this area and welcomed a new PhD student, Chris Groot. Chris will be examining whether we can further classify central auditory processing deficits to more basic auditory perceptual abilities, for example whether individuals who hear voices have problems with pitch or loudness perception.

Primary Auditory Cortex

The Impaired Thought Project

Disorganised thinking and speech, or ‘formal thought disorder’, has been argued by some to be one of the most important symptoms of schizophrenia and, along with hallucinations and delusions, is certainly a cardinal feature.

To date, there has been no satisfactory cognitive explanation for thought disorder. Approaches have emphasised the relationship between semantic processing abnormalities and thought disorder. However, Dr Rossell speculates that this provides an over-simplistic explanation, and it is likely that a single cognitive deficit does not account for thought disorder but that multiple deficits affecting specific levels of linguistic processing (e.g. syntax, semantics and ‘fluency or executive control’) are involved. Ongoing funding from a NARSAD Young Investigator Award is assisting Susan to examine this hypothesis.

TORCH (Treatment of Resistant Command Hallucinations) Project

Command hallucinations (CHs) are a form of auditory hallucination (AH) sometimes experienced by individuals with schizophrenia and related psychoses that instruct the person to perform an action(s). Command hallucinations are associated with significant levels of disability and distress.

Over the past year, we have completed a trial of a psychological treatment for CHs that works alongside antipsychotic medication to help people cope with these symptoms. TORCH is a form of Cognitive Behaviour Therapy that has been adapted for command hallucinations and incorporates cutting edge developments in psychological therapies. It comprises 15 sessions with a therapist. Our trial compared TORCH with a control condition, ‘Befriending’, in which participants received an equivalent amount of therapist contact, without the active therapeutic components of TORCH. We are currently analysing results for publication.

The Voices Clinic

We have established a specialist treatment service for auditory hallucinations. With support from The William Buckland Foundation, we are piloting the Voices Clinic: a specialist service which receives referrals from clinical services throughout Victoria.

Unique in Australia, the clinic is run by Dr Neil Thomas, an expert in the psychological treatment of schizophrenia. There is a clear need for this type of service, given a shortfall in the availability of psychological treatments for patients with severe mental illness. The clinic is a tertiary service which provides evidence-based psychological treatment to patients, alongside their regular treatment from public mental health services or private psychiatrists. Treatment comprises regular one-to-one therapy sessions for up to six months, aiming to reduce levels of distress and disability associated with auditory hallucinations.

In addition to providing direct treatment, the Voices Clinic provides training to mental health practitioners across Victoria in the form of training workshops and supervision. Through such professional development activities we hope to improve access to this important treatment. The Voices Clinic has formed partnerships with a number of public mental health services to whom it provides regular specialist supervision in the psychological treatment of psychotic symptoms. We are currently investigating the ongoing running of the clinic following the pilot period in conjunction with public mental health services.