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Amanda Baker

Publications and source records attributed to Amanda Baker.

15 recordsLinked to original sources
PubMed2006

Where there's smoke, there's fire: high prevalence of smoking among some sub-populations and recommendations for intervention.

In Australia, the prevalence of smoking is higher among certain sub-populations compared to the general population. These sub-populations include Aboriginal and Torres Strait Islander people, people from culturally and linguistically diverse backgrounds, as well as people with mental and substance use disorders and prisoners. The aims of this paper are to: describe the high prevalence of smoking among these particular sub-populations and harms associated with smoking; explore possible reasons for such high prevalence of smoking; review the evidence regarding the efficacy of existing smoking cessation interventions; and make recommendations for smoking interventions and further research among these groups. In addition to low socio-economic status, limited education and other factors, there are social, systems and psychobiological features associated with the high prevalence of smoking in these sub-groups. General population-based approaches to reducing smoking prevalence have been pursued for decades with great success and should be continued with further developments that aim specifically to affect Aboriginal and Torres Strait Islander people and some cultural groups. However, increasing attention, more specific targeting and flexible goals and interventions are also required for these and other distinct sub-populations with high smoking prevalence. Recommendations include: more funding and increased resources to examine the most appropriate education and treatment strategies to promote smoking cessation among people from Aboriginal and Torres Strait Islander and some culturally and linguistically diverse backgrounds; larger and better-designed studies evaluating smoking cessation/reduction interventions among distinct sub-groups; and system-wide interventions requiring strong leadership among clients and staff within mental health, drug and alcohol and prison settings.

Alcoholism↗
PubMed2006

Long-term follow-up of people with co-existing psychiatric and substance use disorders: patterns of use and outcomes.

The aims of this study were to document long-term patterns of substance use among people with co-existing psychiatric and substance use disorders and to explore differences in psychosocial outcomes for groups with different substance use outcome profiles (persistent hazardous, intermittent hazardous and non-hazardous users). An opportunistic long-term (4 - 6 years) follow-up interview was conducted with participants from a previous study who were recruited during their inpatient admission at a public psychiatric hospital in Newcastle, New South Wales, Australia. Follow-up data were obtained from 47 people from the original study and combined with their existing baseline, 6-month and 12-month data. The follow-up interview included demographic variables and measures of substance use, psychiatric symptomatology and a range of psychosocial variables. Alcohol, cannabis and amphetamines were the most commonly misused substances. Persistent hazardous users experienced poorer outcomes in the domains of social functioning and psychiatric symptomatology, including depression, than intermittently hazardous or non-hazardous users. An unusually high mortality rate of 10% among the males in the original sample (12/120) was an unexpected finding, particularly as this was likely to be an underestimate. Given the differences in outcomes between groups with varied gradations of substance use, a harm minimisation approach for research and practice among people with co-existing psychiatric and substance use disorders is endorsed.

Adult↗
PubMed2006

A randomized controlled trial of a smoking cessation intervention among people with a psychotic disorder.

OBJECTIVE: Despite extremely high rates of smoking among individuals with psychotic disorders and the associated financial and health costs, few studies have investigated the efficacy of smoking cessation interventions among this group. The purpose of this study was to compare an integrated psychological and nicotine replacement therapy intervention for people with a psychotic disorder with routine care alone. METHOD: The authors recruited 298 regular smokers with a psychotic disorder residing in the community and randomly assigned them to a routine care comparison condition (N=151) or an eight-session, individually administered smoking cessation intervention (N=147), which consisted of nicotine replacement therapy, motivational interviewing, and cognitive behavior therapy. Outcome variables included continuous and point-prevalence abstinence rates, smoking reduction status, and changes in symptoms and functioning. RESULTS: While there were no overall differences between the treatment group and comparison group in abstinence rates, a significantly higher proportion of smokers who completed all treatment sessions stopped smoking at each of the follow-up occasions (point-prevalence rates: 3 months, 30.0% versus 6.0%; 6 months, 18.6% versus 4.0%; and 12 months, 18.6% versus 6.6%). Smokers who completed all treatment sessions were also more likely to have achieved continuous abstinence at 3 months (21.4% versus 4.0%). There was a strong dose-response relationship between treatment session attendance and smoking reduction status, with one-half of those who completed the intervention program achieving a 50% or greater reduction in daily cigarette consumption across the follow-ups, relative to less than one-fifth of the comparison subjects. There was no evidence of any associated deterioration in symptoms or functioning. CONCLUSIONS: These findings demonstrate the utility of a nicotine replacement therapy plus motivational interviewing/cognitive behavior therapy smoking cessation intervention among individuals with a psychotic disorder. Further development of more efficacious interventions is required for those who do not respond to existing interventions.

Adult↗
PubMed2006

Cognitive-behavioural therapy for substance use disorders in people with psychotic disorders: Randomised controlled trial.

BACKGROUND: Few randomised controlled trials have been aimed specifically at substance use reduction among people with psychotic disorders. AIMS: To investigate whether a 10-session intervention consisting of motivational interviewing and cognitive-behavioural therapy (CBT) was more efficacious than routine treatment in reducing substance use and improving symptomatology and general functioning. METHOD: A community sample of people with a psychotic disorder and who reported hazardous alcohol, cannabis and/or amphetamine use during the preceding month was recruited. Participants were randomly allocated to motivational interviewing/CBT (n = 65) or treatment as usual (n = 65), and were assessed on multiple outcomes at baseline, 15 weeks, 6 months and 12 months. RESULTS: There was a short-term improvement in depression and a similar trend with regard to cannabis use among participants who received the motivational interviewing/CBT intervention, together with effects on general functioning at 12 months. There was no differential benefit of the intervention on substance use at 12 months, except for a potentially clinically important effect on amphetamine use. CONCLUSIONS: The motivational interviewing/CBT intervention was associated with modest improvements.

Adolescent↗
PubMed2005

Comparisons between psychosis samples with different patterns of substance use recruited for clinical and epidemiological studies.

Despite high rates of comorbid substance use disorders and smoking among people with psychotic disorders, previous studies have not examined differences in socio-demographic, clinical or disability characteristics between psychosis sub-groups with different patterns of substance use. This study compared the characteristics of five groups of people with psychosis and varying patterns of substance use (n=1152), including groups entering treatment studies for substance use or smoking, epidemiological samples of substance users and smokers, and people without such problems. Data were drawn from several recent Australian studies using comparable structured interviews and scales. There were moderate group differences in illness and symptom profiles, with substance users tending to have higher depression and reality distortion scores. Unexpectedly, personal disability was considerably lower among those seeking treatment for their substance use compared with the epidemiological groups, raising concerns about the appropriateness of traditional recruitment approaches in treatment studies and highlighting the need for more assertive treatment engagement and referral strategies in routine clinical settings. As a consequence of uncertainty about links between substance use and everyday functioning, it is suggested that health messages to young people may need to strike a better balance between the potential harms and benefits associated with substance use in pursuing broader harm minimization goals.

Adolescent↗
PubMed2005

Brief cognitive behavioural interventions for regular amphetamine users: a step in the right direction.

AIMS: The present study sought to replicate and extend a small pilot study conducted by Baker, Boggs & Lewin (2001) which demonstrated that brief interventions consisting of motivational interviewing and cognitive-behaviour therapy (CBT) were feasible and associated with better outcomes compared with a control condition. DESIGN: Randomized controlled trial (RCT). SETTING: Greater Brisbane Region of Queensland and Newcastle, NSW, Australia. PARTICIPANTS: The study was conducted among 214 regular amphetamine users. MEASUREMENTS: Demographic characteristics, past and present alcohol and other drug use and mental health, treatment, amphetamine-related harms and severity of dependence. FINDINGS: The main finding of this study was that there was a significant increase in the likelihood of abstinence from amphetamines among those receiving two or more treatment sessions. In addition, the number of treatment sessions attended had a significant short-term beneficial effect on level of depression. There were no intervention effects on any other variables (HIV risk-taking, crime, social functioning and health). Overall, there was a marked reduction in amphetamine use among this sample over time and, apart from abstinence rates and short-term effects on depression level, this was not differential by treatment group. Reduction in amphetamine use was accompanied by significant improvements in stage of change, benzodiazepine use, tobacco smoking, polydrug use, injecting risk-taking behaviour, criminal activity level, and psychiatric distress and depression level. CONCLUSIONS: A stepped-care approach is recommended. The first step in providing an effective intervention among many regular amphetamine users, particularly those attending non-treatment settings, may include provision of: a structured assessment of amphetamine use and related problems; self-help material; and regular monitoring of amphetamine use and related harms. Regular amphetamine users who present to treatment settings could be offered two sessions of CBT, while people with moderate to severe levels of depression may best be offered four sessions of CBT for amphetamine use from the outset, with further treatment for amphetamine use and/or depression depending on response. Pharmacotherapy and/or longer-term psychotherapy may be suitable for non-responders. An RCT of a stepped-care approach among regular amphetamine users is suggested.

Adult↗
PubMed2005

The phosphatidylinositol-3-kinase inhibitor PX-866 overcomes resistance to the epidermal growth factor receptor inhibitor gefitinib in A-549 human non-small cell lung cancer xenografts.

Epidermal growth factor receptor (EGFR) inhibitors such as gefitinib show antitumor activity in a subset of non-small cell lung cancer (NSCLC) patients having mutated EGFR. Recent work shows that phosphatidylinositol-3-kinase (PI3-K) is coupled to the EGFR only in NSCLC cell lines expressing ErbB-3 and that EGFR inhibitors do not inhibit PI3-K signaling in these cells. The central role PI3-K plays in cell survival suggests that a PI3-K inhibitor offers a strategy to increase the antitumor activity of EGFR inhibitors in resistant NSCL tumors that do not express ErbB-3. We show that PX-866, a PI3-K inhibitor with selectivity for p110alpha, potentiates the antitumor activity of gefitinib against even large A-549 NSCL xenografts giving complete tumor growth control in the early stages of treatment. A-549 xenograft phospho-Akt was inhibited by PX-866 but not by gefitinib. A major toxicity of PX-866 administration was hyperglycemia with decreased glucose tolerance, which was reversed upon cessation of treatment. The decreased glucose tolerance caused by PX-866 was insensitive to the AMP-activated protein kinase inhibitor metformin but reversed by insulin and by the peroxisome proliferator-activated receptor-gamma activator pioglitazone. Prolonged PX-866 administration also caused increased neutrophil counts. Thus, PX-866, by inhibiting PI3-K signaling, may have clinical use in increasing the response to EGFR inhibitors such as gefitinib in patients with NSCLC and possibly in other cancers who do not respond to EGFR inhibition.

Animals↗
PubMed2005

Dynamic contrast-enhanced and diffusion MRI show rapid and dramatic changes in tumor microenvironment in response to inhibition of HIF-1alpha using PX-478.

PX-478 is a new agent known to inhibit the hypoxia-responsive transcription factor, HIF-1alpha, in experimental tumors. The current study was undertaken in preparation for clinical trials to determine which noninvasive imaging endpoint(s) is sensitive to this drug's actions. Dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor hemodynamics and cellularity, respectively. Mice bearing human xenografts were treated either with PX-478 or vehicle, and imaged over time. DW imaging was performed at three b values to generate apparent diffusion coefficient of water (ADCw) maps. For DCE-MRI, a macromolecular contrast reagent, BSA-Gd-DTPA, was used to determine vascular permeability and vascular volume fractions. PX-478 induced a dramatic reduction in tumor blood vessel permeability within 2 hours after treatment, which returned to baseline by 48 hours. The anti-VEGF antibody, Avastin, reduced both the permeability and vascular volume. PX-478 had no effect on the perfusion behavior of a drug-resistant tumor system, A-549. Tumor cellularity, estimated from ADCw, was significantly decreased 24 and 36 hours after treatment. This is the earliest significant response of ADC to therapy yet reported. Based on these preclinical findings, both of these imaging endpoints will be included in the clinical trial of PX-478.

Animals↗
PubMed2004

Drug use patterns and mental health of regular amphetamine users during a reported 'heroin drought'.

AIMS: The present study extends the findings of a pilot study conducted among regular amphetamine users in Newcastle, NSW, in 1998. It compares key features between current participants in a state capital city (Brisbane) and a regional city (Newcastle) and between the 1998 and current Newcastle sample. DESIGN: Cross-sectional survey. Setting Brisbane and Newcastle, Australia. PARTICIPANTS: The survey was conducted among 214 regular amphetamine users within the context of a randomized controlled trial of brief interventions for amphetamine use. MEASUREMENTS: Demographic characteristics, past and present alcohol and other drug use and mental health, treatment, amphetamine-related harms and severity of dependence. FINDINGS: The main findings were as follows: (i). the rate of mental health problems was high among regular amphetamine users and these problems commonly emerged after commencement of regular amphetamine use; (ii). there were regional differences in drug use with greater accessibility to a wider range of drugs in a state capital city and greater levels of injecting risk-taking behaviour outside the capital city environment; and (iii). there was a significant increase in level of amphetamine use and percentage of alcohol users, a trend for a higher level of amphetamine dependence and a significant reduction in the percentage of people using heroin and benzodiazepines among the 2002 Newcastle cohort compared to the 1998 cohort. CONCLUSIONS: Further longitudinal research is needed to elucidate transitions from one drug type to another and from recreational to injecting and regular use and the relationship between drug use and mental health in prospective studies among users. IMPLICATIONS: Intervention research should evaluate the effectiveness of interventions aimed at: preventing transition to injecting and regular use of amphetamines; toward reducing levels of depression among amphetamine users and interventions among people with severe psychopathology and personality disorders; and toward reducing the prevalence of tobacco dependence among amphetamine users.

Adolescent↗
PubMed2003

A review of psychosocial interventions for amphetamine use.

There are clear signs that amphetamine use is increasing in Australia and internationally, yet there are few services that offer amphetamine-specific interventions. This review examines the evidence for the use of psychosocial interventions for amphetamine users. The literature is very limited in the number of well-conducted, controlled studies, but the evidence available suggests that cognitive-behavioural therapy appears to be current best practice. Motivational interviewing has been recommended as a strategy to assist those ambivalent for treatment. There is also some evidence that contingency management is effective while clients are in treatment. The effectiveness of other types of intervention is not well supported. The literature is particularly hindered by a paucity of well-conducted studies among primary amphetamine users. Recommendations about appropriate interventions for use in clinical settings are offered and directions for future research are considered.

Amphetamine-Related Disorders↗
PubMed2002

Correlates of nontransmission in US women at high risk of human immunodeficiency virus type 1 infection through sexual exposure.

Seventeen women who were persistently uninfected by human immunodeficiency virus type 1 (HIV-1), despite repeated sexual exposure, and 12 of their HIV-positive male partners were studied for antiviral correlates of non-transmission. Thirteen women had > or = 1 immune response in the form of CD8 cell noncytotoxic HIV-1 suppressive activity, proliferative CD4 cell response to HIV antigens, CD8 cell production of macrophage inflammatory protein-1 beta, or ELISPOT assay for HIV-1-specific interferon-gamma secretion. The male HIV-positive partners without AIDS had extremely high CD8 cell counts. All 8 male partners evaluated showed CD8 cell-related cytotoxic HIV suppressive activity. Reduced CD4 cell susceptibility to infection, neutralizing antibody, single-cell cytokine production, and local antibody in the women played no apparent protective role. These observations suggest that the primary protective factor is CD8 cell activity in both the HIV-positive donor and the HIV-negative partner. These findings have substantial implications for vaccine development.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Motivational interviewing among psychiatric in-patients with substance use disorders.

OBJECTIVE: There were three aims of the present study: 1) to document patterns of substance misuse among psychiatric in-patients with comorbid alcohol and other drug (AOD) use; 2) to examine associations among psychiatric and substance use diagnoses and readiness to change; and 3) to evaluate the effectiveness of an opportunistic motivational interview on engagement in a Specialist Substance Misuse Service (SSMS). METHOD: One hundred and sixty subjects were randomly assigned to receive either a motivational interview or no intervention. RESULTS: Overall, 66.3% of subjects met intervention threshold for cannabis, 60.6% for alcohol and 22.5% for amphetamines. There was a bimodal distribution of stage of change for cannabis use which was associated with age, with precontemplation being associated with older age and less frequent use. Attendance at the SSMS was low and unrelated to intervention status. CONCLUSION: A different approach to treatment is recommended, including early intervention among cannabis users.

Adolescent↗
PubMed2002

Evaluation of a motivational interview for substance use within psychiatric in-patient services.

AIMS: To assess the effectiveness of a motivational interview among hospitalized psychiatric patients with comorbid substance use disorder in reducing alcohol and other drug (AOD) use. DESIGN: Subjects were assigned randomly to receive an individual motivational interview (n=79) or a self-help booklet (control condition; n=81). SETTING: Subjects were volunteers recruited from a major public psychiatric hospital. PARTICIPANTS: Subjects met abuse or dependence criteria on the structured clinical interview for diagnosis (SCID) for alcohol, cannabis or amphetamine or they reported hazardous use during the last month of one or more of these drug types on the opiate treatment index (OTI). INTERVENTION: Either one 30-45-minute motivational interview or brief advice. MEASUREMENTS: The SCID and OTI were the main measures. FINDINGS: There was a modest short-term effect of the motivational interview on an aggregate index of alcohol and other drug use (polydrug use on the OTI). Cannabis use remained high among the sample over the 12-month follow-up period. CONCLUSION: Although motivational interviewing appears feasible among in-patients in psychiatric hospital with comorbid substance use disorders, more extensive interventions are recommended, continuing on an out-patient basis, particularly for cannabis use.

Adult↗