Psychiatry - Research Publications
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ItemCingulate biochemistry in heroin users on substitution pharmacotherapy(SAGE PUBLICATIONS LTD, 2013-03-01)OBJECTIVE: High doses of opiate substitution pharmacotherapy are associated with greater treatment retention and lower illicit drug consumption, although the neurobiological bases of these benefits are poorly understood. Dysfunction of the anterior cingulate cortex (ACC) is associated with greater addiction severity and mood dysregulation in opiate users, such that the beneficial effects of substitution pharmacotherapy may relate to normalisation of ACC function. This study aimed to investigate the differential impact of methadone compared with buprenorphine on dorsal ACC biochemistry. A secondary aim was to explore the differential effects of methadone and buprenorphine on dorsal ACC biochemistry in relation to depressive symptoms. METHODS: Twenty-four heroin-dependent individuals stabilised on methadone (n=10) or buprenorphine (n=14) and 24 healthy controls were scanned using proton Magnetic Resonance Spectroscopy and compared for metabolite concentrations of N-acetylaspartate, glutamate/glutamine, and myo-inositol. RESULTS: (1) Methadone was associated with normalisation of dorsal ACC biochemistry (increased N-acetylaspartate and glutamate/glutamine levels, and decreased myo-inositol levels) in a dose-dependent manner; (2) buprenorphine-treated individuals had higher myo-inositol and glutamate/glutamine levels than methadone-treated patients in the right dorsal ACC; and (3) myo-inositol levels were positively correlated with depressive symptoms in participants stabilised on buprenorphine. CONCLUSIONS: These findings point to a beneficial role of high-dose methadone on dorsal ACC biochemistry, and suggest a link between elevated myo-inositol levels and depressive symptoms in the context of buprenorphine treatment.
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ItemChronic adrenocorticotrophic hormone treatment alters tricyclic antidepressant efficacy and prefrontal monoamine tissue levels(ELSEVIER, 2013-04-01)Several animal models are currently utilised in the investigation of major depressive disorder; however, each is validated by its response to antidepressant pharmacotherapy. Few animal models consider the notion of antidepressant treatment resistance. Chronic daily administration of adrenocorticotropic hormone (ACTH) or corticosterone can alter behavioural responses to antidepressants, effectively blocking antidepressant efficacy. Herein, we demonstrate that ACTH-(1-24) (100μg/day; 14 days) blocks the immobility-reducing 'antidepressant' effects of a single dose of imipramine (10mg/kg) in the forced swim test. This finding was accompanied by altered monoamine tissue levels in the prefrontal cortex (PFC) 1h after exposure to the acute stress of the forced swim test. PFC tissue from ACTH pre-treated animals contained significantly higher serotonin, noradrenaline and adrenaline concentrations relative to saline pre-treated controls. Conversely, dopamine levels were significantly decreased. Altered plasma corticosterone responses to ACTH injections were observed over the treatment course. Measures were taken on treatment days 1, 4, 8, 11, 14 and 15. ACTH administration initially enhanced plasma corticosterone levels, however, these normalised to levels consistent with control animals by day 14. No differences in corticosterone levels were observed across the treatment time course in saline-treated animals. Taken together these results indicate that pre-treatment with ACTH (100μg/day; 14 days) blocks the antidepressant effects of imipramine (10mg/kg), significantly alters key PFC monoamine responses to stress and downregulates glucocorticoid responses. These results suggest that chronic ACTH treatment is a promising paradigm for elucidation of mechanisms mediating antidepressant treatment resistance.
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ItemPharmacological management of unipolar depression(WILEY, 2013-05-01)
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ItemSystematic Review of the Effectiveness of Pharmacologic Interventions to Improve Quality of Life and Well-being in People With Dementia(ELSEVIER SCIENCE INC, 2013-02-01)OBJECTIVE: To review systematically, for the first time, the effectiveness of all pharmacologic interventions to improve quality of life and well-being in people with dementia. DESIGN: Systematic review and meta-analysis. METHODS: We systematically reviewed the 15 randomized controlled trials and one review that fitted predetermined criteria. We included studies that reported the outcomes quality of life, well-being, happiness, or pleasure. MEASUREMENTS: We rated the validity of studies using a checklist. We calculated mean differences between intervention and control groups at follow-up. RESULTS: None of the evaluated trials reported a significant benefit to quality of life or well-being for people with dementia when comparing those taking a drug or its comparator at follow-up (pooled weighted mean difference: 0.18 [95% confidence interval: -0.82 to 0.46]). CONCLUSION: We found no consistent evidence that any drug improves quality of life in people with dementia. We recommend that all dementia trials should include quality of life as an outcome, as this is important to patients, and cannot be presumed from improvements in cognition or other symptomatic outcomes, especially if the latter are small.