Maron E.,University of Tartu |
Maron E.,Imperial College London |
Hettema J.M.,Virginia Commonwealth University |
Shlik J.,University of Ottawa |
Shlik J.,Royal Ottawa Mental Health Center
Molecular Psychiatry | Year: 2010
The molecular genetic research on panic disorder (PD) has grown tremendously in the past decade. Although the data from twin and family studies suggest an involvement of genetic factors in the familial transmission of PD with the heritability estimate near 40%, the genetic substrate underlying panicogenesis is not yet understood. The linkage studies so far have suggested that chromosomal regions 13q, 14q, 22q, 4q31-q34, and probably 9q31 are associated with the transmission of PD phenotypes. To date, more than 350 candidate genes have been examined in association studies of PD, but most of these results remain inconsistent, negative, or not clearly replicated. Only Val158Met polymorphism of the catechol-O-methyltransferase gene has been implicated in susceptibility to PD by several studies in independent samples and confirmed in a recent meta-analysis. However, the specific role of this genetic variation in PD requires additional analysis considering its gender-and ethnicity-dependent effect and putative impact on cognitive functions. The recent advantages in bioinformatics and genotyping technologies, including genome-wide association and gene expression methods, provide the means for far more comprehensive discovery in PD. The progress in clinical and neurobiological concepts of PD may further guide genetic research through the current controversies to more definitive findings. © 2010 Macmillan Publishers Limited All rights reserved.
Dulude L.,University of Ottawa |
Labelle A.,Ottawa Health Research Institute |
Labelle A.,Royal Ottawa Mental Health Center |
Knott V.J.,Ottawa Health Research Institute |
Knott V.J.,Royal Ottawa Mental Health Center
Journal of Clinical Psychopharmacology | Year: 2010
Context: Patients with schizophrenia have a high rate of cigarette smoking and also exhibit profound deficits in sensory processing, which may in part be ameliorated by the acute actions of smoke-inhaled nicotine. The mismatch negativity (MMN), a preattentive event-related potential index of auditory sensory memory, is diminished in schizophrenia. The MMN is increased in healthy controls with acute nicotine. Objective: To utilize the MMN to compare auditory sensory memory in minimally tobacco-deprived (3 hours) patients and matched tobacco-deprived smoking controls and to assess the effects of acute nicotine on MMN-indexed sensory memory processing in the patients. DESIGN:: Event-related potentials were recorded in 2 auditory oddball paradigms, one involving tone frequency changes (frequency MMN) and one involving tone duration changes (duration MMN). Controls were assessed once under nontreatment conditions, and patients were assessed twice under randomized double-blind treatment conditions involving placebo and nicotine (8 mg) gum. SETTING:: Outpatient mental health center. PATIENTS:: Twelve smokers with schizophrenia and twelve control smokers. RESULTS:: Compared with the controls, the patients showed reduced frequency-MMN (P < 0.001) and duration-MMN (P < 0.04) amplitudes. In addition to prolonging peak latency in duration MMN (P < 0.01), nicotine, relative to placebo, increased the amplitude of the patients' duration MMN (P < 0.01), but not their frequency MMN, to a level comparable with that seen in the controls. Conclusions: These preliminary findings demonstrate for the first time that acute nicotine can normalize temporal aspects of sensory memory processing in patients with schizophrenia, an effect that may be mediated by activation of α7 nicotinic acetylcholine receptors, the function of which is diminished in schizophrenia. These ameliorating actions of nicotine may have implications for understanding the close relationship between tobacco smoking and schizophrenia and for developing nicotinic pharmacotherapies to alleviate sensory memory impairments in schizophrenia. © 2010 Lippincott Williams & Wilkins.
Horton J.,Health Integrated |
Millar A.,University of Ottawa |
Labelle A.,Royal Ottawa Mental Health Center |
Knott V.J.,Ottawa Health Research Institute
Schizophrenia Research | Year: 2011
Event-related potential (ERP) probing of abnormal sensory processes in schizophrenia with the mismatch negativity (MMN) has shown impairments in auditory change detection, but knowledge of the acoustic features leading to this deficit is incomplete. Changes in the duration and frequency properties of sound stimuli result in diminished MMNs in schizophrenia but it is unclear as to whether this reduced responsiveness is seen with more subtle changes in sound frequency. In a sample of 19 healthy controls and 21 patients with chronic schizophrenia treated with clozapine, MMN was assessed in response to tone frequency changes of 5%, 10% and 20%, and to tone duration changes. Patients exhibited reduced amplitudes and shorter latencies than controls to all frequency changes, and attenuated amplitudes to tone duration increments and decrements. Clozapine dose was related to MMN, with increasing dose being positively associated with frequency-MMN amplitudes (10% Δf, 20% Δf) and negatively associated with the amplitude and latency of duration-MMNs. These data support the well-established findings of auditory sensory abnormality in schizophrenia and underscore the sensitivity of MMN to relatively small auditory change detection deficits that may appear to characterize chronic schizophrenia. © 2010 Elsevier B.V.
Lee E.K.,University of Ottawa |
Lee E.K.,Royal Ottawa Mental Health Center |
Douglass A.B.,University of Ottawa |
Douglass A.B.,Ottawa Health Research Institute
Canadian Journal of Psychiatry | Year: 2010
Although the precise function of sleep is unknown, decades of research strongly implicate that sleep has a vital role in central nervous system (CNS) restoration, memory consolidation, and affect regulation. Slow-wave sleep (SWS) and rapid eye movement (REM) sleep have been of significant interest to psychiatrists; SWS because of its putative role in CNS energy recuperation and cognitive function, and REM sleep because of its suggested involvement in memory, mood regulation, and possible emotional adaptation. With the advent of the polysomnogram, researchers are now beginning to understand some of the consequences of disrupted sleep and sleep deprivation in psychiatric disorders. The same neurochemistry that controls the sleep-wake cycle has also been implicated in the pathophysiology of numerous psychiatric disorders. Thus it is no surprise that several psychiatric disorders have prominent sleep symptoms. This review will summarize normal sleep architecture, and then examine sleep abnormalities and comorbid sleep disorders seen in schizophrenia, as well as anxiety, cognitive, and substance abuse disorders.
Bardell A.,University of Ottawa |
Lau T.,University of Ottawa |
Fedoroff J.P.,University of Ottawa |
Fedoroff J.P.,Ottawa Health Research Institute |
Fedoroff J.P.,Royal Ottawa Mental Health Center
International Psychogeriatrics | Year: 2011
Inappropriate sexual behavior (ISB) is an important topic in geriatrics; etiologies remain unclear and evidence for the efficacy of treatment strategies is limited. The aims of this study were to provide a description of the phenomenology of ISB in the geriatric population, to identify potential contributing factors, and to review the efficacy of interventions aimed at reducing ISB. Methods: A retrospective chart review was conducted of ten patients admitted to an academic inpatient geriatric psychiatry ward because of their ISB (study group) and ten patients matched in age and gender (control group). A comprehensive chart review inventory was done to determine variables that may contribute to ISB. For the study group, effectiveness, adverse effects, and discontinuation due to adverse effects of interventions aimed at reducing ISB were reviewed. Results: A significant finding was the association of a history of right frontal lobe stroke with ISB (Fisher's Exact Probability Test p < 0.05). Also significant was performance on cognitive testing and the presence of dementia (Fisher's Exact Probability Test p < 0.05) in the study group. Citalopram was well tolerated but with minimal reduction of ISB. Atypical antipsychotics olanzapine and risperidone were effective in some cases but also had adverse effects. Medroxyprogesterone acetate was well tolerated and effective in all cases in which it was utilized (n = 5). Conclusions: This study suggests that ISB in the geriatric population is associated with a history of right frontal lobe stroke and with severity of dementia. Case examples of pharmacologic interventions are reviewed. © 2011 International Psychogeriatric Association.