Rajiv Tandon
University of Florida
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Featured researches published by Rajiv Tandon.
Schizophrenia Research | 2009
Rajiv Tandon; Henry A. Nasrallah; Matcheri S. Keshavan
Although dementia praecox or schizophrenia has been considered a unique disease entity for the past century, its definitions and boundaries have continued to vary over this period. At any given time, the changing concept of schizophrenia has been influenced by available diagnostic tools and treatments, related conditions from which it most needs to be distinguished, extant knowledge and scientific paradigms. There is significant heterogeneity in the etiopathology, symptomatology, and course of schizophrenia. It is characterized by an admixture of positive, negative, cognitive, mood, and motor symptoms whose severity varies across patients and through the course of the illness. Positive symptoms usually first begin in adolescence or early adulthood, but are often preceded by varying degrees of negative and cognitive symptomatology. Schizophrenia tends to be a chronic and relapsing disorder with generally incomplete remissions, variable degrees of functional impairment and social disability, frequent comorbid substance abuse, and decreased longevity. Although schizophrenia may not represent a single disease with a unitary etiology or pathogenetic process, alternative approaches have thus far been unsuccessful in better defining this syndrome or its component entities. The symptomatologic, course, and etio-pathological heterogeneity can usefully be addressed by a dimensional approach to psychopathology, a clinical staging approach to illness course, and by elucidating endophenotypes and markers of illness progression, respectively. This will allow an approach to the deconstruction of schizophrenia into its multiple component parts and strategies to reconfigure these components in a more meaningful manner. Possible implications for DSM-V and ICD-11 definitions of schizophrenia are discussed.
Schizophrenia Research | 2010
Rajiv Tandon; Henry A. Nasrallah; Matcheri S. Keshavan
The introduction of second-generation antipsychotics and cognitive therapies for schizophrenia over the past two decades generated considerable optimism about possibilities for recovery. To what extent have these developments resulted in better outcomes for affected individuals? What is the current state of our science and how might we address the many unmet needs in the prevention and treatment of schizophrenia? We trace the evolution of various treatments for schizophrenia and summarize current knowledge about available pharmacological and psychosocial treatments. We consider the widely prevalent efficacy-effectiveness gap in the application of available treatments and note the significant variability in individual treatment response and outcome. We outline an individualized treatment approach which emphasizes careful monitoring and collaborative decision-making in the context of ongoing benefit-risk assessment. We note that the evolution of both pharmacological and psychosocial treatments thus far has been based principally on serendipity and intuition. In view of our improved understanding of the etiology and pathophysiology of schizophrenia, there is an opportunity to develop prevention strategies and treatments based on this enhanced knowledge. In this context, we discuss potential psychopathological treatment targets and enumerate current pharmacological and psychosocial development efforts directed at them. Considering the stages of schizophrenic illness, we review approaches to prevent progression from the pre-symptomatic high-risk to the prodrome to the initial psychotic phase to chronicity. In view of the heterogeneity of risk factors, we summarize approaches towards targeted prevention. We evaluate the potential contribution of pharmacogenomics and other biological markers in optimizing individual treatment and outcome in the future.
Schizophrenia Research | 2008
Rajiv Tandon; R.H. Belmaker; Wagner F. Gattaz; Juan José López-Ibor; Ahmed Okasha; Bruce Singh; Dan J. Stein; Jean-Pierre Olié; W. Wolfang Fleischhacker; Hans-Juergen Moeller
Data from two major government-funded studies of comparative antipsychotic effectiveness in schizophrenia contradict the widely prevalent belief that the newer second-generation medications are vastly superior to the older first-generation drugs. This has caused uncertainty among patients, clinicians and policy-makers about the relative utility of first- and second- generation antipsychotic agents in its treatment. To reduce confusion and provide a contextual understanding of the new data, the World Psychiatry Association Section on Pharmacopsychiatry comprehensively reviewed the literature on the comparative effectiveness of different antipsychotic treatments for schizophrenia and developed this update. Utilizing data from the approximately 1,600 randomized controlled trials of antipsychotic treatment in schizophrenia, we applied the two indirect and one direct method to comparing the effectiveness of 62 currently-available antipsychotic agents. The subclasses of 51 first-generation and 11 second-generation antipsychotics were both found to be very heterogeneous, with substantial differences in side-effect profiles among members. Second-generation antipsychotic agents were found to be inconsistently more effective than first-generation agents in alleviating negative, cognitive, and depressive symptoms and had a lower liability to cause tardive dyskinesia; these modest benefits were principally driven by the ability of second-generation antipsychotics to provide equivalent improvement in positive symptoms along with a lower risk of causing extrapyramidal side-effects. Clozapine was found to be more efficacious than other agents in treatment-refractory schizophrenia. There were no consistent differences in efficacy among other second-generation antipsychotic agents; if such differences exist, they are likely small in magnitude. Dosing was found to be a key variable in optimizing effectiveness of both first- and second- generation antipsychotic agents. There was enormous individual variability in antipsychotic response and vulnerability to various adverse effects. In contrast to their relatively similar efficacy in treating positive symptoms, there were substantial differences among both first- and second- generation antipsychotic agents with regard to their propensity to cause extrapyramidal, metabolic and other adverse effects; second-generation agents have a lower liability to cause acute extrapyramidal symptoms and tardive dyskinesia along with a tendency to cause greater metabolic side-effects than first-generation agents. Based on these data about the comparative effectiveness of different antipsychotic treatment options, we summarize elements of current best antipsychotic practice for the treatment of schizophrenia and discuss the role of government and the pharmaceutical industry in obtaining and disseminating information which can facilitate best practice.
Schizophrenia Research | 1991
Rajiv Tandon; James E. Shipley; John F. Greden; Nancy A. Mann; William H. Eisner; Jo Ann Goodson
Based on the implication of increased muscarinic ACh activity in the production of negative symptoms, the association of decreasing cholinergic activity with positive symptoms, and the covariance of positive and negative symptoms in the psychotic phase of schizophrenia, a model of (DA) dopaminergic/(ACh) cholinergic interactions in schizophrenia was recently formulated. It suggests that DA/ACh balance is of central importance in schizophrenic pathophysiology and that muscarinic ACh activity increases in an attempt to maintain this balance in the face of increasing DA activity that occurs in the psychotic phase of the illness. The model further suggests that the muscarinic system exerts a damping influence on the emergence of positive symptoms associated with DA hyperactivity, but that this compensatory increase in muscarinic activity is accompanied by an intensification of negative symptoms. In the present study, we tested two important postulates of this model. We tested the prediction that muscarinic activity is increased in schizophrenia by comparing the effect of biperiden, an antimuscarinic M-1 agent, on REM latency in 12 drug-free schizophrenic inpatients and matched normal controls. We found that biperiden caused a smaller increase in REM latency in schizophrenic patients, suggesting that muscarinic activity is increased in schizophrenia. We tested the prediction that an anticholinergic agent would increase positive symptoms and decrease negative symptoms by studying the effect of 8 mg of biperiden/day for 2 days on positive and negative symptoms (assessed by the BPRS) in 30 medication-free schizophrenic inpatients.(ABSTRACT TRUNCATED AT 250 WORDS)
Schizophrenia Research | 2013
M Deanna; Juan Bustillo; Wolfgang Gaebel; Raquel E. Gur; Stephan Heckers; Dolores Malaspina; Michael John Owen; Susan K. Schultz; Rajiv Tandon; Ming T. Tsuang; Jim Van Os; William T. Carpenter
Work on the causes and treatment of schizophrenia and other psychotic disorders has long recognized the heterogeneity of the symptoms that can be displayed by individuals with these illnesses. Further, researchers have increasingly emphasized the ways in which the severity of different symptoms of this illness can vary across individuals, and have provided evidence that the severity of such symptoms can predict other important aspects of the illness, such as the degree of cognitive and/or neurobiological deficits. Additionally, research has increasingly emphasized that the boundaries between nosological entities may not be categorical and that the comorbidity of disorders may reflect impairments in common dimensions of genetic variation, human behavior and neurobiological function. As such, it is critical to focus on a dimensional approach to the assessment of symptoms and clinically relevant phenomena in psychosis, so as to increase attention to and understanding of the causes and consequences of such variation. In the current article, we review the logic and justification for including dimensional assessment of clinical symptoms in the evaluation of psychosis in the Fifth Edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-5).
Schizophrenia Research | 2013
Stephan Heckers; M Deanna; Juan Bustillo; Wolfgang Gaebel; Raquel E. Gur; Dolores Malaspina; Michael John Owen; Susan K. Schultz; Rajiv Tandon; Ming T. Tsuang; Jim Van Os; William T. Carpenter
Schizophrenia spectrum disorders attract great interest among clinicians, researchers, and the lay public. While the diagnostic features of schizophrenia have remained unchanged for more than 100 years, the mechanism of illness has remained elusive. There is increasing evidence that the categorical diagnosis of schizophrenia and other psychotic disorders contributes to this lack of progress. The 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) continues the categorical classification of psychiatric disorders since the research needed to establish a new nosology of equal or greater validity is lacking. However, even within a categorical system, the DSM-5 aims to capture the underlying dimensional structure of psychosis. The domains of psychopathology that define psychotic disorders are presented not simply as features of schizophrenia. The level, the number, and the duration of psychotic signs and symptoms are used to demarcate psychotic disorders from each other. Finally, the categorical assessment is complemented with a dimensional assessment of psychosis that allows for more specific and individualized assessment of patients. The structure of psychosis as outlined in the DSM-5 may serve as a stepping-stone towards a more valid classification system, as we await new data to redefine psychotic disorders.
European Archives of Psychiatry and Clinical Neuroscience | 2012
Konstantinos N. Fountoulakis; Siegfried Kasper; Ole A. Andreassen; Pierre Blier; Ahmed Okasha; Emanuel Severus; Marcio Versiani; Rajiv Tandon; Hans-Jürgen Möller; Eduard Vieta
The current statement is a systematic review of the available data concerning the efficacy of medication treatment of bipolar disorder (BP). A systematic MEDLINE search was made concerning the treatment of BP (RCTs) with the names of treatment options as keywords. The search was updated on 10 March 2012. The literature suggests that lithium, first and second generation antipsychotics and valproate and carbamazepine are efficacious in the treatment of acute mania. Quetiapine and the olanzapine–fluoxetine combination are also efficacious for treating bipolar depression. Antidepressants should only be used in combination with an antimanic agent, because they can induce switching to mania/hypomania/mixed states/rapid cycling when utilized as monotherapy. Lithium, olanzapine, quetiapine and aripiprazole are efficacious during the maintenance phase. Lamotrigine is efficacious in the prevention of depression, and it remains to be clarified whether it is also efficacious for mania. There is some evidence on the efficacy of psychosocial interventions as an adjunctive treatment to medication. Electroconvulsive therapy is an option for refractory patients. In acute manic patients who are partial responders to lithium/valproate/carbamazepine, adding an antipsychotic is a reasonable choice. The combination with best data in acute bipolar depression is lithium plus lamotrigine. Patients stabilized on combination treatment might do worse if shifted to monotherapy during maintenance, and patients could benefit with add-on treatment with olanzapine, valproate, an antidepressant, or lamotrigine, depending on the index acute phase. A variety of treatment options for BP are available today, but still unmet needs are huge. Combination therapy may improve the treatment outcome but it also carries more side-effect burden. Further research is necessary as well as the development of better guidelines and algorithms for the step-by-step rational treatment.
Schizophrenia Research | 2013
Rajiv Tandon; Stephan Heckers; Juan Bustillo; M Deanna; Wolfgang Gaebel; Raquel E. Gur; Dolores Malaspina; Michael John Owen; Susan K. Schultz; Ming T. Tsuang; Jim Van Os; William T. Carpenter
Although catatonia has historically been associated with schizophrenia and is listed as a subtype of the disorder, it can occur in patients with a primary mood disorder and in association with neurological diseases and other general medical conditions. Consequently, catatonia secondary to a general medical condition was included as a new condition and catatonia was added as an episode specifier of major mood disorders in DSM-IV. Different sets of criteria are utilized to diagnose catatonia in schizophrenia and primary mood disorders versus neurological/medical conditions in DSM-IV, however, and catatonia is a codable subtype of schizophrenia but a specifier for major mood disorders without coding. In part because of this discrepant treatment across the DSM-IV manual, catatonia is frequently not recognized by clinicians. Additionally, catatonia is known to occur in several conditions other than schizophrenia, major mood disorders, or secondary to a general medical condition. Four changes are therefore made in the treatment of catatonia in DSM-5. A single set of criteria will be utilized to diagnose catatonia across the diagnostic manual and catatonia will be a specifier for both schizophrenia and major mood disorders. Additionally, catatonia will also be a specifier for other psychotic disorders, including schizoaffective disorder, schizophreniform disorder, brief psychotic disorder, and substance-induced psychotic disorder. A new residual category of catatonia not otherwise specified will be added to allow for the rapid diagnosis and specific treatment of catatonia in severely ill patients for whom the underlying diagnosis is not immediately available. These changes should improve the consistent recognition of catatonia across the range of psychiatric disorders and facilitate its specific treatment.
The Journal of Clinical Psychiatry | 2011
Rajiv Tandon
Schizophrenia is characterized by positive, negative, cognitive, disorganization, and mood symptoms. Antipsychotics are the mainstay in the pharmacologic treatment of schizophrenia. Findings concerning efficacy for positive symptoms and disorganization suggest no consistent differences among available antipsychotics, with the exception of clozapines superior efficacy for treatment-resistant schizophrenia. Efficacy for negative, depressive, and cognitive symptoms appears to be determined by (1) the extent to which reduction in positive symptoms brings about improvement in these other domains and (2) the extent to which extrapyramidal side effects (EPS) and anticholinergic effects (of the antipsychotic and of agents used to treat EPS) exacerbate them. Thus, the ability of antipsychotics to produce a potent antipsychotic effect without EPS and need for concomitant anticholinergic therapy yields multiple therapeutic benefits. In contrast to their broadly similar efficacy, antipsychotics differ markedly in their propensity to cause various adverse effects. Although second-generation antipsychotics (SGAs) have generally been believed to be associated with a lower risk of EPS but a higher risk of metabolic adverse effects than first-generation agents (FGAs), the substantial variation in these and other side effects among agents within both classes indicates that it is not clinically useful to make a categorical distinction between FGAs and SGAs. Choice of antipsychotic medication should be based on individual preference, prior treatment response and side effect experience, medical history and risk factors, and adherence history, with side effect profile a major determinant of antipsychotic choice.
Schizophrenia Research | 2013
Dolores Malaspina; Michael John Owen; Stephan Heckers; Rajiv Tandon; Juan Bustillo; Susan K. Schultz; M Deanna; Wolfgang Gaebel; Raquel E. Gur; Ming T. Tsuang; Jim Van Os; William T. Carpenter
Characterization of patients with both psychotic and mood symptoms, either concurrently or at different points during their illness, has always posed a nosological challenge and this is reflected in the poor reliability, low diagnostic stability, and questionable validity of DSM-IV Schizoaffective Disorder. The clinical reality of the frequent co-occurrence of psychosis and Mood Episodes has also resulted in over-utilization of a diagnostic category that was originally intended to only rarely be needed. In the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, an effort is made to improve reliability of this condition by providing more specific criteria and the concept of Schizoaffective Disorder shifts from an episode diagnosis in DSM-IV to a life-course of the illness in DSM-5. When psychotic symptoms occur exclusively during a Mood Episode, DSM-5 indicates that the diagnosis is the appropriate Mood Disorder with Psychotic Features, but when such a psychotic condition includes at least a two-week period of psychosis without prominent mood symptoms, the diagnosis may be either Schizoaffective Disorder or Schizophrenia. In the DSM-5, the diagnosis of Schizoaffective Disorder can be made only if full Mood Disorder episodes have been present for the majority of the total active and residual course of illness, from the onset of psychotic symptoms up until the current diagnosis. In earlier DSM versions the boundary between Schizophrenia and Schizoaffective Disorder was only qualitatively defined, leading to poor reliability. This change will provide a clearer separation between Schizophrenia with mood symptoms from Schizoaffective Disorder and will also likely reduce rates of diagnosis of Schizoaffective Disorder while increasing the stability of this diagnosis once made.