Lamotrigine augmentation of serotonin re-uptake inhibitors in obsessive-compulsive disorder

Therapies for obsessive-compulsive disorder: Current state of the art and perspectives for approaching treatment-resistant patients

Even though obsessive compulsive disorder (OCD) is one of the ten most disabling diseases according to the WHO, only 30-40% of patients suffering from OCD seek specialized treatment. The currently available psychotherapeutic and pharmacological approaches, when properly applied, prove ineffective in about 10% of cases. The use of neuromodulation techniques, especially Deep Brain Stimulation, is highly promising for these clinical pictures and knowledge in this domain is constantly evolving. The aim of this paper is to provide a summary of the current knowledge about OCD treatment, while also discussing the more recent proposals for defining resistance.

Treatment-resistant OCD: Pharmacotherapies in adults

Serotonin reuptake inhibitor (SRI) medications are well established as first-line pharmacotherapeutic treatment for Obsessive-Compulsive Disorder (OCD). However, despite the excellent safety profile and demonstrated efficacy of these medications, a substantial proportion of individuals with OCD fail to attain sufficient benefit from SRIs. In this narrative review, we discuss clinical features of OCD that have been associated with poorer response to SRIs, and we present pharmacotherapeutic interventions that have been explored as augmenting or alternative treatments for treatment-resistant OCD. We additionally highlight non-SRI interventions for OCD that are currently under investigation. Pharmacotherapeutic interventions were identified via expert consensus. To assess the evidence base for individual pharmacotherapies, targeted searches for relevant English-language publications were performed on standard biomedical research databases, including MEDLINE. Information relevant to ongoing registered clinical trials in OCD was obtained by search of ClinicalTrials.gov. Pharmacotherapies are grouped for review in accordance with the general principles of Neuroscience-based Nomenclature (NbN). Clinical features of OCD that may suggest poorer response to SRI treatment include early age of onset, severity of illness, duration of untreated illness, and the presence of symmetry/ordering or hoarding-related symptoms. Based on evolving pathophysiologic models of OCD, diverse agents engaging serotonin, dopamine, norepinephrine, glutamate, and anti-inflammatory pathways have been explored as alternative or adjunctive therapies for treatment-resistant OCD and have at least preliminary evidence of efficacy. Medications with dopamine antagonist activity remain the most robustly evidence-based of augmenting interventions, yet dopamine antagonists benefit only a minority of those who try them and carry elevated risks of adverse effects. Interventions targeting glutamatergic and anti-inflammatory pathways are less well evidenced, but may offer more favorable benefit to risk profiles. Ongoing research should explore whether specific interventions may benefit individuals with particular features of treatment-resistant OCD.

Specialty knowledge and competency standards for pharmacotherapy for adult obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) affects approximately one person in 40 and causes substantial suffering. Evidence-based treatments can benefit many; however, optimal treatment can be difficult to access. Diagnosis is frequently delayed, and pharmacological and psychotherapeutic interventions often fail to follow evidence-based guidelines. To ameliorate this distressing situation, the International OCD Accreditation Task Force of the Canadian Institute for Obsessive-Compulsive Disorders has developed knowledge and competency standards for specialized treatments for OCD through the lifespan. These are foundational to evidence-based practice and will form the basis for upcoming ATF development of certification/accreditation programs. Here, we present specialty standards for the pharmacological treatment of adult OCD. We emphasize the importance of integrating pharmacotherapy with clear diagnosis, appreciation of complicating factors, and evidence-based cognitive behavioral therapy. Clear evidence exists to inform first- and second-line pharmacological treatments. In disease refractory to these initial efforts, multiple strategies have been investigated, but the evidence is more equivocal. These standards summarize this limited evidence to give the specialist practitioner a solid basis on which to make difficult decisions in complex cases. It is hoped that further research will lead to development of a clear, multi-step treatment algorithm to support each step in clinical decision-making.

Pharmacotherapeutic Strategies and New Targets in OCD

Effective pharmacological and psychotherapeutic treatments are well established for obsessive-compulsive disorder (OCD). Serotonin reuptake inhibitors (SRIs) are first-line treatment and are of benefit to about half of patients. Augmentation of SRI treatment with low-dose neuroleptics is an evidence-based second-line strategy. Specialty psychotherapy is also used as both first-line and second-line treatment and can benefit many. However, a substantial number of patients do not respond to these treatments. New alternatives are urgently needed. This review summarizes evidence for these established pharmacotherapeutic strategies, and for others that have been investigated in refractory disease but are not supported by the same level of evidence. We focus on three neurotransmitter systems in the brain: serotonin, dopamine, and glutamate. We summarize evidence from genetic, neuroimaging, animal model, and other lines of investigation that probe these three systems in patients with OCD. We also review recent work on predictors of response to current treatments. While many studies suggest abnormalities that may provide insight into the pathophysiology of the disorder, most studies have been small, and non-replication of reported findings has been common. Nevertheless, the gradual accrual of evidence for neurotransmitter dysregulation may in time lead the way to new pharmacological strategies.

Lamotrigine Uses in Psychiatric Practice

BACKGROUND

Lamotrigine (LAM), an antiepileptic, with panoply of indications and uses in neurology, is FDA approved, in psychiatry, for bipolar prophylaxis. Apart from this indication, trend of its use in psychiatry is on the rise addressing a multitude of disorders.

STUDY QUESTION

LAM remains one of only few psychotropic drugs with antiglutamate activity. This might render LAM a potential therapeutic option in treatment-resistant major psychiatric disorders. We reviewed LAM pharmacology and its diverse indications while examining the extant evidence.

METHODS

EMBASE, Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane Database of Systemic Reviews were searched for all relevant studies up to date of June 2016.

RESULTS

Sound evidence supports use of LAM for acute bipolar depression and prophylaxis, treatment-resistant schizophrenia, treatment-resistant obsessive-compulsive disorder, posttraumatic stress disorder, depersonalization disorder, and affective dysregulation and behavioral dyscontrol domains of borderline personality disorder. Less compelling evidence is present for use in behavioral and psychological symptoms of dementia and neuropsychiatric sequelae of traumatic brain injury. No evidence supports use in autism spectrum disorder or acute unipolar depression.

CONCLUSIONS

LAM is an important addition to the psychopharmacological armamentarium. Level of evidence supporting the use of LAM in off-label indications is highly variable, and hence, sound clinical judgment is necessary for its proper use and placement in real-life psychiatric practice and psychopharmacotherapy algorithms.

Epilepsy and concomitant obsessive-compulsive disorder

People with epilepsy (PWE) often suffer psychiatric symptoms which can impact them more than seizures. Affective and psychotic disorders are well recognized as occurring more frequently in PWE than the general population. Less is known about obsessive-compulsive disorder (OCD) in PWE, despite it being as disabling and distressing. We sought to explore the association between epilepsy and OCD with casereports by identifying ten PWE and concomitant OCD. Demographics, seizure classification, neurological, surgical, psychiatric and psychological treatment as well as quality of life were examined. A detailed analysis was performed for three of them, to explore the lived-experience of patients with the two conditions. This is followed by a discussion of how treatment for co-morbid epilepsy and OCD can be appropriately tailored to be patient specific and provide the greatest potential for improvement.

HCN Channel Targets for Novel Antidepressant Treatment

Major depressive disorder (MDD) is a chronic and potentially life threatening illness that carries a staggering global burden. Characterized by depressed mood, MDD is often difficult to diagnose and treat owing to heterogeneity of syndrome and complex etiology. Contemporary antidepressant treatments are based on improved monoamine-based formulations from serendipitous discoveries made > 60 years ago. Novel antidepressant treatments are necessary, as roughly half of patients using available antidepressants do not see long-term remission of depressive symptoms. Current development of treatment options focuses on generating efficacious antidepressants, identifying depression-related neural substrates, and better understanding the pathophysiological mechanisms of depression. Recent insight into the brain's mesocorticolimbic circuitry from animal models of depression underscores the importance of ionic mechanisms in neuronal homeostasis and dysregulation, and substantial evidence highlights a potential role for ion channels in mediating depression-related excitability changes. In particular, hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are essential regulators of neuronal excitability. In this review, we describe seminal research on HCN channels in the prefrontal cortex and hippocampus in stress and depression-related behaviors, and highlight substantial evidence within the ventral tegmental area supporting the development of novel therapeutics targeting HCN channels in MDD. We argue that methods targeting the activity of reward-related brain areas have significant potential as superior treatments for depression.

Glutamate-Modulating Drugs as a Potential Therapeutic Strategy in Obsessive-Compulsive Disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a mental disease commonly associated with severe distress and impairment of social functioning. Serotonin reuptake inhibitors and/or cognitive behavioural therapy are the therapy of choice, however up to 40% of patients do not respond to treatment. Glutamatergic signalling has also been implicated in OCD. The aim of the current study was to review the clinical evidence for therapeutic utility of glutamate-modulating drugs as an augmentation or monotherapy in OCD patients.

METHODS

We conducted a search of the MEDLINE database for clinical studies evaluating the effect of glutamate-modulating drugs in OCD.

RESULTS

Memantine is the compound most consistently showing a positive effect as an augmentation therapy in OCD. Anti-convulsant drugs (lamotrigine, topiramate) and riluzole may also provide therapeutic benefit to some OCD patients. Finally, ketamine may be of interest due to its potential for a rapid onset of action.

CONCLUSION

Further randomized placebo-controlled trials in larger study populations are necessary in order to draw definitive conclusions on the utility of glutamate-modulating drugs in OCD. Furthermore, genetic and epigenetic factors, clinical symptoms and subtypes predicting treatment response to glutamate-modulating drugs need to be investigated systematically.

Hoarding Symptoms Respond to Treatment for Rapid Cycling Bipolar II Disorder

Although some studies have reported a relationship between hoarding and bipolar disorder, we are unaware of any previous description of how they may interact with each other and how they should be managed appropriately. A 48-year-old male depressed patient with hoarding symptoms and obsessive-compulsive disorder (OCD) was diagnosed with bipolar II disorder after 2 hypomanic episodes. The patient was treated unsuccessfully with different high-dose serotonin reuptake inhibitors and atypical antipsychotics, maintaining a pattern of 6 to 8 discrete, but severe, depressive episodes each year, always in association with a drastic worsening of his OCD and hoarding symptoms. T.he patient did not improve until the dose of the serotonin reuptake inhibitor was decreased and a combination of lamotrigine and methylphenidate was initiated. On this treatment regimen, the patient did not show clinically significant levels of depression or hoarding or other OCD symptoms. This case suggests that, in some patients, (1) hoarding-related cognitions and behaviors may be a part of bipolar depression, (2) the episodic nature of rapid cycling bipolar II disorder may protect against the development of severe clutter, and (3) treatment focusing on bipolar depression (eg, lamotrigine plus methylphenidate) may result in an improvement of hoarding symptoms when these are present in patients with rapid cycling bipolar II disorder.

Glutamatergic agents for OCD and related disorders

Pharmacotherapy remains inadequate for many patients with OCD; there is an urgent need for alternative pharmacological strategies. Convergent evidence suggests imbalance in glutamate, the brain's primary excitatory neurotransmitter, in some patients. This has motivated interest in glutamate modulators in patients who are unresponsive to standard pharmacotherapeutic approaches. While no glutamate modulator can be considered proven as an efficacious treatment of OCD, promising suggestions of benefit have been reported for memantine and riluzole. The evidence is thinner for N-acetylcysteine, but this agent's low cost and benign side effect profile make it a reasonable consideration in certain patients. Intriguing research on D-cycloserine and ketamine suggest potential benefit as well. It is notable that these agents all work by different, and in some cases opposite, mechanisms; this suggests that we have much to learn about the role of glutamate dysregulation in the etiology of OCD, and of glutamate modulators in its treatment.

Glutamate modulators in the treatment of obsessive-compulsive disorder

Established treatments for obsessive-compulsive disorder (OCD) are of benefit in approximately 3 of every 4 patients, but refractory disease remains distressingly common, and many treatment responders continue to experience considerable morbidity. This motivates a search for new insights into pathophysiology that may inform novel treatment strategies. Much recent work has focused on the neurotransmitter glutamate. Several lines of neurochemical and genetic evidence suggests that glutamate dysregulation may contribute to OCD, although much remains unclear. The off-label use of a number of pharmacological agents approved for other indications has been investigated in refractory OCD. We summarize investigations of memantine, riluzole, ketamine, D-cycloserine, glycine, N-acetylserine, topiramate, and lamotrigine. Evidence exists for benefit from each of these in some patients; though none has been proven effective with sufficient clarity to be considered part of standard care, these agents are options in individuals whose symptoms are refractory to better-established therapeutic strategies.

Role of lamotrigine augmentation in treatment-resistant obsessive compulsive disorder: a retrospective case review from South Asia

BACKGROUND

Resistance to pharmacotherapy is one of the major challenges in the management of obsessive-compulsive disorder (OCD). OCD being a quite prevalent disorder, this resistance adds to the disability. Different strategies are being employed to counter this resistance, one of them being augmentation with glutamatergic modulators. Lamotrigine is being used for same since the recent past with mixed results.

OBJECTIVE

The aim was to study the role of lamotrigine augmentation in serotonin reuptake inhibitor (SRI) resistant OCD patients.

METHODOLOGY AND RESULTS

This study was carried by studying the case sheets of SRI resistant cases having already completed the treatment. A total of 22 cases sheets over 2 years met the study criteria with a mean age of mean age of 34.14 years. Over a period of 16 weeks, with a mean lamotrigine dose of 150 mg/day, 20 out of 22 patients had shown a significant response. The mean decrease in Yale-Brown Obsessive Compulsive Scale score was 67.23% with a baseline score of 28.87. There was a similar change on different domains of World Health Organization quality of life (P = 0.00564).

CONCLUSION

Lamotrigine augmentation to on-going treatment with SRIs may be an effective move in case of SRI resistant OCD patients.

Pharmacological treatment of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) affects up to 2.5% of the population of the course of a lifetime and produces substantial morbidity. Approximately 70% of patients can experience significant symptomatic relief with appropriate pharmacotherapy. Selective serotonin reuptake inhibitors are the mainstay of pharmacological treatment. These drugs are typically used at higher doses and for longer periods than in depression. Proven second-line treatments include the tricyclic clomipramine and the addition of low-dose neuroleptic medications. OCD refractory to available treatments remains a profound clinical challenge.

Obsessive compulsive disorder and the glutamatergic system

PURPOSE OF REVIEW

Evidence-based pharmacological interventions for obsessive compulsive disorder (OCD) are targeted mainly at the serotonergic and dopaminergic pathways, and are not always effective. It is timely to review the growing evidence from animal models and clinical research (e.g., brain imaging, genetics) on the role of the glutamatergic system in OCD.

RECENT FINDINGS

Emerging evidence from both animal models and clinical research (including brain imaging, neurogenetics) supports the glutamatergic system as a potential target for pharmacotherapy in OCD. Although there have been relatively few randomized controlled trials of glutamatergic agents in pediatric or adult OCD to date, there is some work on riluzole, memantine, ketamine, topiramate, lamotrigine, N-acetylcysteine, and D-cycloserine.

SUMMARY

Given the need for more efficacious treatments in OCD, and given emergent findings on the role of the glutamatergic system in this disorder, there is a need for additional pharmacotherapy trials on glutamatergic agents in OCD. Possible research designs for such trials might include stand-alone approaches, pharmacotherapy augmentation, or psychotherapy augmentation.

A case series of patients with lamotrigine toxicity at one center from 2003 to 2012

INTRODUCTION

Lamotrigine is a phenyltriazine compound that inhibits voltage-gated sodium channels, decreasing release of glutamate and aspartate, and inhibits serotonin, norepinephrine and dopamine reuptake. Reports of toxicity in the literature are limited to case reports and primarily involve coingestants. This case series is intended to report the clinical manifestations of lamotrigine toxicity.

METHODS

This retrospective case series from 2003 to 2012 studies the effects of lamotrigine toxicity when not confounded by coingestants. Admission records at an inpatient toxicology center were reviewed for lamotrigine-only exposure based on history with supporting laboratory data when available. After identification, these charts were reviewed again to characterize vital signs, neurological examination findings, specific laboratory and electrocardiography parameters, and complications.

RESULTS

Fifty-seven patients were identified with possible lamotrigine toxicity. Nine patients, including three toddlers, had lamotrigine-only ingestions. Three of these patients had seizures, four were hypertensive, five were tachycardic, and four experienced tachypnea. Mental status was altered in all nine (depressed (n = 4), agitated (n = 5) or both (n = 3)). Five patients were hyperreflexic and experienced intermittent myoclonus, and two had inducible clonus. On electrocardiogram, two patients experienced QRS prolongation (114-116 ms), and four had QTc prolongation (463-586 ms). No patient had life-threatening symptoms or signs. Serum levels of lamotrigine were available in seven patients, and averaged 35.4 mg/L (17-90 mg/L). The therapeutic range for sLTG is 3-14 mg/L.

CONCLUSIONS

Lamotrigine toxicity manifested with minor-moderate neurologic and/or electrocardiographic effects. Toxicity reflects the known pharmacologic actions of lamotrigine: serotonin, norepinephrine and dopamine reuptake inhibition, and sodium channel blockade.

Lamotrigine augmentation of serotonin reuptake inhibitors in severe and long-term treatment-resistant obsessive-compulsive disorder

The treatment recommendations in obsessive-compulsive disorder (OCD) after lack of response to selective serotonin reuptake inhibitors (SSRIs) include augmentation with other drugs, particularly clomipramine, a more potent serotonin reuptake inhibitor (SRI), or antipsychotics. We present two cases of response to lamotrigine augmentation in treatment-refractory OCD; each received multiple SRI trials over a >10-year period. The first patient had eleven years of treatment with multiple combinations including clomipramine and SSRIs. She had a >50% decrease of Y-BOCS (from 29 to 14) by augmenting paroxetine (60 mg/day) with lamotrigine (100 mg/day). The second patient had 22 years of treatment with multiple combinations, including combinations of SSRIs with clomipramine and risperidone. She had an almost 50% decrease of Y-BOCS (from 30 to 16) and disappearance of tics by augmenting clomipramine (225 mg/d) with lamotrigine (200 mg/day). These two patients were characterized by lack of response to multiple treatments, making a placebo response to lamotrigine augmentation unlikely. Prospective randomized trials in treatment-resistant OCD patients who do not respond to combinations of SSRIs with clomipramine and/or antipsychotics are needed, including augmentation with lamotrigine. Until these trials are available, our cases suggest that clinicians may consider lamotrigine augmentation in such treatment-resistant OCD patients.

N-acetylcysteine add-on treatment in refractory obsessive-compulsive disorder: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

This study aimed to evaluate the efficacy and safety of N-acetylcysteine, a glutamate-modulating agent, in patients with treatment-refractory obsessive-compulsive disorder as an adjunct to serotonin reuptake inhibitor treatment.

METHODS

Forty-eight patients (36 women; mean ± SD age, 30.93 ± 4.99) with obsessive-compulsive disorder who failed to respond to a course of serotonin reuptake inhibitor treatment were randomized to a 12-week intervention period of N-acetylcysteine (up to 2400 mg/d) or placebo. Primary outcome measures were the change in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score from baseline to end point and the rate of full response in each group at the end of trial. Full response was defined as 35% or greater reduction in Y-BOCS score from baseline.

RESULTS

Changes of Y-BOCS score were different over time (P < 0.001) and between groups (P < 0.001). N-acetylcysteine-assigned patients showed significantly improved mean Y-BOCS score (P = 0.003) and Clinical Global Impression-Severity of Illness scale score (P = 0.01) but not Clinical Global Impression-Improvement scale score at study end point. Of the patients in the N-acetylcysteine group, 52.6% were full responders at the end of the study, which was significantly higher than 15% of the patients in the placebo group (P = 0.013).

CONCLUSION

This trial suggests that N-acetylcysteine may be a safe and effective option to augment standard treatment in patients with refractory obsessive-compulsive disorder.

Lamotrigine augmentation of serotonin reuptake inhibitors in treatment-resistant obsessive-compulsive disorder: a double-blind, placebo-controlled study

The present 16-week double-blind, randomized, placebo-controlled trial had the aim to explore the efficacy of lamotrigine add-on pharmacotherapy on clinical symptomatology and cognitive functioning in a sample of patients with treatment-resistant obsessive-compulsive disorder (OCD) receiving serotonin reuptake inhibitors (SRIs). After clinical and neurocognitive assessments, patients were randomly allocated to receive, in a double-blind design, 100 mg/day of lamotrigine or a placebo. A final sample of 33 patients completed the study. The results obtained indicate that lamotrigine added to stable SRI treatment substantially improved obsessive-compulsive (Yale-Brown Obsessive Compulsive Scale: obsessions, p < 0.0001; compulsions, p < 0.0001; total score, p < 0.0001), and affective symptoms (Hamilton Rating Scale for Depression p < 0.0001). Regarding cognitive functions, improvement was observed only in Semantic Fluency (p = 0.004). The findings provide evidence that lamotrigine augmentation of SRI treatment is well tolerated and may be proposed as an effective therapeutic strategy to improve outcome in treatment-resistant OCD.

Lamotrigine in the treatment of unipolar depression with and without comorbidities: a literature review

To review the available data behind the use of lamotrigine in unipolar depression and common comorbid conditions. A PubMed based literature review was conducted using keywords related to lamotrigine, depression, anxiety, post traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), and personality disorders. A large number of trials using lamotrigine for unipolar depression and various comorbid conditions were reviewed. A major limitation behind the majority of studies was a limited course of the treatment phase. The most robust data was found among studies that followed patients for over 8 weeks, and used higher dosages. Patients with comorbid anxiety states appeared to benefit. Patients with borderline personality disorder also appeared to benefit. The benefits of lamotrigine in unipolar depression have been inconsistently noted in a number of studies. This is due in part to short treatment phases, atypical domains of benefit and different patient populations across studies. Patients with more treatment-resistance, comorbid anxiety and borderline personality disorder may be more able to benefit from lamotrigine.

[Bipolar disorders and comorbid anxiety: prognostic impact and therapeutic challenges]

INTRODUCTION

Anxiety disorders are among the main psychiatric conditions co-occuring with bipolar disorders. Many clinical and epidemiological studies have found much higher prevalence rates of generalized anxiety disorder, social phobia, obsessive-compulsive disorder, panic disorder and post-traumatic stress disorder in bipolar patients than in the general population, regardless of age. In the National Comorbidity Survey for instance, the diagnosis of at least one anxiety disorder was made for nearly 90% of bipolar subjects. Several issues arise from this high comorbidity, such as the way anxiety disorders alter the course and prognosis of the mood disorder, and challenge typical therapeutic strategies. This article reviews data on clinical and therapeutical significance of such comorbidity.

LITERATURE FINDINGS

Many studies point out the poorer outcome for bipolar patients with co-occurring anxiety symptoms: apart from the alarming increase of suicidal ideas and suicide attempts, authors have found a shorter duration of euthymia, more comorbid addictions, mixed states and rapid cycling, and lower response to treatments. This is the reason why monitoring the suicidal risk in those bipolar patients with co-occurring anxiety disorders is of critical importance. From a physiopathological standpoint, the precise links between both pathologies remains unclear. The frequency of this comorbidity and its significance on long term prognosis stands in sharp contrast with the very few therapeutic studies conducted in this indication so far. Pharmacological approaches are strongly limited by the risk of mood switching under antidepressants and drug dependence on anxiolytics such as benzodiazepines. Nevertheless, there is emerging evidence of the interest of atypical antipsychotics such as olanzapine and mood stabilisers such as lamotrigine to control anxiety symptoms in bipolar patients. There is weaker evidence for other molecules. Taking into account other therapeutic approaches than the pharmacological approach appears accurate. Psychosocial interventions such as cognitive-behavioral therapies or psychoeducation appear essential to improve in a correct way the global functioning and quality of life of these patients.

The role of glutamate signaling in the pathogenesis and treatment of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a common and often debilitating neuropsychiatric condition characterized by persistent intrusive thoughts (obsessions), repetitive ritualistic behaviors (compulsions) and excessive anxiety. While the neurobiology and etiology of OCD has not been fully elucidated, there is growing evidence that disrupted neurotransmission of glutamate within corticalstriatal-thalamocortical (CSTC) circuitry plays a role in OCD pathogenesis. This review summarizes the findings from neuroimaging, animal model, candidate gene and treatment studies in the context of glutamate signaling dysfunction in OCD. First, studies using magnetic resonance spectroscopy are reviewed demonstrating altered glutamate concentrations in the caudate and anterior cingulate cortex of patients with OCD. Second, knockout mouse models, particularly the DLGAP3 and Sltrk5 knockout mouse models, display remarkably similar phenotypes of compulsive grooming behavior associated with glutamate signaling dysfunction. Third, candidate gene studies have identified associations between variants in glutamate system genes and OCD, particularly for SLC1A1 which has been shown to be associated with OCD in five independent studies. This converging evidence for a role of glutamate in OCD has led to the development of novel treatment strategies involving glutamatergic compounds, particularly riluzole and memantine. We conclude the review by outlining a glutamate hypothesis for OCD, which we hope will inform further research into etiology and treatment for this severe neuropsychiatric condition.

Glutamate abnormalities in obsessive compulsive disorder: neurobiology, pathophysiology, and treatment

Obsessive compulsive disorder is prevalent, disabling, incompletely understood, and often resistant to current therapies. Established treatments consist of specialized cognitive-behavioral psychotherapy and pharmacotherapy with medications targeting serotonergic and dopaminergic neurotransmission. However, remission is rare, and more than a quarter of OCD sufferers receive little or no benefit from these approaches, even when they are optimally delivered. New insights into the disorder, and new treatment strategies, are urgently needed. Recent evidence suggests that the ubiquitous excitatory neurotransmitter glutamate is dysregulated in OCD, and that this dysregulation may contribute to the pathophysiology of the disorder. Here we review the current state of this evidence, including neuroimaging studies, genetics, neurochemical investigations, and insights from animal models. Finally, we review recent findings from small clinical trials of glutamate-modulating medications in treatment-refractory OCD. The precise role of glutamate dysregulation in OCD remains unclear, and we lack blinded, well-controlled studies demonstrating therapeutic benefit from glutamate-modulating agents. Nevertheless, the evidence supporting some important perturbation of glutamate in the disorder is increasingly strong. This new perspective on the pathophysiology of OCD, which complements the older focus on monoaminergic neurotransmission, constitutes an important focus of current research and a promising area for the ongoing development of new therapeutics.

Psychotherapy and medication management strategies for obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic anxiety disorder. While medication and psychotherapy advances have been very helpful to patients, many patients do not respond adequately to initial trials of serotonergic medication or cognitive-behavioral therapy (CBT) and require multiple treatment trials or combination therapies. Comorbidity may also influence treatment response. The role of streptococcal infections in pediatric OCD has become an area of intense scrutiny and controversy. In this article, current treatment methods for OCD will be reviewed, with special attention to strategies for treating OCD in children and in patients with comorbid tic disorders. Alternative psychotherapy strategies for patients who are highly anxious about starting CBT, such as cognitive therapy or augmentation with D-cycloserine, will be reviewed. Newer issues regarding use of antibiotics, neuroleptics, and glutamate modulators in OCD treatment will also be explored.

Lamotrigine administration in panic disorder with agoraphobia

Several anticonvulsants, although as yet not lamotrigine (LTG), have been found useful in the treatment of panic disorder with (PDA) or without agoraphobia. We administered LTG (200 mg/d) to 4 outpatients with PDA, as an augmentation therapy (3 patients with chronic and severe agoraphobia) or monotherapy (1 drug-naive patient with first-onset PDA) in a 14-week trial. The patient under LTG monotherapy improved significantly, whereas PDA symptoms in 2 of the other patients improved to some extent.

Lamotrigine augmentation in schizophrenia and schizoaffective patients with obsessive-compulsive symptoms

Obsessive-compulsive symptoms (OCS) are clinically important phenomena in schizophrenia patients. Lamotrigine has a modulating effect on glutamatergic neurotransmission relevant to pathophysiology of both schizophrenia and OCD. Efficacy and tolerability of lamotrigine in schizophrenia and schizoaffective patients with comorbid OCS were evaluated. In an 8-week, open-label trial, lamotrigine (25 mg/day for 1 week, 50 mg for 2 weeks, 100 mg for 2 weeks, 200 mg for 3 weeks) was added to ongoing psychotropic drug regimens in schizophrenia (N = 5) and schizoaffective disorder (N = 6) patients with clinically significant OCS [Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score > 16]. The Y-BOCS score for nine completers decreased significantly from baseline to week 8 (22.9 +/- 6.1 vs 17.4 +/- 3.6; t = 2.33, df = 1, P = 0.033). Five patients, all with schizoaffective disorder, were responders (>or=35% decrease in Y-BOCS score). No significant changes were detected in schizophrenia symptom severity. Depressive symptoms, assessed with the Calgary Depression Rating Scale, improved significantly (6.4 +/- 1.5 vs 4.0 +/- 2.5; t = 3.19, df = 1, P = 0.013); this change positively correlated with OCS improvement (r = 0.69, P = 0.04). Lamotrigine was safe and well tolerated. Explicit evaluation of therapeutic efficacy of adjunctive lamotrigine in schizoaffective disorder patients with comorbid OCS merits further investigation.

Lamotrigine as an augmentation agent in treatment-resistant obsessive-compulsive disorder: a case report

Obsessive-compulsive disorder (OCD) is a relatively common, often chronic and disabling disorder with high rates of partial and/or absent response to standard, recommended treatments. We report a case of treatment-resistant OCD that was successfully treated with a pharmacological augmentation of lamotrigine plus clomipramine. The patient, a 59-year-old woman, was on a stable dose of clomipramine (225 mg/day) when she was started on lamotrigine (up to 150 mg/day). After 10 weeks of this treatment, her clinical condition remarkably improved, as indicated by a significant decrease of the Yale-Brown Obsessive-Compulsive Scale. This case suggests some preliminary evidence that the addition of glutamatergic agent lamotrigine may be useful in treatment-resistant OCD. However, further controlled studies are needed to support this finding.

Does gabapentin lead to early symptom improvement in obsessive-compulsive disorder?

OBJECTIVE

The aim of this study was to compare efficacy of fluoxetine alone and co-administration of gabapentin and fluoxetine in patients with obsessive compulsive disorder (OCD).

METHODS

Forty outpatients with a DSM-IV diagnosis of OCD were randomized to open label treatment, 20 of whom were treated with fluoxetine alone and the remaining 20 with fluoxetine plus gabapentin during 8 weeks. The severity was assessed by Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and Clinical Global Impression (CGI).

RESULTS

Final CGI-I and Y-BOCS scores were not significantly different in both groups. However, in repeated measures ANOVA, compared to fluoxetine group, we found significantly a better improvement in the fluoxetine plus gabapentin group at week 2 by means of YBOCS and CGI-I scores. Comparisons on weeks 4, 6 and 8 revealed no statistical differences between the groups. There was no significant difference of adverse effects between two groups.

CONCLUSIONS

Adding gabapentin to fluoxetine in the treatment of OCD seems to shorten the time to onset of fluoxetine's anti-obsessive effect without a significant increase in adverse effects. In order to accelerate the clinical response, co-administration of fluoxetine and gabapentin may be a preferable strategy. On the other hand, further controlled studies are needed to support this finding.

Glutamatergic Synaptic Dysfunction and Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric condition estimated to afflict 1-3% of the world population. The estimated financial impact in the treatment and management of OCD is in the billions of dollars annually in the US alone. At present there is a marked lack of evidence on the specific causes of OCD. Current hypotheses largely focus on the serotonin (5-HT) system on the basis of the effectiveness of selective serotonin reuptake inhibitors (SSRIs) in alleviating symptoms of patients with OCD, yet a considerable fraction of patients are non-responsive or minimally responsive to these agents. Despite this fact, SSRIs have remained the primary pharmacological treatment avenue for OCD. In recent years, multiple lines of evidence have implicated glutamatergic synaptic dysfunction within the cortico-striatal-thalamo-cortical (CSTC) brain circuit in the etiology of OCD and related disorders, thereby prompting intensified effort in the development and evaluation of agents that modulate glutamatergic neurotransmission for the treatment of OCD. With this in mind, here we review the following topics with respect to synaptic dysfunction and the neural circuitry underlying OCD: (1) evidence supporting the critical involvement of the CSTC circuit, (2) genetic studies supporting the involvement of glutamatergic dysfunction, (3) insights from genetic animal models of OCD, and (4) preliminary findings with glutamatergic neurotransmission-modulating agents in the treatment of OCD. Given the putative mechanistic overlap between OCD and the broader OC-spectrum of disorders, unraveling the synaptic basis of OCD has potential to translate into more effective treatments for an array of poorly understood human disorders.

The role of anticonvulsant drugs in anxiety disorders: a critical review of the evidence

Antiepileptic drugs (AEDs) have been successfully used in the treatment of mood disturbances, leading clinicians and researchers to investigate their use in other psychiatric disorders. This article reviews the literature about the potential efficacy of AEDs in anxiety disorders. An updated MEDLINE search (January 1970 to September 2006) using the terms "panic disorder," "agoraphobia," "posttraumatic stress disorder," "obsessive-compulsive disorder," "generalized anxiety disorder," "social phobia," "phobia," "carbamazepine," "phenobarbital," "phenytoin," "valproate," "lamotrigine," "topiramate," "vigabatrin," "tiagabine," "gabapentin," "levetiracetam," and "pregabalin" showed more than 70 articles and 38 published studies. Only articles published in English were reviewed. We have assigned level 1 of evidence to meta-analysis and replicated randomized controlled trials, level 2 to at least 1 randomized controlled trial, level 3 to uncontrolled trials with 10 or more subjects, and level 4 to anecdotal case reports. The strongest evidence has been demonstrated for pregabalin in social phobia and generalized anxiety disorder, lamotrigine in posttraumatic stress disorder, and gabapentin in social anxiety. The available data about gabapentin in panic disorder are somewhat mixed, and more definitive conclusion would require additional studies. This review suggests that AEDs can be an alternative treatment in some anxiety disorders. Further investigation is needed to determine in what circumstances they should be used in individuals who are partially responsive or nonresponsive to conventional therapy.

An update on the pharmacological treatment of obsessive-compulsive disorder

The purpose of this article is to introduce the reader to an updated evidence-based drug treatment algorithm to be employed in patients with obsessive-compulsive disorder (OCD). Relevant studies were identified through a comprehensive review and classified according to the type of patients enrolled, the quality of the study design and the invasiveness, availability and complexity of the therapeutic approach. When ineffective, therapeutic trials with first-line strategies (such as the selective serotonin re-uptake inhibitors [SSRIs] and venlafaxine) should be followed by treatment approaches such as clomipramine, augmentation with antipsychotics or pindolol, SSRI megadoses or cognitive behavioral therapy. These therapeutic strategies are expected to help most patients with OCD. Additional approaches include intravenous clomipramine, oral morphine, 'heroic drug strategies', deep brain stimulation and functional neurosurgery. Independent studies are urgently needed to help identify the most promising drug treatment sequences for OCD.

The treatment of generalized anxiety disorder with pregabalin, an atypical anxiolytic

A constellation of pharmacologic treatments for generalized anxiety disorder (GAD) have been developed over the past five decades, although each has a number of potential drawbacks in clinical practice. This review addresses one potentially new pharmacologic treatment for generalized anxiety disorder, the gamma-aminobutyric acid analogue pregabalin. We review the mechanism of action, and pharmacokinetic and pharmacodynamic properties of pregabalin as well as the results of 5 double-blind, placebo-controlled trials of pregabalin in the treatment of generalized anxiety disorder (GAD). Based entirely on data from these industry-sponsored (Pfizer), multi-site clinical trials in patients with GAD, pregabalin appears to be generally well tolerated and has rapid onset of action (approximately 1 week), comparable efficacy to benzodiazepines and lower discontinuation rates compared with other pharmacologic treatments. Thus in GAD, a disorder that is often suboptimally responsive to traditional psychotherapeutic and psychopharmacologic interventions - secondary to poor efficacy, tolerability, and/or side-effects - pregabalin may have a primary role in GAD patients, especially in those with certain psychiatric comorbidities or individuals who are on multi-drug regimens for medical comorbidities.

Topiramate augmentation in treatment-resistant obsessive-compulsive disorder: a retrospective, open-label case series

Serotonin reuptake inhibitors (SRIs) are considered first-line treatments for obsessive-compulsive disorder (OCD). Many patients achieve some response but remain symptomatic despite an adequate SRI trial. Recent neuroimaging data found abnormally high glutamatergic concentrations in children with OCD. Following selective serotonin reuptake inhibitor (SSRI) treatment, a decrease in OCD symptom severity was associated with a decrease in caudate glutamatergic concentrations. We initiated an investigation of adjunctive topiramate (an anticonvulsant agent with glutamatergic properties) in the treatment of patients with OCD who were partially or nonresponsive to SRI treatment. Sixteen consecutive outpatients with OCD (mean age = 41.1 years; range = 21-58 years), who were partial or nonresponders to SRI monotherapy or SRI combination therapy (antipsychotic, other antidepressant, or benzodiazepines), and had topiramate added over a minimum of 14 weeks, were reviewed. Baseline and endpoint Clinical Global Impression-Severity (CGI-S) and CGI-Improvement (CGI-I) were evaluated retrospectively. Eleven of 16 patients were responders (68.8%) with a CGI-I score of much improved or very much improved. The mean dose of topiramate was 253.1 +/- 93.9 mg/day. The mean time to response was 9.2 +/- 4.5 weeks. CGI-S scores decreased significantly from initiation of topiramate until 26 weeks, from 6.1 +/- 0.9 to 4.5 +/- 1.3 (P < .001). This case series suggests some preliminary evidence that the addition of topiramate may be useful in treatment-resistant OCD.

Pharmacotherapy of obsessive-compulsive disorder and obsessive-compulsive spectrum disorders

This article reviews new developments of pharmacotherapy in obsessive-compulsive disorder (OCD) and OC spectrum disorders of the past five years. New developments primarily involved the ex-tension of evidence of efficacy of serotonin reuptake inhibitors(SRIs), the use of atypical antipsychotics in addition to SRIs for treatment refractory patients, the combination of pharmacotherapy with behavior therapy, and studies assessing predictors of response. Today, frontline pharmacological treatment of OCD still consists of drugs with potent serotonin reuptake inhibition proper-ties. In case of non-response, treatment options comprise adding another drug, increasing the dose, switching drugs, or changing the mode of delivery.

Glutamate-modulating drugs as novel pharmacotherapeutic agents in the treatment of obsessive-compulsive disorder

SUMMARY

Obsessive-compulsive disorder (OCD) is a common psychiatric disorder that produces significant morbidity. The introduction of serotonin reuptake inhibitors in the 1980s represented an important advance in the treatment of OCD. However, few patients show complete remission of their symptoms, and some patients show minimal improvement with existing treatments. We review current treatment strategies and initial data supporting the efficacy of glutamate modulating agents as a novel class of pharmaceuticals for the treatment of OCD. Functional neuroimaging studies repeatedly reported metabolic hyperactivity in the cortico-striato-thalamo-cortical circuitry in patients with OCD. Recent magnetic resonance spectroscopy studies provide evidence of elevated glutamate levels in several brain regions in patients suffering from OCD. These findings raised the possibility that agents that reduce glutamate hyperactivity or its consequences in the CNS might be efficacious as novel therapeutic interventions. Indeed, initial evidence from our group suggests that the antiglutamatergic agent riluzole (Rilutek), which was developed for the treatment of amyotrophic lateral sclerosis, is effective in treatment-resistant OCD. Case reports suggest that other agents that modulate glutamatergic activity may likewise be effective. This new application of glutamate modulating agents holds promise for the treatment of this disabling and often inadequately treated disease.

Anticonvulsants in anxiety disorders

Anticonvulsant drugs have shown promising results in the treatment of mood disorders, leading to the investigation of their potential efficacy in other psychiatric disorders. Numerous case reports, open-label trials, and placebo- controlled trials investigating the use of anticonvulsants in the treatment of anxiety disorders have yielded broad and varying results. Generally, these studies have indicated a potential role for anticonvulsants in the treatment of anxiety as monotherapy or augmentation therapy; however, these early findings must be supported by additional investigation in large-scale, placebo-controlled studies. This article reviews past and current research being done in this novel area of psychopharmacology.

Pharmacological augmentation strategies for treatment-resistant obsessive-compulsive disorder

First-line treatment for obsessive-compulsive disorder (OCD) has been well-established for over a decade, although newer medications, such as citalopram and venlafaxine, have emerged to take a place among the older, more established serotonin re-uptake inhibitors (SRIs). Unfortunately, as many as 50% of all patients with OCD will have symptoms refractory to a single medication treatment trial, and a smaller percentage will remain refractory after two or more trials. The optimal dosage and duration for first-line trials have been established. Many strategies exist for patients who do not respond to first- or second-line medication trials, including behavioural therapy, switching to newer SRIs, and augmentation with additional medications. This review will focus on medication strategies for augmenting SRI treatment response in OCD treatment, including neuroleptic and serotonergic agents. Future investigations should include more controlled studies and investigate medications that are less likely to trigger extrapyramidal symptoms, diabetes mellitus and weight gain.

Antiepileptic Drugs in the Treatment of Anxiety Disorders

Pharmacotherapy for anxiety disorders is an active area of research. A variety of drug groups have been shown to be effective in treating many of the anxiety disorders, with selective serotonin reuptake inhibitors (SSRIs) being considered first-line agents for virtually all anxiety disorders. There is a clinical need for alternative drug treatments, as many patients do not achieve a complete response and experience significant adverse effects. The successful use of antiepileptic drugs in mood disorders has led clinicians and researchers to investigate their potential efficacy in other psychiatric disorders, particularly in anxiety disorders. There have been a number of investigations conducted in the form of case reports, case series and open-label trials, suggesting the potential usefulness of antiepileptic drug treatment in a variety of anxiety disorders. More reliable evidence for the use of antiepileptic drugs in anxiety disorders can be gleaned from recent placebo-controlled trials. Thus far, the strongest placebo-controlled evidence has demonstrated the efficacy of pregabalin in treating social phobia and generalised anxiety disorder, while smaller or less robust controlled trials have suggested the potential efficacy of gabapentin in social phobia, lamotrigine in post-traumatic stress disorder, and valproic acid in panic disorder. Antiepileptic drugs may have a place in the treatment of anxiety disorders; however, further investigation is warranted to determine in what circumstances they should be used as monotherapy or as augmenting agents in individuals who are partially or non-responsive to conventional therapy.

Current and potential pharmacological treatments for obsessive-compulsive disorder

In the past 20 years, several effective treatments have been developed for obsessive-compulsive disorder. Despite this, it is a disorder that is often inadequately treated by available therapies. Recent advances in neuroimaging and neurophysiology have provided some clues to possible treatments that may be more effective in treating this disorder. Serotonin agents remain the cornerstone of pharmacological treatment for obsessive-compulsive disorder. The development of agents that target specific serotonin receptor subtypes may improve the effectiveness of drug treatment. Other possible future treatment approaches are also discussed.

A placebo-controlled, cross-over trial of lamotrigine in depersonalization disorder

There is evidence to support the view that glutamate hyperactivity might be relevant to the neurobiology of depersonalization. We tested the efficacy of lamotrigine, which reduces glutamate release, as a treatment for patients with depersonalization disorder. A double-blind, placebo-controlled, cross-over design was used to evaluate 12 weeks of treatment of lamotrigine. Subjects comprised nine patients with DSM-IV depersonalization disorder. Changes on the Cambridge Depersonalization Scale and the Present State Examination depersonalization/derealization items were compared across the two cross-over periods. Lamotrigine was not significantly superior to placebo. None of the nine patients was deemed a responder to the lamotrigine arm of the cross-over. Lamotrigine does not seem to be useful as a sole medication in the treatment of depersonalization disorder.