Inositol augmentation of serotonin reuptake inhibitors in treatment-refractory obsessive-compulsive disorder: an open trial

Neurobiology and Applications of Inositol in Psychiatry: A Narrative Review

Inositol is a natural sugar-like compound, commonly present in many plants and foods. It is involved in several biochemical pathways, most of them controlling vital cellular mechanisms, such as cell development, signaling and nuclear processes, metabolic and endocrine modulation, cell growth, signal transduction, etc. In this narrative review, we focused on the role of inositol in human brain physiology and pathology, with the aim of providing an update on both potential applications and current limits in its use in psychiatric disorders. Overall, imaging and biomolecular studies have shown the role of inositol levels in the pathogenesis of mood disorders. However, when administered as monotherapy or in addition to conventional drugs, inositol did not seem to influence clinical outcomes in both mood and psychotic disorders. Conversely, more encouraging results have emerged for the treatment of panic disorders. We concluded that, despite its multifaceted neurobiological activities and some positive findings, to date, data on the efficacy of inositol in the treatment of psychiatric disorders are still controversial, partly due to the heterogeneity of supporting studies. Therefore, systematic use of inositol in routine clinical practice cannot be recommended yet, although further basic and translational research should be encouraged.

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.

The Biomedical Uses of Inositols: A Nutraceutical Approach to Metabolic Dysfunction in Aging and Neurodegenerative Diseases

Inositols are sugar-like compounds that are widely distributed in nature and are a part of membrane molecules, participating as second messengers in several cell-signaling processes. Isolation and characterization of inositol phosphoglycans containing myo- or d-chiro-inositol have been milestones for understanding the physiological regulation of insulin signaling. Other functions of inositols have been derived from the existence of multiple stereoisomers, which may confer antioxidant properties. In the brain, fluctuation of inositols in extracellular and intracellular compartments regulates neuronal and glial activity. Myo-inositol imbalance is observed in psychiatric diseases and its use shows efficacy for treatment of depression, anxiety, and compulsive disorders. Epi- and scyllo-inositol isomers are capable of stabilizing non-toxic forms of β-amyloid proteins, which are characteristic of Alzheimer's disease and cognitive dementia in Down's syndrome, both associated with brain insulin resistance. However, uncertainties of the intrinsic mechanisms of inositols regarding their biology are still unsolved. This work presents a critical review of inositol actions on insulin signaling, oxidative stress, and endothelial dysfunction, and its potential for either preventing or delaying cognitive impairment in aging and neurodegenerative diseases. The biomedical uses of inositols may represent a paradigm in the industrial approach perspective, which has generated growing interest for two decades, accompanied by clinical trials for Alzheimer's disease.

Nutritional and herbal supplements in the treatment of obsessive compulsive disorder

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder that is characterised by obsessions and compulsions. The recommended treatments for OCD are cognitive– behavioural therapy using exposure and response prevention and/or pharmacotherapy. On the other hand, some nutritional and herbal supplements may be effective in the treatment of OCD. Nutritional and herbal supplements in OCD treatment will be reviewed in this paper. PubMed (Medline), Cochrane Library and Google Scholar databases were reviewed for the topic. There are some supplements that have been researched in OCD treatment studies such as vitamin D, vitamin B₁₂, folic acid, homocysteine, trace elements, N-acetyl cysteine, glycine, myoinositol, St John’s wort, milk thistle, valerian root, curcumin and borage. The effectiveness of herbal and nutritional supplements in the treatment of OCD should be supported with more conclusive evidence.

Drug Treatment of Trichotillomania (Hair-Pulling Disorder), Excoriation (Skin-picking) Disorder, and Nail-biting (Onychophagia)

BACKGROUND

Trichotillomania (TTM), excoriation (or skin-picking) disorder and some severe forms of onychophagia are classified under obsessive-compulsive and related disorders. There are different interacting neurotransmitter systems involved in the pathophysiology of impulse-control disorders, implicating noradrenaline, serotonin, dopamine, opioid peptides and glutamate, hence investigators focused on drugs able to act on these transmitters. Our aim was to critically review the efficacy of the drugs employed in impulse-control disorders.

METHODS

We searched for controlled drug trials to treat TTM, excoriation, and/or nail-biting six databases (PubMed, Cochrane, Scopus, CINAHL, PsycINFO/PsycARTICLES, and Web of Science), using the search strategy: (trichotillomania OR "excoriation disorder" OR "face picking" OR "skin picking" OR "hair pulling" OR onychophagia OR "nail-biting") AND drug treatment on 12 March 2018 for all databases. We followed in our method of identifying relevant literature the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

RESULTS

SSRIs and clomipramine are considered first-line in TTM. In addition, family members of TTM patients are often affected by obsessive-compulsive spectrum disorders. Other drugs used in the treatment of TTM are lamotrigine, olanzapine, N-Acetylcysteine, inositol, and naltrexone.

CONCLUSION

The treatment of TTM, excoriation disorder and nail-biting is still rather disappointing. Conjectures made from preclinical studies and the relative pathophysiological hypotheses found poor confirmations at a clinical level. There is a need for further studies and the integration of pharmacological and psychotherapeutic. Our results point to the need of integrating personalised medicine principles in the treatment of these patients.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

Integrated analysis of the genetic basis of suicidal behavior: what has been shown by structural genetic studies so far

OBJECTIVE

In recent decades, the role of genetic factors in the predisposition to suicidal behavior has attracted considerable attention. Although each genetic investigation appears to be valuable, no one study on its own can comprehensively explain the etiology of suicidal behavior.

METHODS

In this study, using a broad literature review, we found the suicide-associated gene coexpression network. In addition, cytoband, molecular function, biological process, cellular component, tissue-based expression, and disease/disorder enrichment analyses were carried out to determine the most central cellular and molecular infrastructures involved in suicidal behavior.

RESULTS

The reconstructed network consisted of 104 genes, including 91 previously known genes and 13 novel genes, and 354 interactions. Topological analysis showed that in total, CCK, INPP1, DDC, and NPY genes are the most fundamental hubs in the network. We found that suicide genes are significantly concentrated within chromosomes 11 and 6. Further analysis showed that monoaminergic signal transduction, especially through GPCRs, in the cingulate gyrus, superior prefrontal gyrus, dorsal striatum, and the cerebellum are the main, deficient routes in suicide. Moreover, it turned out that genetically, suicidal behavior is more likely in patients with mood and affective disorders.

CONCLUSION

Like other behavioral disorders, suicide has a complex and multifactorial basis and at present, the only approaches to the integrated study of such disorders are computer-based methods. The results of such studies, although subject to a degree of uncertainty, however, can pave the way for future basic and clinical studies.

A double-blind, placebo-controlled study of inositol in trichotillomania

Trichotillomania is characterized by repetitive pulling that causes noticeable hair loss. Data on the pharmacological treatment of trichotillomania are limited, with no clear first-line agent. The aim of the current study was to determine the efficacy and tolerability of inositol in adults with trichotillomania. A total of 38 individuals (35 women; mean age: 28.9±11.4) with trichotillomania entered a 10-week, double-blind, placebo-controlled trial to evaluate the safety and efficacy of inositol (dosing ranging from 6 to 18 g/day). Patients were assessed using the Massachusetts General Hospital Hair Pulling Scale, the NIMH Trichotillomania Severity Scale, Clinical Global Impression Scale, and measures of depression, anxiety, and psychosocial functioning. Outcomes were examined using a linear mixed-effects model. Patients assigned to inositol failed to show significantly greater reductions on primary or secondary outcomes measures compared with placebo (all P>0.05). At study endpoint, 42.1% of patients were 'much or very much improved' on inositol compared with 35.3% on placebo. This is the first study assessing the efficacy of inositol in the treatment of trichotillomania, but found no differences in symptom reductions between inositol and placebo. Future studies should examine whether inositol may be beneficial in controlling pulling behavior in a subgroup of individuals with trichotillomania.

Complementary and alternative therapies as add-on to pharmacotherapy for mood and anxiety disorders: a systematic review

BACKGROUND

Depressed and anxious patients often combine complementary and alternative medicine (CAM) therapies with conventional pharmacotherapy to self-treat symptoms. The benefits and risks of such combination strategies have not been fully evaluated. This paper evaluates the risk-benefit profile of CAM augmentation to antidepressants in affective conditions.

METHODS

PubMed was searched for all available clinical reports published in English up to December 2012. Data were evaluated based on graded levels of evidence for efficacy and safety.

RESULTS

Generally, the evidence base is significantly larger for depression than for anxiety disorder. In unipolar depression, there is Level 2 evidence for adjunctive sleep deprivation (SD) and Free and Easy Wanderer Plus (FEWP), and Level 3 for exercise, yoga, light therapy (LT), omega-3 fatty acids, S-adenosylmethionine and tryptophan. In bipolar depression, there is Level 1 evidence for adjunctive omega-3s, Level 2 for SD, and Level 3 for LT and FEWP. In anxiety conditions, exercise augmentation has Level 3 support in generalized anxiety disorder and panic disorder. Though mostly well-tolerated, these therapies can only be recommended as third-line interventions due to the quality of available evidence.

LIMITATIONS

Overall, the literature is limited. Studies often had methodological weaknesses, with little information on long-term use and on potential drug-CAM interactions. Many CAM studies were not published in English.

CONCLUSIONS

While several CAM therapies show some evidence of benefit as augmentation in depressive disorders, such evidence is largely lacking in anxiety disorders. The general dearth of adequate safety and tolerability data encourages caution in clinical use.

Complementary medicine, self-help, and lifestyle interventions for obsessive compulsive disorder (OCD) and the OCD spectrum: a systematic review

BACKGROUND

In Obsessive Compulsive Disorder (OCD) current standard pharmacotherapies may be of limited efficacy. Non-conventional interventions such as Complementary and Alternative Medicine (CAM), self-help techniques, and lifestyle interventions are commonly used by sufferers of OCD, however to date no systematic review of this specific area exists.

METHODS

We conducted a systematic review of studies using CAM, self-help, and lifestyle interventions for treatment of OCD and trichotillomania (TTM). PubMed, PsycINFO, China Academic Journals Full-text Database, The Cochrane Library and CINAHL were searched (up to Jan 11th 2011), for controlled clinical trials using non-conventional interventions for OCD. A quality analysis using a purpose-designed scale and an estimation of effect sizes (Cohen's d) where data was available, were also calculated.

RESULTS

The literature search revealed 14 studies that met inclusion criteria. Methodological quality of nutraceutical studies (nutrients and herbal medicines) were rated as high (mean 8.6/10), whereas mind-body or self-help studies were poorer (mean 6.1/10). In OCD, tentative evidentiary support from methodologically weak studies was found for mindfulness meditation (d=0.63), electroacupuncture (d=1.16), and kundalini yoga (d=1.61). Better designed studies using the nutrient glycine (d=1.10), and traditional herbal medicines milk thistle (insufficient data for calculating d) and borage (d=1.67) also revealed positive results. A rigorous study showed that N-acetylcysteine (d=1.31) was effective in TTM, while self-help technique "movement decoupling" also demonstrated efficacy (d=0.94). Mixed evidence was found for myo-inositol (mean d=0.98). Controlled studies suggest that St John's wort, EPA, and meridian-tapping are ineffective in treating OCD.

CONCLUSIONS

While several studies were positive, these were un-replicated and commonly used small samples. This precludes firm confidence in the strength of clinical effect. Preliminary evidence however is encouraging, and more rigorous research of some of the more hypothesis-based interventions in the treatment of OCD and TTM may be indicated.

Nutraceuticals in the treatment of obsessive compulsive disorder (OCD): a review of mechanistic and clinical evidence

Obsessive-compulsive disorder (OCD) is a debilitating mental illness which has a significant impact on quality of life. First-line SSRI treatments for OCD typically are of limited benefit to only 40-60% of patients, and are associated with a range of adverse side effects. Current preclinical research investigating nutraceuticals (natural products) for OCD, reveals encouraging novel activity in modulating key pathways suggested to be involved in the pathogenesis of OCD (glutamatergic and serotonergic pathway dysregulation). Emerging clinical evidence also appears to tentatively support certain nutrients and plant-based interventions with known active constituents which modulate these pathways: N-acetlycysteine, myo-inositol, glycine, and milk thistle (Silybum marianum). The serotonin precursor tryptophan is unlikely to be of use in treating OCD while 5-HTP may possibly be a more effective precursor strategy. However, there is currently no clinical evidence to test the efficacy of either of these substances. Currently the balance of clinical evidence does not support the use of St. John's wort (Hypericum perforatum) in OCD. While clinical research in this area is in its infancy, further research into nutraceuticals is warranted in light of the promising preclinical data regarding their mechanisms of action and their favourable side effect profiles in comparison to current SSRI treatments. It is recommended that future clinical trials of nutraceutical treatments for OCD utilize randomized placebo-controlled study designs and considerably larger sample sizes in order to properly test for efficacy.

Drug treatment of obsessive-compulsive disorder

Knowledge of pharmacotherapeutic treatment options in obsessive-compulsive disorder (OCD) has grown considerably over the past 40 years. Serotonergic antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) and clomipramine, are the established pharmacologic first-line treatment of OCD. Medium to large dosages and acute treatment for at least 3 months are recommended until efficacy is assessed. In case of significant improvement, maintenance treatment is necessary. Unfortunately, about half of the patients do not respond sufficiently to oral serotonergic antidepressants; augmentation with atypical antipsychotics is an established second-line drug treatment strategy. Alternatives include intravenous serotonergic antidepressants and combination with or switch to cognitive behavioral psychotherapy. Remarkably, a considerable proportion of OCD patients still do not receive rational drug treatment. Novel research approaches, such as preliminary treatment studies with glutamatergic substances, and trials with further drugs, as well as needed aspects of future research, are reviewed.

Current trends in drug treatment of obsessive-compulsive disorder

This article aims to highlight current trends in the pharmacologic management of obsessive-compulsive disorder (OCD). A systematic search of the electronic database MEDLINE was conducted. The first case report of clomipramine efficacy in the management OCD more than 40 years ago gave new hope for the treatment of this debilitating disorder. Selective serotonin reuptake inhibitors (SSRIs) proved to have a similar efficacy profile compared with clomipramine but had a superior tolerability profile. While many patients with OCD respond to SSRIs or clomipramine, the treatment of those with refractory OCD remains challenging. Different augmentation agents in treatment-resistant OCD have been explored, with antipsychotic agents having the largest supporting evidence base. Nevertheless, new pharmacologic treatment options are required and are under investigation.

Quetiapine versus clomipramine in the augmentation of selective serotonin reuptake inhibitors for the treatment of obsessive-compulsive disorder: a randomized, open-label trial

After 12 weeks of selective serotonin reuptake inhibitor (SSRI) monotherapy with inadequate response, 10 patients received clomipramine and 11 received quetiapine as augmentation agents of the SSRI. The primary outcome measure was the difference between initial and final scores of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), rated in a blinded fashion, and the score of clinical global improvement (CGI-I). Statistical analyses were performed using nonparametric tests to evaluate treatment efficacy and the difference between treatment groups. Percentile plots were constructed with YBOCS scores from the clomipramine and quetiapine groups. Considering response a >or=35% reduction in the initial Y-BOCS score plus a rating of 'much improved' or 'very much improved' on CGI-I, four of eleven quetiapine patients and one out of ten clomipramine patients were classified as responders. The mean final Y-BOCS score was significantly lower than baseline in the quetiapine augmentation group (P = 0.023), but not in the clomipramine augmentation group (P = 0.503). The difference between groups showed a trend towards significance only at week 4, the mean Y-BOCS score being lower for those receiving quetiapine (P = 0.052). A difference between groups was also observed at week 4 according to percentile plots. These results corroborate previous findings of quetiapine augmentation efficacy in obsessive-compulsive disorder (OCD). Clomipramine augmentation did not produce a significant reduction in Y-BOCS scores. Higher target maximum dosages might have yielded different results.

High-dose glycine treatment of refractory obsessive-compulsive disorder and body dysmorphic disorder in a 5-year period

This paper describes an individual who was diagnosed with obsessive-compulsive disorder (OCD) and body dysmorphic disorder (BDD) at age 17 when education was discontinued. By age 19, he was housebound without social contacts except for parents. Adequate trials of three selective serotonin reuptake inhibitors, two with atypical neuroleptics, were ineffective. Major exacerbations following ear infections involving Group A β-hemolytic streptococcus at ages 19 and 20 led to intravenous immune globulin therapy, which was also ineffective. At age 22, another severe exacerbation followed antibiotic treatment for H. pylori. This led to a hypothesis that postulates deficient signal transduction by the N-methyl-D-aspartate receptor (NMDAR). Treatment with glycine, an NMDAR coagonist, over 5 years led to robust reduction of OCD/BDD signs and symptoms except for partial relapses during treatment cessation. Education and social life were resumed and evidence suggests improved cognition. Our findings motivate further study of glycine treatment of OCD and BDD.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for the pharmacological treatment of anxiety, obsessive-compulsive and post-traumatic stress disorders - first revision

In this report, which is an update of a guideline published in 2002 (Bandelow et al. 2002, World J Biol Psychiatry 3:171), recommendations for the pharmacological treatment of anxiety disorder, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD) are presented. Since the publication of the first version of this guideline, a substantial number of new randomized controlled studies of anxiolytics have been published. In particular, more relapse prevention studies are now available that show sustained efficacy of anxiolytic drugs. The recommendations, developed by the World Federation of Societies of Biological Psychiatry (WFSBP) Task Force for the Pharmacological Treatment of Anxiety, Obsessive-Compulsive and Post-traumatic Stress Disorders, a consensus panel of 30 international experts, are now based on 510 published randomized, placebo- or comparator-controlled clinical studies (RCTs) and 130 open studies and case reports. First-line treatments for these disorders are selective serotonin reuptake inhibitors (SSRIs), serotonin-noradrenaline reuptake inhibitors (SNRIs) and the calcium channel modulator pregabalin. Tricyclic antidepressants (TCAs) are equally effective for some disorders, but many are less well tolerated than the SSRIs/SNRIs. In treatment-resistant cases, benzodiazepines may be used when the patient does not have a history of substance abuse disorders. Potential treatment options for patients unresponsive to standard treatments are described in this overview. Although these guidelines focus on medications, non-pharmacological were also considered. Cognitive behavioural therapy (CBT) and other variants of behaviour therapy have been sufficiently investigated in controlled studies in patients with anxiety disorders, OCD, and PTSD to support them being recommended either alone or in combination with the above medicines.

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.

A review of the possible relevance of inositol and the phosphatidylinositol second messenger system (PI-cycle) to psychiatric disorders--focus on magnetic resonance spectroscopy (MRS) studies

Myo-inositol is an important part of the phosphatidylinositol second messenger system (PI-cycle). Abnormalities in nerve cell myo-inositol levels and/or PI-cycle regulation has been suggested as being involved in the pathophysiology and/or treatment of many psychiatric disorders including bipolar disorder, major depressive disorder, panic disorder, obsessive-compulsive disorder, eating disorders and schizophrenia. This review examines the metabolism and biochemical importance of myo-inositol and the PI-cycle. It relates this to the current in vivo evidence for myo-inositol and PI-cycle involvement in these psychiatric disorders, particularly focusing upon the magnetic resonance spectroscopy (MRS) findings in patient studies to date. From this review it is concluded that while the evidence suggests probable relevance to the pathophysiology and/or treatment of bipolar disorder, there is much less support for a significant role for the PI-cycle or myo-inositol in any other psychiatric disorder. More definitive investigation is required before PI-cycle dysfunction can be considered specific to bipolar disorder.

Obsessive-compulsive disorder: a critical review of therapeutic perspectives

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a chronic disabling disease with profound implications for social functioning. Thirty per cent of all patients with OCD show insufficient improvement with state-of-the-art treatment. Conventional treatment and alternative treatment options for this population were investigated.

METHOD

A selective review of the relevant scientific literature on OCD treatment and treatment resistance was conducted.

RESULTS

In addition to serotonin reuptake inhibitors (SRIs) and cognitive-behavioural therapy, alternative monotherapies, SRI augmentation strategies with a variety of drugs and electroconvulsive therapy have shown results in individual cases, but no conclusive evidence has been found in placebo-controlled trials. While studies investigating neurosurgery for refractory OCD show positive results, most of these studies have methodological shortcomings.

CONCLUSION

Novel approaches currently under investigation that have shown promising effects for treatment-resistant OCD include SRI augmentation with atypical antipsychotics and chronic deep brain stimulation, a new surgical technique. Placebo-controlled trials for both treatment options will be needed to confirm preliminary findings.

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.

Single photon emission computed tomography (SPECT) in obsessive-compulsive disorder before and after treatment with inositol

Inositol, a glucose isomer and second messenger precursor, regulates numerous cellular functions and has demonstrated efficacy in obsessive-compulsive disorder (OCD) through mechanisms that remain unclear. The effect of inositol treatment on brain function in OCD has not been studied to date. Fourteen OCD subjects underwent single photon emission computed tomography (SPECT) with Tc-99m HMPAO before and after 12 weeks of treatment with inositol. Whole brain voxel-wise SPM was used to assess differences in perfusion between responders and nonresponders before and after treatment as well as the effect of treatment for the group as a whole. There was 1) deactivation in OCD responders relative to nonresponders following treatment with inositol in the left superior temporal gyrus, middle frontal gyrus and precuneus, and the right paramedian post-central gyrus; 2) no significant regions of deactivation for the group as a whole posttreatment; and 3) a single cluster of higher perfusion in the left medial prefrontal region in responders compared to nonresponders at baseline. Significant reductions in the YBOCS and CGI-severity scores followed treatment. These data are only partly consistent with previous functional imaging work on OCD. They may support the idea that inositol effects a clinical response through alternate neuronal circuitry to the SSRIs and may complement animal work proposing an overlapping but distinct mechanism of action.

Defining the neuromolecular action of myo-inositol: application to obsessive-compulsive disorder

Dietary inositol is incorporated into neuronal cell membranes as inositol phospholipids where it serves as a key metabolic precursor in G protein-coupled receptors. In the brain, several subtypes of adrenergic, cholinergic, serotonergic and metabotropic glutamatergic receptors are coupled to the hydrolysis of phosphoinositides (PI) with myo-inositol (MI) crucial to the resynthesis of PI and the maintenance and effectiveness of signalling. Despite a mode of action that remains illusive, MI has demonstrated therapeutic efficacy in obsessive-compulsive disorder (OCD), putative OCD-spectrum disorders, as well as panic and depression. Behavioural and biochemical studies indicate that this efficacy does not involve simply the replenishing of the membrane PI pool. In addition to its precursory role in cell signalling, inositol lipids alter receptor sensitivity, can direct membrane trafficking events, and have been found to modulate an increasing array of signalling proteins. These effects may afford MI an ability to modulate the interaction between neurotransmitters, drugs, receptors and signalling proteins. This paper reviews the neuromolecular and genetic aspects of OCD in terms of the PI-linked 5HT receptor subtypes and relates these to the behavioural and therapeutic effects of MI. Since OCD often is poorly responsive to current drug treatment, understanding the neuropharmacology of MI holds great promise for understanding the neuropathology of this and other MI-responsive disorders.

Pharmacotherapy for obsessive-compulsive disorder

SSRIs and the tricyclic antidepressant clomipramine are the first-line therapies for patients with OCD, with the side-effect profile of SSRIs being more favorable than that of clomipramine. As many as 40% to 60% of patients with OCD may not respond to adequate trials of SRIs. Not all patients tolerate SSRIs, and delays in full therapeutic responses often occur. Thus, other pharmacologic approaches to treating patients with OCD have been investigated. Augmentation and monotherapy have been explored with serotonergic enhancers, dopamine and 5-HT antagonists, enhancers of second-messenger systems, and GABAergic agents with varying efficacy.

Therapeutic approaches to the treatment of refractory obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a debilitating condition that afflicts approximately 1% to 3% of the world population. The primary treatments are selective serotonin reuptake inhibitors and behavioral therapy. Despite therapy, approximately 30% to 40% of patients continue to suffer from disabling OCD symptoms. This article addresses the range of treatment options for patients with refractory OCD, focusing upon novel strategies and the most recent research.

Biological therapies for obsessive-compulsive disorder

Two treatments have demonstrated efficacy in OCD, exposure and response (ritual) prevention (EX/RP) and pharmacotherapy with serotonin reuptake inhibitors (SRIs). In this article, which is the third in a three-part series, the authors present an overview of the role of biological treatments for OCD. The evidence for the efficacy of the serotonin reuptake inhibitors (clomipramine and the five selective serotonin reuptake inhibitors "SSRIs" fluvoxamine, fluoxetine, paroxetine, sertraline, and citalopram) as monotherapy for OCD is reviewed. The authors also discuss the rationale for choosing among these agents for specific patients. Research on other types of medication monotherapies for OCD is also discussed. The authors then cover strategies for treatment-resistant OCD, including combining EX/RP and SRI medication treatment, combining clomipramine and an SSRI, use of augmenting medications, and use of intravenous clomipramine. Findings concerning the use of other somatic therapies for treatment-resistant OCD, including electroconvulsive therapy, neurosurgery, plasma exchange/IV immunoglobulin/maintenance antibiotics, and transcranial magnetic stimulation, are also reviewed. Finally, the authors discuss what is known about matching treatments to patients with certain specific symptom clusters, how long to continue maintenance medication treatment, and how to terminate treatment.