Meta-analysis of association between obsessive-compulsive disorder and the 3' region of neuronal glutamate transporter gene SLC1A1.

The neuronal glutamate transporter gene SLC1A1 is a candidate gene for obsessive-compulsive disorder (OCD) based on linkage studies and convergent evidence implicating glutamate in OCD etiology. The 3' end of SLC1A1 is the only genomic region with consistently demonstrated OCD association, especially when analyzing male-only probands. However, specific allele associations have not been consistently replicated, and recent OCD genome-wide association and meta-analysis studies have not incorporated all previously associated SLC1A1 SNPs. To clarify the nature of association between SLC1A1 and OCD, pooled analysis was performed on all available relevant raw study data, comprising a final sample of 815 trios, 306 cases and 634 controls. This revealed weak association between OCD and one of nine tested SLC1A1 polymorphisms (rs301443; uncorrected P = 0.046; non-significant corrected P). Secondary analyses of male-affecteds only (N = 358 trios and 133 cases) demonstrated modest association between OCD and a different SNP (rs12682807; uncorrected P = 0.012; non-significant corrected P). Findings of this meta-analysis are consistent with the trend of previous candidate gene studies in psychiatry and do not clarify the putative role of SLC1A1 in OCD pathophysiology. Nonetheless, it may be important to further examine the potential associations demonstrated in this amalgamated sample, especially since the SNPs with modest associations were not included in the more highly powered recent GWAS or in a past meta-analysis including five SLC1A1 polymorphisms. This study underscores the need for much larger sample sizes in future genetic association studies and suggests that next-generation sequencing may be beneficial in examining the potential role of rare variants in OCD.

Effect of axis II diagnoses on treatment outcome with clomipramine in 55 patients with obsessive-compulsive disorder.

We used the Structured Interview for DSM-III Personality Disorders to diagnose DSM-III personality disorders systematically in 55 patients with obsessive-compulsive disorder in the active-treatment cell of a controlled trial of clomipramine hydrochloride. Patients with a cluster A personality disorder had significantly higher obsessive-compulsive disorder severity scores at baseline, and the number of personality disorders was strongly related to baseline severity of obsessive-compulsive disorder symptoms. At the conclusion of the 12-week study, we found no significant difference in treatment outcome with clomipramine between those patients with at least one personality disorder and those with no personality disorders. However, the presence of schizotypal, borderline, and avoidant personality disorders, along with total number of personality disorders, did predict poorer treatment outcome. These variables were strongly related to having at least one cluster A personality disorder diagnosis, which was also a strong predictor of poorer outcome. Implications of these findings are discussed.

Cingulotomy for refractory obsessive-compulsive disorder. A long-term follow-up of 33 patients.

To evaluate the feasibility of cingulotomy as a treatment for patients with intractable obsessive-compulsive disorder, we evaluated the records of all 35 patients with this diagnosis who had undergone one or more such procedures at Massachusetts General Hospital, Boston, during the last 25 years. Retrospectively, all but two of these patients met DSM-III-R criteria for obsessive-compulsive disorder. Six patients were deceased; four by suicide. Questionnaires were sent to the remaining 27 patients with obsessive-compulsive disorder; 17 patients returned the questionnaire and another agreed to an interview without completing the forms. Sixteen of these 18 patients participated in a telephone interview, and patient reports were corroborated by an informant in 10 cases. Despite the presence of some side effects, such as easily controlled seizures (9%) and transient mania (6%), the results of this investigation support the use of cingulotomy as a potentially effective treatment for patients with severe and disabling obsessive-compulsive disorder. With the use of very conservative criteria, we estimated that at least 25% to 30% of the patients benefited substantially from this procedure. Similar results were found in a preliminary prospective study of four patients who recently underwent cingulotomy after state-of-the-art preoperative treatments had failed.

Regional cerebral blood flow measured during symptom provocation in obsessive-compulsive disorder using oxygen 15-labeled carbon dioxide and positron emission tomography.

BACKGROUND: The study was designed to determine the mediating neuroanatomy of obsessive-compulsive disorder (OCD). METHODS: The short half-life tracer oxygen 15-labeled carbon dioxide was used to allow for repeated positron emission tomographic determinations of regional cerebral blood flow on each of eight patients with OCD during a resting and a provoked (symptomatic) state. RESULTS: Individually tailored provocative stimuli were successful in provoking OCD symptoms, in comparison with paired innocuous stimuli, as measured by self-report on OCD analogue scales (P = .002). Omnibus subtraction images demonstrated a statistically significant increase in relative regional cerebral blood flow during the OCD symptomatic state vs the resting state in right caudate nucleus (P < .006), left anterior cingulate cortex (P < .045), and bilateral orbitofrontal cortex (P < .008); increases in the left thalamus approached but did not reach statistical significance (P = .07). CONCLUSIONS: These findings are consistent with results of previous functional neuroimaging studies and contemporary neurocircuitry models of OCD. The data further implicate orbitofrontal cortex, caudate nucleus, and anterior cingulate cortex in the pathophysiology of OCD and in mediating OCD symptoms.

Cingulotomy for intractable obsessive-compulsive disorder. Prospective long-term follow-up of 18 patients.

BACKGROUND: The purpose of this study was to assess prospectively long-term change in obsessive-compulsive disorder (OCD) symptoms in patients with an OCD diagnosis that was confirmed by structured interview and with documented unsuccessful trials of multiple medications and attempts at behavior therapy. METHODS: We conducted an unblinded preoperative and follow-up assessment of comorbid diagnosis; OCD, depressive, and anxiety symptoms; and functional status in 18 patients who underwent cingulotomy. RESULTS: At a mean follow-up of 26.8 months, five patients (28%) met conservative criteria for treatment responders, and three others (17%) were partial responders. The group improved significantly in mean functional status, and few serious adverse events were found. Improvement in OCD symptoms was strongly correlated with improvement in depressive and anxiety symptoms. CONCLUSIONS: The rate of clinical improvement was consistent with a previous retrospective study in the same setting, indicating that 25% to 30% of the patients who previously were unresponsive to medication and behavioral treatments are significantly improved after cingulotomy. Cingulotomy remains a last resort treatment for severely incapacitated patients who have not responded to all other state-of-the-art pharmacological and behavioral treatments for OCD and is not to be taken lightly.

Standardized assessment of personality disorders in obsessive-compulsive disorder.

We assessed 96 patients with obsessive-compulsive disorder for DSM-III personality disorder diagnoses with a standardized interview instrument (Structured Interview for the DSM-III Personality Disorders). Fifty patients (52%) met criteria for at least one personality disorder, with mixed, dependent, and histrionic personality disorders most frequently diagnosed. Compulsive personality disorder was diagnosed in only 6 patients (6%), 5 of whom had had onset of obsessive-compulsive symptoms before the age of 10 years, indicating that DSM-III compulsive personality disorder is not invariably a premorbid condition for the development of obsessive-compulsive disorder. Schizotypal personality disorder, at 5%, was found to be less common than in past samples, reflecting differences in either assessment methods or sampling.

A positron emission tomographic study of simple phobic symptom provocation.

BACKGROUND: The goal of this study was to determine the mediating neuroanatomy of simple phobic symptoms. METHODS: Positron emission tomography and oxygen 15 were used to measure normalized regional cerebral blood flow in seven subjects with simple phobia during control and provoked states. Stereotactic transformation and statistical parametric mapping techniques were employed to determine the locations of significant activation. RESULTS: Statistical parametric maps demonstrated significant increases in normalized regional blood flow for the symptomatic state compared with the control state in the anterior cingulate cortex, the insular cortex, the anterior temporal cortex, the somatosensory cortex, the posterior medial orbitofrontal cortex, and the thalamus. CONCLUSIONS: The results suggest that anxiety associated with the simple phobic symptomatic state is mediated by paralimbic structures. Moreover, activation of somatosensory cortex may reflect tactile imagery as one component of the phobic symptomatic condition.

A multicenter investigation of fixed-dose fluoxetine in the treatment of obsessive-compulsive disorder.

OBJECTIVES: To determine the effectiveness of fluoxetine hydrochloride at fixed doses of 20 mg/d, 40 mg/d, and 60 mg/d in patients with obsessive-compulsive disorder (OCD) and to evaluate its safety. METHODS: Fixed-dose fluoxetine hydrochloride (20 mg/d, 40 mg/d, 60 mg/d) was compared with placebo in two randomized, double-blind, parallel, 13-week trials of identical design in 355 outpatients with OCD aged 15 to 70 years (DSM-III-R criteria; 1 year's duration or longer; depression secondary if present). RESULTS: Fluoxetine (all doses) was significantly (P < or = .001) superior to placebo on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) total score (mean baseline-to-end-point decrease, 4.6, 5.5, and 6.5 vs 0.9, respectively, studies pooled) and other efficacy measures (P < or = .01). A trend suggesting greater efficacy at 60 mg/d was observed. Most patients (79.2%) completed the study. Eight adverse events were statistically significantly more frequent with fluoxetine and one, with placebo. For some events, incidence tended to increase with increasing dosage; however, few patients discontinued treatment for any single event. CONCLUSION: Fluoxetine was associated with a statistically significant reduction in OCD severity, including time engaged in obsessional and/or compulsive behaviors. Adverse events infrequently led to study discontinuation.

A symptom provocation study of posttraumatic stress disorder using positron emission tomography and script-driven imagery.

BACKGROUND: Previous studies have used symptom provocation and positron emission tomography to delineate the brain systems that mediate various anxiety states. Using an analogous approach, the goal of this study was to measure regional cerebral blood flow changes associated with posttraumatic stress disorder (PTSD) symptoms. METHODS: Eight patients with PTSD, screened as physiologically responsive to a script-driven imagery symptom provocation paradigm, were exposed sequentially to audiotaped traumatic and neutral scripts in conjunction with positron emission tomography. Heart rate and subjective measures of emotional state were obtained for each condition. Statistical mapping techniques were used to determine locations of significant brain activation. RESULTS: Increases in normalized blood flow were found for the traumatic as compared with control conditions in right-sided limbic, paralimbic, and visual areas; decreases were found in left inferior frontal and middle temporal cortex. CONCLUSIONS: The results suggest that emotions associated with the PTSD symptomatic state are mediated by the limbic and paralimbic systems within the right hemisphere. Activation of visual cortex may correspond to the visual component of PTSD reexperiencing phenomena.

Cerebral structural abnormalities in obsessive-compulsive disorder. A quantitative morphometric magnetic resonance imaging study.

BACKGROUND: A previous pilot study of only posterior brain regions found lower white-matter volume in patients with obsessive-compulsive disorder than in normal control subjects. We used new cohorts of patients and matched normal control subjects to study whole-brain volume differences between these groups with magnetic resonance imaging-based morphometry. METHODS: Ten female patients with obsessive-compulsive disorder and 10 female control subjects, matched for handedness, age, weight, education, and verbal IQ, underwent magnetic resonance imaging with a 3-dimensional volumetric protocol. Scans were blindly normalized and segmented by means of well-characterized semiautomated intensity contour mapping and differential intensity contour algorithms. Brain structures investigated included the cerebral hemispheres, cerebral cortex, diencephalon, caudate, putamen, globus pallidus, hippocampus amygdala, third and fourth ventricles, corpus callosum, operculum, cerebellum, and brain stem. Anterior to posterior neocortical regions, including precallosum, anterior pericallosum, posterior pericallosum, and retrocallosum, with adjacent white matter were also measured. Volumes found different between groups were correlated with Yale-Brown Obsessive Compulsive Scale score and Rey-Osterieth Complex Figure Test measures. RESULTS: Confirming results of our earlier pilot study and expanding the findings to the whole brain, patients with obsessive-compulsive disorder had significantly less total white matter but, in addition, significantly greater total cortex and opercular volumes. Severity of obsessive-compulsive disorder and nonverbal immediate memory correlated with opercular volume. CONCLUSIONS: Replication of volumetric white-matter differences suggests a widely distributed structural brain abnormality in obsessive-compulsive disorder. Whereas determining the etiogenesis may require research at a microscopic level, understanding its functional significance can be further explored via functional neuroimaging and neuropsychological studies.

Functional magnetic resonance imaging of symptom provocation in obsessive-compulsive disorder.

BACKGROUND: The new technique of functional magnetic resonance imaging was used to investigate the mediating neuroanatomy of obsessive-compulsive disorder symptoms. METHODS: Ten patients with obsessive-compulsive disorder and 5 normal subjects were studied via functional magnetic resonance imaging during control and provoked conditions. Data analysis entailed parametric and nonparametric statistical mapping. RESULTS: Statistical maps (nonparametric; P < 10(-3)) showed activation for 70% or more of patients with obsessive-compulsive disorder in medial orbitofrontal, lateral frontal, anterior temporal, anterior cingulate, and insular cortex, as well as caudate, lenticulate, and amygdala. No normal subjects exhibited activation in any brain region. CONCLUSIONS: Results of functional magnetic resonance imaging were consistent with past studies of obsessive-compulsive disorder that used other functional neuroimaging modalities. However, paralimbic and limbic activations were more prominent in the present study.

The functional neuroanatomy of anxiety: a study of three disorders using positron emission tomography and symptom provocation.

Previous neuroimaging research has contributed insights regarding the neural substrates of specific psychiatric disorders. The purpose of this study was to determine the shared mediating neuroanatomy of anxiety symptoms across three different anxiety disorders. Data were pooled from 23 right-handed adult outpatients meeting criteria for obsessive-compulsive disorder, simple phobia, or posttraumatic stress disorder. Relative regional cerebral blood flow (rCBF) was measured using positron emission tomography in the context of symptom provocation paradigms. Symptom severity was measured via self-reports. The analysis of pooled imaging data indicated activation in right inferior frontal cortex, right posterior medial orbitofrontal cortex, bilateral insular cortex, bilateral lenticulate nuclei, and bilateral brain stem foci during the symptomatic versus control conditions. A positive correlation was found between rCBF at one brain stem locus and subjective anxiety scores (r = .744, p < .001). These findings suggest that elements of the paralimbic belt together with right inferior frontal cortex and subcortical nuclei mediate symptoms across different anxiety disorders. In addition, activation at one brain stem locus appears to be associated with the subjective severity of anxiety. Further studies are warranted to determine whether these same brain systems mediate normal anxiety states as well.

The emotional counting Stroop paradigm: a functional magnetic resonance imaging probe of the anterior cingulate affective division.

BACKGROUND: The emotional counting Stroop (ecStroop) functional magnetic resonance imaging (fMRI) activation paradigm was designed to recruit the anterior cingulate affective division (ACad). METHODS: Nine normal, healthy male and female subjects (mean age 24.2 years) reported via button press the number of neutral and negative words that appeared on a screen while reaction time and fMRI data were acquired. RESULTS: We observed a) greater ACad activation for negative versus neutral words during initial presentation blocks; b) lower overall ACad signal intensity during task performance (i.e., both negative and neutral words) compared to the baseline fixation condition; and c) no reaction time increase to negative versus neutral words. CONCLUSIONS: In a companion study of a cognitive version of the counting Stroop (Bush et al 1998), these same 9 subjects a) activated the more dorsal anterior cingulate cognitive division; b) also showed the overall decrease in ACad signal intensity; and c) demonstrated a reliable reaction time effect. Taken together, these data offer a within-group spatial dissociation of AC function based upon information content (i.e., cognitive vs. emotional) and/or presence of behavioral interference. We propose that the ecStroop will be a useful fMRI probe of ACad function in anxiety disorders.

Low-level sensory processing in obsessive-compulsive disorder: an evoked potential study.

This study used visual and auditory evoked potentials (VEP and AEP) to study low-level sensory processing in a group of 15 unmedicated subjects with obsessive-compulsive disorder (OCD) and 30 age-matched, gender-matched, and handedness-matched normal controls. EPs were recorded to flash (VEP) and binaural click (AEP) stimulation. OCD subjects were found to have significantly shorter latencies on N1 and P2 of the AEP, and no differences were found in the VEP. Results indicate abnormal information processing states in OCD during low-level auditory processing, but not during low-level visual processing. Neural generators of the VEP and AEP are briefly reviewed and results are discussed in relation to current neurobiological models of OCD.

Organizational strategies mediate nonverbal memory impairment in obsessive-compulsive disorder.

BACKGROUND: Previous neuropsychological studies of obsessive-compulsive disorder (OCD) have indicated impaired executive functioning and nonverbal memory. The extent to which impaired executive functioning impacts nonverbal memory has not been established. The current study investigated the mediating effects of organizational strategies used when copying a figure on subsequent nonverbal memory for that figure. METHODS: We examined neuropsychological performance in 20 unmedicated subjects with OCD and 20 matched normal control subjects. Subjects were administered the Rey-Osterrieth Complex Figure Test (RCFT) and neuropsychological tests assessing various aspects of executive function. RESULTS: OCD subjects differed significantly from healthy control subjects in the organizational strategies used to copy the RCFT figure, and they recalled significantly less information on both immediate and delayed testing. Multiple regression analyses indicated that group differences in immediate percent recall were significantly mediated by copy organizational strategies. Further exploratory analyses indicated that organizational problems in OCD may be related to difficulties shifting mental and/or spatial set. CONCLUSIONS: Immediate nonverbal memory problems in OCD subjects were mediated by impaired organizational strategies used during the initial copy of the RCFT figure. Thus, the primary deficit was one affecting executive function, which then had a secondary effect on immediate memory. These findings are consistent with current theories proposing frontal-striatal system dysfunction in OCD.

Anterior cingulate cortex dysfunction in attention-deficit/hyperactivity disorder revealed by fMRI and the Counting Stroop.

BACKGROUND: The anterior cingulate cognitive division (ACcd) plays a central role in attentional processing by: 1) modulating stimulus selection (i.e., focusing attention) and/or 2) mediating response selection. We hypothesized that ACcd dysfunction might therefore contribute to producing core features of attention-deficit/hyperactivity disorder (ADHD), namely inattention and impulsivity. ADHD subjects have indeed shown performance deficits on the Color Stroop, an attentional/cognitive interference task known to recruit the ACcd. Recently, the Counting Stroop, a Stroop-variant specialized for functional magnetic resonance imaging (fMRI), produced ACcd activation in healthy adults. In the present fMRI study, the Counting Stroop was used to examine the functional integrity of the ACcd in ADHD. METHODS: Sixteen unmedicated adults from two groups (8 with ADHD and 8 matched control subjects) performed the Counting Stroop during fMRI. RESULTS: While both groups showed an interference effect, the ADHD group, in contrast to control subjects, failed to activate the ACcd during the Counting Stroop. Direct comparisons showed ACcd activity was significantly higher in the control group. ADHD subjects did activate a frontostriatal-insular network, indicating ACcd hypoactivity was not caused by globally poor neuronal responsiveness. CONCLUSIONS: The data support a hypothesized dysfunction of the ACcd in ADHD.

Reduced basal ganglia volumes in trichotillomania measured via morphometric magnetic resonance imaging.

A morphometric magnetic resonance imaging (MRI) study compared volumes of brain structures in 10 female subjects with trichotillomania (repetitive hair-pulling) versus 10 normal controls matched for sex, age, handedness, and education. Three-dimensional MRI scans were blindly normalized and segmented using well-characterized semiautomated intensity and differential contour algorithms by signal intensity-frequency histograms. Consistent with one a priori hypothesis, left putamen volume was found to be significantly smaller in trichotillomania subjects as compared with normal matched controls. This is the first report of a structural brain abnormality in trichotillomania. Results are discussed in terms of putative relationships between trichotillomania, Tourette's syndrome, and obsessive-compulsive disorder.

Cerebral metabolic correlates as potential predictors of response to anterior cingulotomy for obsessive compulsive disorder.

BACKGROUND: As interventions for severe, treatment-refractory obsessive compulsive disorder (OCD), neurosurgical procedures are associated with only modest efficacy. The purpose of this study was to identify cerebral metabolic correlates as potential predictors of treatment response to anterior cingulotomy for OCD. METHODS: Clinical data were analyzed in the context of a retrospective design. Subjects were 11 patients who underwent stereotactic anterior cingulotomy for OCD. Symptom severity was measured using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) before and at approximately 6 months postoperative. Preoperative F-18-fluorodeoxyglucose-positron emission tomography (FDG-PET) data were available. Statistical parametric mapping methods were used to identify loci of significant correlation between preoperative regional cerebral metabolism and postoperative reduction in Y-BOCS scores. RESULTS: One locus within right posterior cingulate cortex was identified, where preoperative metabolism was significantly correlated with improvement in OCD symptom severity following cingulotomy. Specifically, higher preoperative rates of metabolism at that locus were associated with better postoperative outcome. CONCLUSIONS: A possible predictor of treatment response was identified for patients with OCD undergoing anterior cingulotomy. Further research, utilizing a prospective design, is indicated to determine the validity and reliability of this finding. If confirmed, an index for noninvasively predicting response to cingulotomy for OCD would be of great value.

Monoamine oxidase inhibitors as treatment for depressed patients with primary degenerative dementia (Alzheimer's disease).

Two Alzheimer's patients with disabling depression failed to respond to standard antidepressants but improved with a monoamine oxidase inhibitor. The author points out that the cholinergic system is involved in Alzheimer's symptoms and that demented patients have high monoamine oxidase levels.

A case report of successful treatment of dysmorphophobia with tranylcypromine.

The author describes a 21-year-old woman with persistent disabling dysmorphophobia (atypical somatoform disorder) that failed to respond to neuroleptics and heterocyclic antidepressants but resolved completely with the monamine oxidase inhibitor tranylcypromine.