A family-based association study of the glutamate transporter gene SLC1A1 in obsessive-compulsive disorder in 378 families.

SLC1A encodes the neuronal and epithelial glutamate transporter and was previously tested as a candidate for obsessive-compulsive disorder (OCD) by several research groups. Recently, three independent research groups reported significant association findings between OCD and several genetic variants in SLC1A1. This study reports the results from a family-based association study, which examined the association between 13 single nucleotide polymorphisms (SNPs) within or in proximity to the SLC1A1 gene. Although we did not replicate association findings for those significant SNPs reported by previous studies, our study indicated a strong association signal with the SNP RS301443 (P-value = 0.000067; Bonferroni corrected P-value = 0.0167) under a dominant model, with an estimated odds ratio of 3.5 (confidence interval: 2.66-4.50). Further, we conducted single SNP analysis after stratifying the full data set by the gender status of affected in each family. The P-value for RS301443 in families with the male affected was 0.00027, and the P-value in families with female affected was 0.076. The fact that we identified a signal which was not previously reported by the other research groups may be due to differences in study designs and sample ascertainment. However, it is also possible that this significant SNP may be part of a regulator for SLC1A1, given that it is roughly 7.5 kb away from the boundary of the SLC1A1 gene. However, this potential finding needs to be validated biologically. Further functional studies in this region are planned by this research group.

Gender differences in genetic linkage and association on 11p15 in obsessive-compulsive disorder families.

Several clinical and genetic studies have reported gender differences in obsessive-compulsive disorder (OCD). Previously, we conducted a linkage genome scan using multipoint allele-sharing methods to test for linkage in 219 families participating in the OCD Collaborative Genetics Study. When these families were stratified by proband's gender, suggestive linkage to chromosome 11p15 at marker D11S2362 (KAC(all) = 2.92, P = 0.00012) was detected in families with male probands, but not in the ones with female probands. We have since conducted fine mapping with a denser microsatellite marker panel in the region of 11p15, and detected a significant linkage signal at D11S4146 (KAC(all) = 5.08, P < 0.00001) in the families of male probands. Subsequently, 632 SNPs were genotyped spanning a 4.0 Mb region of the 1 LOD unit interval surrounding the linkage peak in the original families and an additional 165 families. Six SNPs were associated with OCD (P < 0.001): two SNPs were identified when all the families were included, and four SNPs only in male proband families. No SNP showed significant association with the OCD phenotype only in the families with a female proband. The results suggest a possible gender effect in the etiology of OCD.

Sapap3 and pathological grooming in humans: Results from the OCD collaborative genetics study.

SAP90/PSD95-associated protein (SAPAP) family proteins are post-synaptic density (PSD) components that interact with other proteins to form a key scaffolding complex at excitatory (glutamatergic) synapses. A recent study found that mice with a deletion of the Sapap3 gene groomed themselves excessively, exhibited increased anxiety-like behaviors, and had cortico-striatal synaptic defects, all of which were preventable with lentiviral-mediated expression of Sapap3 in the striatum; the behavioral abnormalities were also reversible with fluoxetine. In the current study, we sought to determine whether variation within the human Sapap3 gene was associated with grooming disorders (GDs: pathologic nail biting, pathologic skin picking, and/or trichotillomania) and/or obsessive-compulsive disorder (OCD) in 383 families thoroughly phenotyped for OCD genetic studies. We conducted family-based association analyses using the FBAT and GenAssoc statistical packages. Thirty-two percent of the 1,618 participants met criteria for a GD, and 65% met criteria for OCD. Four of six SNPs were nominally associated (P < 0.05) with at least one GD (genotypic relative risks: 1.6-3.3), and all three haplotypes were nominally associated with at least one GD (permuted P < 0.05). None of the SNPs or haplotypes were significantly associated with OCD itself. We conclude that Sapap3 is a promising functional candidate gene for human GDs, though further work is necessary to confirm this preliminary evidence of association.

Normal physiological emotions but differences in expression of conscious feelings in children with high-functioning autism.

To provide insight into what aspects of the emotional circuit might be affected in high-functioning autism, we measured indices of physiological emotions and of the expression of conscious feelings in 10 children with high-functioning autism or Asperger syndrome and 10 comparison participants. Pleasant, unpleasant, and neutral pictures were presented while skin conductance responses were measured. Self-report ratings of pleasantness and interestingness were taken between pictures. Skin conductance responses did not differ between the groups. Self report ratings were different, with the children with autism giving more similar answers to the two questions than the comparison children. Impairments in socio-emotional expression in autism may be related to deficits in perception and/or expression of conscious feelings; physiological emotions may be relatively preserved.

Neurotransmitters in anxiety.

The most predictable anxiolytic effects of neurotransmitters are linked to the activation of a gamma-aminobutyric acid (GABA)-ergic subsystem associated with specific benzodiazepine receptors. Recent studies have indicated that subtypes of benzodiazepine receptors may be associated specifically with anxiolytic actions. Animal studies suggest that some forms of anxiety are mediated through the noradrenergic system, but a recent study testing this hypothesis confirmed it only partially. Other data implicate the serotonergic system in at least some types of anxiety. Currently the role of other neurotransmitters, such as dopamine, histamine, acetylcholine, and peptides, appears to be minimal. Clinical responses to drugs suggest that existence of at least two types of anxiety disorders representing perhaps different psychobiologic mechanisms.

Is hyperarousal essential to obsessive-compulsive disorder? Diminished physiologic flexibility, but not hyperarousal, characterizes patients with obsessive-compulsive disorder.

OBJECTIVE: To examine the hypothesis that the pathologic features of obsessive-compulsive disorder (OCD) are facilitated by abnormal levels of arousal, we compared patients with OCD with controls on self-reports and psychophysiologic measures. METHODS: Twenty-three patients with OCD were compared with 21 controls on rating scales and on psychophysiologic measures (ie, heart interbeat interval, skin conductance, respiration, blood pressure, and electromyographic activity) during rest and during two psychologically stressful tasks. RESULTS: Patients rated themselves higher on psychic and somatic anxiety scales. Mean physiologic activities were not elevated at rest. During tasks, changes in electrodermal, cardiovascular (except blood pressure), and muscle activities were smaller in patients with OCD, indicating decreased physiologic flexibility. CONCLUSIONS: Hyperarousal, measured peripherally, is not an essential pathologic feature of OCD. Decreased physiologic flexibility indicates an anxiety-related, but not OCD-specific, impairment of psychophysiologic reactivity to one's environment.

Somatic manifestations in women with generalized anxiety disorder. Psychophysiological responses to psychological stress.

Generalized anxiety disorder is associated with symptoms that suggest heightened muscular tension and autonomic arousal. Since self-reports of physiological states in patients with anxiety disorder are frequently unreliable, we compared 20 female patients with generalized anxiety disorder with a matched group of nonanxious controls on a battery of psychophysiological assessments (skin conductance, heart interbeat interval, blood pressure, respiration, and forehead and gastrocnemius electromyographic activity). We found that during baseline patients with generalized anxiety disorder differed from controls on electromyographic, but not on autonomic, measures. During psychological stress tasks, patients with generalized anxiety disorder showed a weaker mean skin conductance response with a narrower range in both skin conductance and heart rate than controls. These findings suggest that sympathetic inhibition, rather than enhancement, occurs in patients with generalized anxiety disorder during performance stress.

Effects of clonidine on anxiety disorders.

To examine the role of the noradrenergic system in anxiety disorders, 23 patients (nine with generalized anxiety disorders and 14 with panic disorders) were studied for four weeks with clonidine hydrochloride, a predominantly presynaptic noradrenergic agonist, and with placebo. A double-blind crossover design was used. The effect of clonidine was comparable in both anxiety disorders and superior to placebo in patients who tolerated the drug. The conditions of 17% of the patients became worse with the medication. The main effect of clonidine was a decrease of anxiety attacks and "psychic" symptoms. Somatic symptoms were least affected. The complexity of the results may be explained through the postsynaptic effects of clonidine, which in part neutralize its presynaptic nonadrenergic effects. It may also indicate disturbances in other neurotransmitter systems that are not affected by clonidine.

Multicenter double-blind comparison of sertraline and desipramine for concurrent obsessive-compulsive and major depressive disorders.

BACKGROUND: Serotonin reuptake inhibitors (SRIs) have demonstrated consistent efficacy in the treatment of obsessive-compulsive disorder (OCD), while agents that are primarily norepinephrine reuptake inhibitors have not. Comparable efficacy has been demonstrated for SRI and non-SRI antidepressants in uncomplicated major depressive disorder (MDD). This multicenter trial is the first comparison of an SRI (sertraline) and a non-SRI antidepressant (desipramine) in the treatment of OCD with concurrent MDD. METHODS: One hundred sixty-six patients diagnosed using structured clinical interviews and recruited from 16 treatment sites were randomly assigned to double-blind treatment with either sertraline (up to 200 mg/d) or desipramine (up to 300 mg/d) over 12 weeks. Measures of severity of OCD and MDD symptoms, as well as adverse effects of the medications, were monitored over the course of the treatment period. RESULTS: Patients assigned to sertraline responded significantly better at end point on measures of OCD and MDD symptoms compared with patients assigned to desipramine. Sertraline was also associated with a significantly greater number of patients who achieved a "robust" improvement in OCD symptoms (> or =40% reduction) compared with desipramine. More patients receiving desipramine than sertraline discontinued treatment because of adverse events. CONCLUSIONS: The SRI sertraline was more effective in reducing MDD and OCD symptoms than the primarily norepinephrine reuptake inhibitor desipramine for patients with concurrent OCD and MDD.

A family study of obsessive-compulsive disorder.

BACKGROUND: The causes of obsessive-compulsive disorder (OCD) are as yet unknown. Evidence of familial aggregation is one approach for investigating the role of genetics in the etiology of this condition. The current study was conducted to determine ifOCD is familial and to investigate possible familial subtypes. METHODS: Eighty case probands were identified in 5 specialty OCD clinics and 73 community control probands were identified by random-digit dialing. These probands and their first-degree relatives (343 case and 300 control relatives) were blinded to group and evaluated by psychiatrists and doctoral-level clinical psychologists using semistructured instruments. Final diagnoses were assigned by a blinded-consensus procedure. The results were analyzed using logistic regression by the method of generalized estimating equations. RESULTS: The lifetime prevalence of OCD was significantly higher in case compared with control relatives (11.7% vs 2.7%) (P<.001). Case relatives had higher rates of both obsessions and compulsions; however, this finding is more robust for obsessions. Age at onset of obsessive-compulsive symptoms in the case proband was strongly related to familiality (odds ratio, 0.92; confidence interval, 0.85-0.99) (P = .05); no case of OCD symptoms was detected in the relatives of probands whose age at onset of symptoms was 18 years or older. Probands with tics or obsessive-compulsive personality disorder were not more likely to have relatives with OCD than those without these features. CONCLUSIONS: Obsessive-compulsive disorder is a familial disorder. Obsessions are more specific to the phenotype than are compulsions. Age at onset of OCD is valuable in characterizing a familial subtype.

Normal caudate nucleus in obsessive-compulsive disorder assessed by quantitative neuroimaging.

BACKGROUND: Prior neuroimaging studies have not consistently demonstrated a structural or functional abnormality of the caudate nucleus in patients with obsessive-compulsive disorder (OCD). However, there is theoretical support for some associated dysfunction of the caudate nucleus. METHODS: We examined volumes of the caudate nucleus and putamen with magnetic resonance imaging in 24 patients with adult-onset OCD and 21 control subjects, group-matched on age, race, education, and sex. Patients were relatively free from tics. To evaluate function (metabolism or blood flow) of the caudate nucleus, we performed a quantitative review, including a meta-analysis, of normalized data from functional neuroimaging studies that compared patients who had OCD with normal control subjects. RESULTS: All structural basal ganglia measures failed to exhibit differences between patients with OCD and matched normal control subjects. Patients did not demonstrate evidence of ventricular enlargement. Quantitative meta-analysis of the functional neuroimaging literature did not demonstrate a consistent abnormality of the caudate nucleus. CONCLUSIONS: We did not observe evidence of a structural abnormality of the caudate nucleus in patients with OCD. Prior reports of a structural aberration of the caudate nucleus were mixed. We also did not find strong support for relative caudate metabolic or perfusion dysfunction in the literature, although increased function in the frontal cerebral cortex was identified. The heterogeneous nature of this disorder may account for inconsistencies between studies. For example, ventricular enlargement or reduced caudate volume or blood flow might be evident in patients with soft neurological signs (eg, tics), while patients in the current study were relatively free from tics. Although theories of OCD suggest a dysfunction of the caudate nucleus, the structural and functional neuroimaging literature has not consistently verified this.

Effects of naloxone on normals and chronically anxious patients.

A significant number of normal and chronically anxious subjects were able to discriminate subjectively between a session in which they received naloxone and one which they received a placebo. However, affective and physiological measures did not differ significantly between the drug and placebo sessions. The weakness of the response makes it unlikely that a naloxone-responsive endogenous opioid system is substantially involved in the regulation of anxiety. An unexpected finding from the placebo session data was that, despite increased forehead muscle tension and high self-ratings of distress, chronically anxious subjects showed consistently stable sympathetic activity under resting conditions and mild stress, indicating the existence of a subgroup of generalized anxiety patients with low autonomic reactivity.

The effects of NMDA receptor blockade on the acquisition of a conditioned emotional response.

Excitatory amino acids, acting at the N-methyl-d-aspartate (NMDA) receptor, have been postulated to play an important role in the acquisition of behavior (learning). Previous studies have shown that some forms of response acquisition can be impaired by drugs that block the NMDA receptor. To determine whether excitatory amino acid blockade could also affect the ability to acquire an emotional response, the effects of the noncompetitive NMDA receptor antagonist MK-801 were studied on the development of response suppression under a conditioned emotional response (CER) procedure in the rat. The CER procedure progressively suppressed responding when saline was given prior to the eight daily sessions over which animals were initially exposed. Daily treatment with MK-801 blocked the development of response suppression. Thus, these data are consistent with the notion that excitatory amino acid blockade prevents or diminishes the development of a learned emotional response. This suggests a potential role for this receptor in the development of anxiety-related disorders in humans.

Somatic symptoms of anxiety: comparison of self-report and physiological measures.

The frequently reported absence of significant correlations between patient rating scales and physiological measures has led to the belief that patients cannot reliably perceive physiological changes that are experienced under conditions of stress. To determine whether or not this conclusion is justified for patients with clinical anxiety, self-reports and psychophysiological recordings were examined and compared in 20 patients suffering from generalized anxiety disorder. No systematic correlations were found between patient ratings and physiological measures of somatic symptomatology during periods of rest or psychological stress (Stroop Test). However, parallel directional changes in the two sets of measures were observed upon exposure to stress, indicating that patients could accurately report the direction, but not the degree, of changes in physical symptoms of anxiety. These results suggest that patient reports of physical symptoms such as sweating and rapid heart rate can be useful in clinical evaluation and research settings that do not require quantitative assessment of physiological activity.

Treatment effects of alprazolam and imipramine: physiological versus subjective changes in patients with generalized anxiety disorder.

The correspondence between changes in physiological activity and somatic symptom reports was assessed in generalized anxiety disorder patients treated with alprazolam or imipramine. After 6 weeks, the two medications produced comparable reductions in self-reported somatic symptoms. However, patients taking alprazolam showed decreases in systolic blood pressure, epinephrine, and norepinephrine, and patients taking imipramine showed increases in heart rate, blood pressure, electromyographic activity, and norepinephrine. Thus, though the physiological changes associated with alprazolam treatment were consistent with changes in symptom reports, treatment with imipramine produced a desynchrony: patients reported significant decreases in cardiovascular symptoms and muscle tension in spite of the fact that heart rate, blood pressure, and electromyographic activity increased. Possible explanations for this counterintuitive phenomenon are discussed.

The familial phenotype of obsessive-compulsive disorder in relation to tic disorders: the Hopkins OCD family study.

BACKGROUND: Obsessive-compulsive disorder (OCD) and tic disorders have phenomenological and familial-genetic overlaps. An OCD family study sample that excludes Tourette's syndrome in probands is used to examine whether tic disorders are part of the familial phenotype of OCD. METHODS: Eighty case and 73 control probands and their first-degree relatives were examined by experienced clinicians using the Schedule for Affective Disorders and Schizophrenia-Lifetime Anxiety version. DSM-IV psychiatric diagnoses were ascertained by a best-estimate consensus procedure. The prevalence and severity of tic disorders, age-at-onset of OCD symptoms, and transmission of OCD and tic disorders by characteristics and type of proband (OCD + tic disorder, OCD - tic disorder) were examined in relatives. RESULTS: Case probands and case relatives had a greater lifetime prevalence of tic disorders compared to control subjects. Tic disorders spanning a wide severity range were seen in case relatives; only mild severity was seen in control relatives. Younger age-at-onset of OCD symptoms and possibly male gender in case probands were associated with increased tic disorders in relatives. Although relatives of OCD + tic disorder and OCD - tic disorder probands had similar prevalences of tic disorders, this result is not conclusive. CONCLUSIONS: Tic disorders constitute an alternate expression of the familial OCD phenotype.

Major depression and cardiac autonomic control.

We investigated autonomic control of heart rate in patients with major depression, melancholic type. Twenty-three depressed inpatients who were being treated with tricyclic antidepressants and 23 depressed patients who were taking no medications were compared with age- and sex-matched control groups on resting cardiac vagal tone and heart rate. In unmedicated depressed patients, cardiac vagal tone was comparable to that of control subjects, but heart rate was significantly higher. This increase in heart rate may have been due to sympathetic activation caused by anxiety, since the depressed patients were significantly more anxious than the control subjects. Medicated patients exhibited diminished cardiac vagal tone and higher heart rate than unmedicated patients and controls. This was probably due to the anticholinergic effects of the antidepressants. Our findings suggest that cardiac vagal tone is not lower than normal in patients with depression, melancholic type.

The relationship of obsessive-compulsive disorder to possible spectrum disorders: results from a family study.

BACKGROUND: The familial relationship between obsessive-compulsive disorder (OCD) and "obsessive-compulsive spectrum" disorders is unclear. This study investigates the relationship of OCD to somatoform disorders (body dysmorphic disorder [BDD] and hypochondriasis), eating disorders (e.g., anorexia nervosa and bulimia nervosa), pathologic "grooming" conditions (e.g., nail biting, skin picking, trichotillomania), and other impulse control disorders (e.g., kleptomania, pathologic gambling, pyromania) using blinded family study methodology. METHODS: Eighty case and 73 control probands, as well as 343 case and 300 control first-degree relatives, were examined by psychiatrists or Ph.D. psychologists using the Schedule for Affective Disorders and Schizophrenia-Lifetime Anxiety version. Two experienced psychiatrists independently reviewed all diagnostic information and made final consensus diagnoses using DSM-IV criteria. RESULTS: Body dysmorphic disorder, hypochondriasis, any eating disorder, and any grooming condition occurred more frequently in case probands. In addition, BDD, either somatoform disorder, and any grooming condition occurred more frequently in case relatives, whether or not case probands also had the same diagnosis. CONCLUSIONS: These findings indicate that certain somatoform and pathologic grooming conditions are part of the familial OCD spectrum. Though other "spectrum" conditions may resemble OCD, they do not appear to be important parts of the familial spectrum.

Serotonergic (5-HT2) mediation of anxiety-therapeutic effects of serazepine in generalized anxiety disorder.

Serotonin 1a and serotonin-2 receptors are implicated in anxiety. Serazepine (CGS-15040A, (R,S)-1,3,4,16b-Tetrahydro-2-methyl-2H,10H-indolo[2,1-c] Pyrazino-[1,2-a][1,4] benzodiazepine-16-carboxylic acid, methyl ester hydrochloride]) is a representative of a novel pentacyclic ring system containing a stabilized indole. In chemical assays it was a highly specific inhibitor of serotonin (5-HT2) binding, and it was active in preliminary preclinical assays of anxiolytic potential. This multicenter trial of CGS-15040A in patients with generalized anxiety disorder demonstrated clinical anxiolytic effects consistent with established preclinical effects. Doses greater than or equal to 10 mg reduced Hamilton Anxiety Scale scores. However, the dose-response relationship was nonlinear. Effects appeared primarily related to the psychic components of anxiety.

Symptoms and treatment responses of generalized anxiety disorder patients with high versus low levels of cardiovascular complaints.

Clinical observations suggest that patients with generalized anxiety disorder differ in somatic symptoms. The authors compared 28 patients with generalized anxiety disorder who had high levels of cardiovascular complaints with 32 patients with generalized anxiety disorder who had low levels of cardiovascular complaints on rating instruments, physiological measures, and use of anxiolytic medication. The two groups differed on somatic but not psychic symptoms on rating instruments. Patients with high levels of cardiovascular symptoms had higher levels of cardiac lability and required higher doses of alprazolam. These findings suggest that anxious patients with comparable levels of psychic anxiety may differ in levels of physical symptoms.