Nienke Vulink

Deep brain stimulation restores frontostriatal network activity in obsessive-compulsive disorder

Little is known about the underlying neural mechanism of deep brain stimulation (DBS). We found that DBS targeted at the nucleus accumbens (NAc) normalized NAc activity, reduced excessive connectivity between the NAc and prefrontal cortex, and decreased frontal low-frequency oscillations during symptom provocation in patients with obsessive-compulsive disorder. Our findings suggest that DBS is able to reduce maladaptive activity and connectivity of the stimulated region.

Dysfunctional Reward Circuitry in Obsessive-Compulsive Disorder

BACKGROUND Obsessive-compulsive disorder (OCD) is primarily conceived as an anxiety disorder but has features resembling addictive behavior. Patients with OCD may develop dependency upon compulsive behaviors because of the rewarding effects following reduction of obsession-induced anxiety. Reward processing is critically dependent on ventral striatal-orbitofrontal circuitry and brain imaging studies in OCD have consistently shown abnormal activation within this circuitry. This is the first functional imaging study to investigate explicitly reward circuitry in OCD. METHODS Brain activity during reward anticipation and receipt was compared between 18 OCD patients and 19 healthy control subjects, using a monetary incentive delay task and functional magnetic resonance imaging. Reward processing was compared between OCD patients with predominantly contamination fear and patients with predominantly high-risk assessment. RESULTS Obsessive-compulsive disorder patients showed attenuated reward anticipation activity in the nucleus accumbens compared with healthy control subjects. Reduced activity of the nucleus accumbens was more pronounced in OCD patients with contamination fear than in patients with high-risk assessment. Brain activity during reward receipt was similar between patients and control subjects. A hint toward more dysfunctional reward processing was found in treatment-resistant OCD patients who subsequently were successfully treated with deep brain stimulation of the nucleus accumbens. CONCLUSIONS Obsessive-compulsive disorder patients may be less able to make beneficial choices because of altered nucleus accumbens activation when anticipating rewards. This finding supports the conceptualization of OCD as a disorder of reward processing and behavioral addiction.

Dopaminergic activity in Tourette syndrome and obsessive-compulsive disorder

Tourette syndrome (TS) and obsessive-compulsive disorder (OCD) both are neuropsychiatric disorders associated with abnormalities in dopamine neurotransmission. Aims of this study were to quantify striatal D2/3 receptor availability in TS and OCD, and to examine dopamine release and symptom severity changes in both disorders following amphetamine challenge. Changes in [(11)C]raclopride binding potential (BP(ND)) were assessed using positron emission tomography before and after administration of d-amphetamine (0.3 mg kg(-1)) in 12 TS patients without comorbid OCD, 12 OCD patients without comorbid tics, and 12 healthy controls. Main outcome measures were baseline striatal D2/3 receptor BP(ND) and change in BP(ND) following amphetamine as a measure of dopamine release. Voxel-based analysis revealed significantly decreased baseline [(11)C]raclopride BP(ND) in bilateral putamen of both patient groups vs. healthy controls, differences being more pronounced in the TS than in the OCD group. Changes in BP(ND) following amphetamine were not significantly different between groups. Following amphetamine administration, tic severity increased in the TS group, which correlated with BP(ND) changes in right ventral striatum. Symptom severity in the OCD group did not change significantly following amphetamine challenge and was not associated with changes in BP(ND). This study provides evidence for decreased striatal D2/3 receptor availability in TS and OCD, presumably reflecting higher endogenous dopamine levels in both disorders. In addition, it provides the first direct evidence that ventral striatal dopamine release is related to the pathophysiology of tics.

Misophonia: Diagnostic Criteria for a New Psychiatric Disorder

Background Some patients report a preoccupation with a specific aversive human sound that triggers impulsive aggression. This condition is relatively unknown and has hitherto never been described, although the phenomenon has anecdotally been named misophonia. Methodology and Principal Findings 42 patients who reported misophonia were recruited by our hospital website. All patients were interviewed by an experienced psychiatrist and were screened with an adapted version of the Y-BOCS, HAM-D, HAM-A, SCL-90 and SCID II. The misophonia patients shared a similar pattern of symptoms in which an auditory or visual stimulus provoked an immediate aversive physical reaction with anger, disgust and impulsive aggression. The intensity of these emotions caused subsequent obsessions with the cue, avoidance and social dysfunctioning with intense suffering. The symptoms cannot be classified in the current nosological DSM-IV TR or ICD-10 systems. Conclusions We suggest that misophonia should be classified as a discrete psychiatric disorder. Diagnostic criteria could help to officially recognize the patients and the disorder, improve its identification by professional health carers, and encourage scientific research.

Deep Brain Stimulation Induces Striatal Dopamine Release in Obsessive-Compulsive Disorder

BACKGROUND Obsessive-compulsive disorder is a chronic psychiatric disorder related to dysfunctional dopaminergic neurotransmission. Deep brain stimulation (DBS) targeted at the nucleus accumbens (NAc) has recently become an effective treatment for therapy-refractory obsessive-compulsive disorder, but its effect on dopaminergic transmission is unknown. METHODS We measured the effects of NAc DBS in 15 patients on the dopamine D2/3 receptor availability in the striatum with [(123)I]iodobenzamide ([(123)I]IBZM) single photon emission computed tomography. We correlated changes in [(123)I]IBZM binding potential (BP) with plasma levels of homovanillic acid (HVA) and clinical symptoms. RESULTS Acute (1-hour) and chronic (1-year) DBS decreased striatal [(123)I]IBZM BP compared with the nonstimulated condition in the putamen. BP decreases were observed after 1 hour of stimulation, and chronic stimulation was related to concurrent HVA plasma elevations, implying DBS-induced dopamine release. BP decreases in the area directly surrounding the electrodes were significantly correlated with changes in clinical symptoms (45% symptom decrease). CONCLUSIONS NAc DBS induced striatal dopamine release, which was associated with increased HVA plasma levels and improved clinical symptoms, suggesting that DBS may compensate for a defective dopaminergic system.

Quetiapine augments the effect of citalopram in non-refractory obsessive-compulsive disorder: a randomized, double-blind, placebo-controlled study of 76 patients.

OBJECTIVE To assess the efficacy of quetiapine addition to citalopram in treatment-naive or medication-free obsessive-compulsive disorder (OCD) patients. METHOD Seventy-six patients who met DSM-IV criteria for OCD and who were drug-free or drug-naive at entry were randomly assigned in a 10-week, double-blind trial with citalopram (60 mg/day) plus quetiapine (300-450 mg/day) or placebo; treatment-refractory OCD patients were excluded. Of the 76 eligible patients, 66 patients completed the trial-31 in the quetiapine and 35 in the placebo group. The change from baseline to endpoint on the total Yale-Brown Obsessive Compulsive Scale (YBOCS) and the response to treatment in the quetiapine addition compared with the placebo addition group were the primary outcome measures. Response was defined as a 35% or greater reduction on the YBOCS and a Clinical Global Impressions-Improvement (CGI-I) score at endpoint of 1 or 2. The study was conducted from November 2003 to June 2005 at the University Medical Centre Utrecht, The Netherlands. RESULTS As measured by the mean reduction in YBOCS scores following an intent-to-treat, last-observation-carried-forward analysis, quetiapine addition (11.9) was significantly superior to placebo (7.8; p = .009). Quetiapine addition was also significantly superior to placebo on the CGI-I scale, with a mean +/- SD CGI-I score of 2.1 +/- 1.3 versus 1.4 +/- 1.2, respectively (p = .023). Quetiapine addition (N = 22, 69%) was also associated with a significantly greater number of patients responding to treatment compared with placebo addition (N = 15, 41%; p = .019). More patients receiving quetiapine (N = 8) than placebo (N = 2; NS) discontinued treatment due to adverse events. CONCLUSIONS The combination of quetiapine and citalopram was more effective than citalopram alone in reducing OCD symptoms in treatment-naive or medication-free OCD patients. TRIAL REGISTRATION www.trialregister.nl Identifier NTR116.

Update on Repetitive Transcranial Magnetic Stimulation in Obsessive-Compulsive Disorder: Different Targets

Obsessive-compulsive disorder (OCD) is a chronic, disabling disorder. Ten percent of patients remain treatment refractory despite several treatments. For these severe, treatment-refractory patients, repetitive transcranial magnetic stimulation (rTMS) has been suggested as a treatment option. Since 1997, in published trials, a total of 110 OCD patients have been treated with rTMS. This review aims to provide an update on rTMS treatment in patients with OCD. First, the mechanism of action is discussed, followed by the efficacy and side effects of rTMS at various brain targets, and finally implications for the future. Due to the lack of studies with comparable stimulation or treatment parameters and with reliable designs, it is difficult to draw clear conclusions. In general, rTMS appears to be effective in open-label studies; however, this has not yet been replicated in randomized, sham-controlled trials.

Review of atypical antipsychotics in anxiety.

Atypical antipsychotics are increasingly used for treatment of anxiety disorders, either in mono- or combination therapy. This is the first review reporting on the use of atypical antipsychotics in monotherapy or augmentation in patients with primary anxiety disorders or anxiety (disorders) comorbid to schizophrenia, bipolar disorder (BPD) and major depressive disorder (MDD). We included 49 open-label trials, 32 randomized, placebo-controlled trials (RCTpls) and five randomized controlled trials without placebo arm with almost 6000 patients (open-label: 1710, randomized: 4145). An increasing number of RCTpls show promising results in 27-71% of patients with primary or comorbid anxiety disorders who were treated with monotherapy atypical antipsychotics or augmentation therapy. However, methodological flaws of included studies may limit conclusions of this review and larger placebo-controlled trials are warranted comparing standard treatment with monotherapy and augmentation therapy of atypical antipsychotics and placebo. In addition, higher dropout rates and side effects from treatment with atypical antipsychotics may limit the use of atypical antipsychotics in patients with anxiety disorders.

Obsessive-compulsive disorder and female reproductive cycle events: results from the OCD and reproduction collaborative study.

Women with obsessive–compulsive disorder (OCD) often report that symptoms first appear or exacerbate during reproductive cycle events; however, little is known about these relationships. The goals of this study were to examine, in a US and a European female OCD sample, onset and exacerbation of OCD in reproductive cycle events, and to investigate the likelihood of repeat exacerbation in subsequent pregnancies and postpartum periods.

NMDA Receptor Antagonist Ketamine Impairs Feature Integration in Visual Perception

Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA) receptors in monkeys can abolish neural signals related to figure-ground segregation and feature integration. However, it is unknown whether this also affects perceptual integration itself. Therefore, we tested whether ketamine, a non-competitive NMDA receptor antagonist, reduces feature integration in humans. We administered a subanesthetic dose of ketamine to healthy subjects who performed a texture discrimination task in a placebo-controlled double blind within-subject design. We found that ketamine significantly impaired performance on the texture discrimination task compared to the placebo condition, while performance on a control fixation task was much less impaired. This effect is not merely due to task difficulty or a difference in sedation levels. We are the first to show a behavioral effect on feature integration by manipulating the NMDA receptor in humans.