Empirical investigations of thought suppression in OCD

Cognitive-behavioural models of obsessive-compulsive disorder (OCD) implicate thought suppression as a key factor in the development and persistence of the disorder. There is now more than a decade of research on thought suppression and its effects as they pertain to OCD. This paper briefly reports on initial thought suppression research and then offers a detailed review of recent thought suppression research that has directly examined the role of suppression in OCD. Theoretical and methodological issues in using thought suppression paradigms to understand OCD are discussed. It is concluded that this body of work continues to yield inconsistent findings with respect to the effects of suppression on thought frequency, although there are some consistent findings that suggest that suppression is driven by negative thought appraisal and is associated in turn with greater OCD symptomatology. Thus, there is support in this work for key tenets of cognitive-behavioural models of OCD. Suggestions for future research directions are offered.     

The importance of importance in OCD memory research

Investigations of memory and associated phenomena in obsessive-compulsive disorder (OCD) can advance our understanding of this often debilitating problem. Theoretical models predict both the presence and absence of memory biases in favour of threat-relevant information in association with anxiety disorders generally, and with OCD specifically. Two previous experiments (one involving compulsive washing and another involving compulsive checking) that demonstrated such a memory bias are reviewed in the context of the existing literature. Additionally, a new experiment failing to demonstrate such a bias (in association with compulsive ordering and arranging) is presented. The results are discussed in terms of cognitive-behavioural and information processing approaches to understanding OCD. It is argued that experiments which utilize stimuli that are low in ecological validity are unlikely to detect explicit memory biases in OCD. As such, experimental paradigms that are perceived as particularly significant, relevant and important to participants with OCD are encouraged.     

Amisulpiride augmentation in treatment resistant obsessive-compulsive disorder: an open trial

Despite the effectiveness of clomipramine and selective serotonin reuptake inhibitors (SSRIs) in the treatment of obsessive-compulsive disorder (OCD), 40% to 60% of patients who receive an adequate treatment with these agents have significant persisting symptoms. Newer atypical antipsychotic drugs showed efficacy as augmenting agents in patients with OCD resistant to serotonin reuptake inhibitors (SRIs). The objective of this study was to evaluate the efficacy and safety of amisulpiride augmentation in treatment resistant OCD. A total of 20 patients diagnosed with OCD according to DSM-IV criteria and having a history of resistance to treatment with SRIs were included in the study. Amisulpiride 200 mg/day was added to ongoing SRI treatment and titrated up to 600 mg/day in flexible doses. The mean amisulpiride dose was 325 +/- 106 mg/day. The patients were assessed with the Yale-Brown obsessive-compulsive scale (Y-BOCS) at baseline and at week 12 of amisulpiride treatment. Side effects were monitored by the UKU side effect rating scale. The reduction in Y-BOCS scores between the baseline (26.7 +/- 6.3) and the end of the treatment (12.5 +/- 2.8) was statistically significant (p=0.0001). The most commonly observed side effects included weight gain (14 patients, 70%), mild sedation (13 patients, 65%) and asthenia (7 patients, 35%). This study has several limitations and, hence, the results are preliminary and require confirmation in a randomized controlled trial. In conclusion, this study suggests that amisulpiride may be a promising option as an augmentation strategy in treatment resistant OCD.     

Latest view on the mechanism of action of deep brain stimulation

How does deep brain stimulation (DBS) applied at high frequency (100 Hz and above, HFS) in diverse points of cortico‐basal ganglia thalamo‐cortical loops alleviate symptoms of neurological disorders such as Parkinson's disease, dystonia, and obsessive compulsive disorders? Do the effects of HFS stem solely or even largely from local effects on the stimulated brain structure or are they also mediated by actions of HFS on distal structures? Indeed, HFS as an extracellular stimulation is expected to activate subsets of both afferent and efferent axons, leading to antidromic spikes that collide with ongoing spontaneous ones and orthodromic spikes that evoke synaptic responses in target neurons. The present review suggests that HFS interfere with spontaneous pathological patterns by introducing a regular activity in several nodal points of the network. Therefore, the best site of implantation of the HFS electrode may be in a region where the HFS‐driven activity spreads to most of the identified, dysrhythmic, neuronal populations without causing additional side effects. This should help tackling the most difficult issue namely, how does the regular HFS‐driven activity that dampens the spontaneous pathological one, restore neuronal processing along cortico‐basal ganglia‐thalamo‐cortical loops? © 2008 Movement Disorder Society     

Investigation of Cortical Glutamate–Glutamine and γ-Aminobutyric Acid in Obsessive–Compulsive Disorder by Proton Magnetic Resonance Spectroscopy

Glutamatergic abnormalities in corticostriatal brain circuits are thought to underlie obsessive–compulsive disorder (OCD). Whether these abnormalities exist in adults with OCD is not clear. We used proton magnetic resonance spectroscopy (¹H MRS) to test our hypothesis that unmedicated adults with OCD have reduced glutamate plus glutamine (Glx) levels in the medial prefrontal cortex (MPFC) compared with healthy controls. Levels of γ-aminobutyric acid (GABA) were also explored. Twenty-four unmedicated adults with OCD and 22 matched healthy control subjects underwent ¹H MRS scans at 3.0 T. Resonances of both Glx and GABA were obtained using the standard J-editing technique and assessed as ratios relative to voxel tissue water (W) in the MPFC (the region of interest) and the dorsolateral prefrontal cortex (DLPFC) to explore the regional specificity of any finding. In the MPFC, Glx/W did not differ by diagnostic group (p=0.98) or sex (p=0.57). However, GABA/W was decreased in OCD (2.16±0.46 × 10⁻³) compared with healthy controls (2.43±0.45 × 10⁻³, p=0.045); moreover, age of OCD onset was inversely correlated with MPFC GABA/W (r=−0.50, p=0.015). MPFC GABA/W was higher in females than in males. In the DLPFC, there were no main effects of diagnosis or gender on Glx/W or GABA/W. These data indicate that unmedicated adults with OCD do not have Glx abnormalities in a MPFC voxel that includes the pregenual anterior cingulate cortex. However, they may have decreased MPFC GABA levels. How GABA abnormalities might contribute to corticostriatal dysfunction in OCD deserves further study.     

Preparing the ethical future of deep brain stimulation

Background

Deep brain stimulation is an approved and effective neurosurgical intervention for motor disorders such as PD and ET. Deep brain stimulation may also be effective in treating a number of psychiatric disorders, including treatment refractory depression and OCD. Although DBS is a widely accepted therapy in motor disorders, it remains an invasive and expensive procedure. The ethical and social challenges of DBS need further examination, and discussion and emerging applications of DBS in psychiatry may also complicate the ethical landscape of DBS.

Methods

To identify and characterize current and emerging issues in the use of DBS, we reviewed the neurosurgical literature on DBS as well as the interdisciplinary medical ethics and relevant psychological and sociological literatures. We also consulted the USPTO database, FDA regulations and report decisions, and the business reports of key DBS manufacturers.

Results

Important ethical and social challenges exist in the current and extending practice of DBS, notably in patient selection, informed consent, resource allocation, and in public understanding. These challenges are likely to be amplified if emerging uses of DBS in psychiatry are approved.

Conclusions

Our review of ethical and social issues related to DBS highlights that several significant challenges, although not insurmountable, need much closer attention. A combination of approaches previously used in neuroethics, such as expert consensus workshops to establish ethical guidelines and public engagement to improve public understanding, may be fruitful to explore.     

Correlation between lipid peroxidation-induced TBARS level and disease severity in obsessive–compulsive disorder

Oxidative stress is thought to play an important role in several neuropsychiatric diseases including obsessive–compulsive disorder (OCD). Thiobarbituric acid reacting substances (TBARS) are products formed as a result of free radical induced lipid peroxidation in the human body. Our study investigated the correlation between TBARS and the clinical severity of OCD as indicated by the Yale Brown Obsessive Compulsive Scale (YBOCS). Serum TBARS was estimated in thirty nine newly diagnosed drug free OCD patients and thirty three disease free control subjects. Mean values for serum TBARS were found to be significantly higher (P < 0.001) in cases than in controls (5.85 nmol/ml and 3.90 nmol/ml with an SD of 0.56 and 0.81 respectively). A strong positive correlation (r_s = 0.757, p < 0.01) between the lipid peroxidation marker TBARS and the disease severity indicator YBOCS was found among cases. Significant positive correlation was also found between TBARS and the obsessive and compulsive subscales of YBOCS. These findings were in tune with previous studies, which suggested oxidative stress induced increased free radical generation in the OCD patients. Our findings may help in understanding the development and progress of OCD and the treatment of patients of OCD in future.     

Paroxetine treatment of compulsive hoarding

OBJECTIVE: Compulsive hoarding, found in many patients with obsessive-compulsive disorder (OCD), has been associated with poor response to serotonin reuptake inhibitor (SRI) medications in some reports. However, no prior study has quantitatively measured response to standardized pharmacotherapy in compulsive hoarders. We sought to determine whether compulsive hoarders would respond as well as non-hoarding OCD patients to the SRI, paroxetine. METHODS: Seventy-nine patients with OCD (32 patients with the compulsive hoarding syndrome and 47 patients without prominent hoarding symptoms) were treated openly with paroxetine (mean dose 41.6+/-12.8 mg/day; mean duration 80.4+/-23.5 days) according to a standardized protocol, from 3/1993 to 7/2005. All subjects were free of psychotropic medication for at least four weeks prior to study entry. No psychotherapy or psychotropic medications except paroxetine were allowed during the study period. Subjects were assessed before and after treatment with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Scale (Ham-A), Global Assessment Scale (GAS), and Clinical Global Impression/Improvement (CGI) scale. RESULTS: Both compulsive hoarders and non-hoarding OCD patients improved significantly with treatment (p<0.001), with nearly identical changes in Y-BOCS, HDRS, Ham-A, and GAS scores. There were no significant differences between groups in the proportions of patients who completed or responded to treatment. Hoarding symptoms improved as much as other OCD symptoms. CONCLUSIONS: Compulsive hoarders responded as well to paroxetine treatment as non-hoarding OCD patients, suggesting that SRI medications are effective for compulsive hoarding. Controlled trials of SRI medications for compulsive hoarding are now warranted.