Action sequence learning, habits, and automaticity in obsessive-compulsive disorder

This study investigates the goal/habit imbalance theory of compulsion in obsessive-compulsive disorder (OCD), which postulates enhanced habit formation, increased automaticity, and impaired goal/habit arbitration. It directly tests these hypotheses using newly developed behavioral tasks. First, OCD patients and healthy participants were trained daily for a month using a smartphone app to perform chunked action sequences. Despite similar procedural learning and attainment of habitual performance (measured by an objective automaticity criterion) by both groups, OCD patients self-reported higher subjective habitual tendencies via a recently developed questionnaire. Subsequently, in a re-evaluation task assessing choices between established automatic and novel goal-directed actions, both groups were sensitive to re-evaluation based on monetary feedback. However, OCD patients, especially those with higher compulsive symptoms and habitual tendencies, showed a clear preference for trained/habitual sequences when choices were based on physical effort, possibly due to their higher attributed intrinsic value. These patients also used the habit-training app more extensively and reported symptom relief post-study. The tendency to attribute higher intrinsic value to familiar actions may be a potential mechanism leading to compulsions and an important addition to the goal/habit imbalance hypothesis in OCD. We also highlight the potential of smartphone app training as a habit reversal therapeutic tool.

The role of psychosis and clozapine load in excessive checking in treatment-resistant schizophrenia: longitudinal observational study

BACKGROUND

A significant proportion of people with clozapine-treated schizophrenia develop 'checking' compulsions, a phenomenon yet to be understood.

AIMS

To use habit formation models developed in cognitive neuroscience to investigate the dynamic interplay between psychosis, clozapine dose and obsessive-compulsive symptoms (OCS).

METHOD

Using the anonymised electronic records of a cohort of clozapine-treated patients, including longitudinal assessments of OCS and psychosis, we performed longitudinal multi-level mediation and multi-level moderation analyses to explore associations of psychosis with obsessiveness and excessive checking. Classic bivariate correlation tests were used to assess clozapine load and checking compulsions. The influence of specific genetic variants was tested in a subsample.

RESULTS

A total of 196 clozapine-treated individuals and 459 face-to-face assessments were included. We found significant OCS to be common (37.9%), with checking being the most prevalent symptom. In mediation models, psychosis severity mediated checking behaviour indirectly by inducing obsessions (r = 0.07, 95% CI 0.04-0.09; P < 0.001). No direct effect of psychosis on checking was identified (r = -0.28, 95% CI -0.09 to 0.03; P = 0.340). After psychosis remission (n = 65), checking compulsions correlated with both clozapine plasma levels (r = 0.35; P = 0.004) and dose (r = 0.38; P = 0.002). None of the glutamatergic and serotonergic genetic variants were found to moderate the effect of psychosis on obsession and compulsion (SLC6A4, SLC1A1 and HTR2C) survived the multiple comparisons correction.

CONCLUSIONS

We elucidated different phases of the complex interplay of psychosis and compulsions, which may inform clinicians' therapeutic decisions.

Excessive Checking in Obsessive-Compulsive Disorder: Neurochemical Correlates Revealed by 7T Magnetic Resonance Spectroscopy

Background

Compulsive checking, a common symptom of obsessive-compulsive disorder (OCD), has been difficult to capture experimentally. Therefore, determination of its neural basis remains challenging despite some evidence suggesting that it is linked to dysfunction of cingulostriatal systems. This study introduces a novel experimental paradigm to measure excessive checking and its neurochemical correlates.

Methods

Thirty-one patients with OCD and 29 healthy volunteers performed a decision-making task requiring them to decide whether 2 perceptually similar visual representations were the same or different under a high-uncertainty condition without feedback. Both groups underwent 7T magnetic resonance spectroscopy scans on the same day. Correlations between out-of-scanner experimental measures of checking and the glutamate/GABA (gamma-aminobutyric acid) ratio in the anterior cingulate cortex, supplementary motor area, and occipital cortex were assessed. Their relationship with subjective ratings of doubt, anxiety, and confidence was also investigated.

Results

Patients with OCD exhibited excessive and dysfunctional checking, which was significantly correlated with changes in the glutamate/GABA ratio within the anterior cingulate cortex. No behavioral/neurochemical relationships were evident for either the supplementary motor area or occipital cortex. The excessive checking observed in patients was negatively correlated with their confidence levels and positively related to doubt, anxiety, and compulsivity traits.

Conclusions

We conclude that experimental measures of excessive and dysfunctional checking in OCD, which have been linked to increased doubt, anxiety, and lack of confidence, are related to an imbalance between excitatory and inhibitory neural activity within the anterior cingulate cortex. This study adds to our understanding of the role of this region in OCD by providing a laboratory model of the possible development of compulsive checking.

Cortical glutamate and GABA are related to compulsive behaviour in individuals with obsessive compulsive disorder and healthy controls

There has been little analysis of neurochemical correlates of compulsive behaviour to illuminate its underlying neural mechanisms. We use 7-Tesla proton magnetic resonance spectroscopy (¹H-MRS) to assess the balance of excitatory and inhibitory neurotransmission by measuring glutamate and GABA levels in anterior cingulate cortex (ACC) and supplementary motor area (SMA) of healthy volunteers and participants with Obsessive-Compulsive Disorder (OCD). Within the SMA, trait and clinical measures of compulsive behaviour are related to glutamate levels, whereas a behavioural index of habitual control correlates with the glutamate:GABA ratio. Participants with OCD also show the latter relationship in the ACC while exhibiting elevated glutamate and lower GABA levels in that region. This study highlights SMA mechanisms of habitual control relevant to compulsive behaviour, common to the healthy sub-clinical and OCD populations. The results also demonstrate additional involvement of anterior cingulate in the balance between goal-directed and habitual responding in OCD.

Clozapine-related obsessive-compulsive symptoms and their impact on wellbeing: a naturalistic longitudinal study

BACKGROUND

Obsessive-compulsive symptoms (OCS) are commonly associated with clozapine treatment but are frequently overlooked by clinicians despite their potential impact on patients' quality of life. In this study, we explored whether OCS severity impacted subjective wellbeing and general functioning, independently of depressive and psychotic symptoms.

METHODS

We used anonymised electronic healthcare records from a large cohort of patients who were treated with clozapine and assessed annually for OCS, wellbeing, general functioning, and psychopathology using standardised scales as part of routine clinical practice. We used statistical mixed linear model techniques to evaluate the longitudinal influence of OCS severity on wellbeing and general functioning.

RESULTS

A total of 184 patients were included, with 527 face-to-face assessments and 64.7% evaluated three or more times. Different linear mixed models demonstrated that OCS in patients treated with clozapine were associated with significantly worse wellbeing scores, independently of depression and psychotic symptoms, but OCS did not impair general functioning. Obsessional thinking and hoarding behaviour, but not compulsions, were significantly associated with the impact on wellbeing, which may be attributable to the ego-syntonic nature of the compulsions.

CONCLUSIONS

Given the frequent occurrence of OCS and their negative impact on wellbeing, we encourage clinicians to routinely assess and treat OCS in patients who are taking clozapine.

Magnetic Resonance Spectroscopy (MRS) and Positron Emission Tomography (PET) Imaging in Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is characterised by structural and functional deficits in the cortico-striato-thalamic-cortical (CSTC) circuitry and abnormal neurochemical changes are thought to modulate these deficits. The hypothesis that an imbalanced concentration of the brain neurotransmitters, in particular glutamate (Glu) and gamma-amino-butyric acid (GABA), could impair the normal functioning of the CSTC, thus leading to OCD symptoms, has been tested in humans using magnetic resonance spectroscopy (MRS) and positron emission tomography (PET). This chapter summarises these neurochemical findings and represents an attempt to condense such scattered literature. We also discuss potential challenges in the field that may explain the inconsistent findings and suggest ways to overcome them. There is some convergent research from MRS pointing towards abnormalities in the brain concentration of neurometabolite markers of neuronal integrity, such as N-acetylaspartate (NAA) and choline (Cho). Lower NAA levels have been found in dorsal and rostral ACC of OCD patients (as compared to healthy volunteers), which increase after CBT and SSRI treatment, and higher Cho concentration has been reported in the thalamus of the OCD brain. However, findings for other neurometabolites are very inconsistent. Studies have reported abnormalities in the concentrations of creatine (Cr), GABA, glutamate (Glu), glutamine (Gln), Ins (myo-inositol), and serotonin (5-HT), but most of the results were not replicated. The question remains whether the NAA and Cho findings are genuinely the only neurochemical abnormalities in OCD or whether the lack of consistent findings for the other neurometabolites is caused by the lower magnetic field (1-3 Tesla (T)) used by the studies conducted so far, their small sample sizes or a lack of proper control for medication effects. To answer these questions and to further inform the biological underpinning of the symptoms and the cognitive problems at the basis of OCD we need better controlled studies using clear medicated vs unmedicated groups, larger sample sizes, stronger magnetic fields (e.g. at 7 T), and more consistency in the definition of the regions of interest.

A cross sectional study of impact and clinical risk factors of antipsychotic-induced OCD

A large proportion of schizophrenia patients treated with second generation antipsychotics will develop Obsessive Compulsive Disorder (OCD). However, there are few studies about the impact of this comorbidity and who is at higher risk. In this study of clozapine-treated patients, we aimed to determine the impact on outcome of clozapine-induced OCD, as well as the clinical and sociodemographic risk factors related to OCD-onset in clozapine patients. We had strict and novel inclusion criteria to minimise mis-identification of cases. The Obsessive-Compulsive Inventory-Revised (OCI-R) was used to divide 231 clozapine-treated patients into extreme cases of OCD (OCI  ≥ 24 or checking subscale ≥6) versus non-OCD (OCI <15 and checking subscale <4). The Global Assessment of Functioning (GAF), short version of Warwick-Edinburgh Wellbeing scale and Clinical Global Impression for schizophrenia (CGI) scales were used to determine outcome. Socio-demographic information was used to identify the risk factors for OCD development. We found that schizophrenia patients with OCD symptoms had a significantly lower patient rated wellbeing scores (p < 0.001) only (no difference in clinician rated wellbeing scores), higher CGI positive (p < 0.01) and higher CGI depressive scores (p < 0.05). The only risk factors that reached significance level were higher treatment dose (p < 0.01) and younger paternal age at birth (p < 0.05). There is scope for future studies based on e.g. imaging and genetic studies to further investigate causality, and in improving clinician screening for OCD.

Visual processing deficits in 22q11.2 Deletion Syndrome

Carriers of the rare 22q11.2 microdeletion present with a high percentage of positive and negative symptoms and a high genetic risk for schizophrenia. Visual processing impairments have been characterized in schizophrenia, but less so in 22q11.2 Deletion Syndrome (DS). Here, we focus on visual processing using high-density EEG and source imaging in 22q11.2DS participants (N = 25) and healthy controls (N = 26) with an illusory contour discrimination task.

Significant differences between groups emerged at early and late stages of visual processing. In 22q11.2DS, we first observed reduced amplitudes over occipital channels and reduced source activations within dorsal and ventral visual stream areas during the P1 (100–125 ms) and within ventral visual cortex during the N1 (150–170 ms) visual evoked components. During a later window implicated in visual completion (240–285 ms), we observed an increase in global amplitudes in 22q11.2DS. The increased surface amplitudes for illusory contours at this window were inversely correlated with positive subscales of prodromal symptoms in 22q11.2DS.

The reduced activity of ventral and dorsal visual areas during early stages points to an impairment in visual processing seen both in schizophrenia and 22q11.2DS. During intervals related to perceptual closure, the inverse correlation of high amplitudes with positive symptoms suggests that participants with 22q11.2DS who show an increased brain response to illusory contours during the relevant window for contour processing have less psychotic symptoms and might thus be at a reduced prodromal risk for schizophrenia.

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In schizophrenia, early visual processing is altered.

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22q11.2DS carriers have an increased risk for schizophrenia.

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Hd-EEG to investigate visual processing in an illusory contour task in 22q11.2DS.

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Occipital cortex activity is reduced in 22q11.2DS early in time.

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Both in 22q11.2DS and schizophrenia, early visual processing is impaired at P1.

Freeman-Sheldon syndrome: a case report

Freeman-Sheldon syndrome is a rare hereditary disorder characterised by three basic abnormalities, namely microstomia, camptodactyly with ulnar deviation of the fingers, and clubfoot. The majority of these patients have microstomia and dental crowding, making oral hygiene difficult and increasing the risk of caries. Treatment of these patients requires a coordinated effort by a team of specialists, including a paediatrician, an anaesthesiologist, a plastic surgeon, a paediatric dentist, and an orthodontist. Herein, we describe dental problems of a child with Freeman-Sheldon syndrome and the treatment procedures performed.

Determinants of Patient's Adherence to Hypertension Medications: Application of Health Belief Model Among Rural Patients

Background:

Hypertension is a major health problem in developing and developed countries, and its increasing epidemy is a serious warning to take more attention to this silent disease.

Aim:

This study was aimed to determine the factors of adherence to hypertension medication based on health belief model (HBM).

Subjects and Methods:

A cross-sectional study was conducted in a rural area of the Ardabil city in 2013. This study was carried out using a pre-structured and validated questionnaire. The questionnaire included information on demographic characteristics, lifestyle habits, HBM constructs and adherence to hypertension medication (Morisky 4-Item Self-Report Measure of Medication-taking Behavior [Morisky Medication Adherence Scale]). Data were analyzed with the use of SPSS version 18. P < 0.05 was considered as statistically significant.

Results:

A total of 671 hypertensive patients participated in the study (169 were males and 502 were females). The prevalence of adherence was 24% (161/671)% in the study population. Respondents with regular physical activity and nonsmokers were more adherent to hypertension medication when compared to respondents with sedentary lifestyle and smoking (P < 0.01). Based on HBM constructs, the respondents who perceived high susceptibility, severity, benefit had better adherence compared to moderate and low susceptibility, severity, and benefit.

Conclusion:

The prevalence of adherence to hypertension management was low in study population, this due to inadequate perceived susceptibility, perceived, severity, perceived benefit and poor lifestyle factors. Improving adherence in hypertension patients need to recognize the value and importance of patient perceptions medications.

Remineralization Effect of Topical NovaMin Versus Sodium Fluoride (1.1%) on Caries-Like Lesions in Permanent Teeth

OBJECTIVE

NovaMin, a synthetic mineral composed of calcium, sodium, phosphorous and silica releases deposits of crystalline hydroxyl-carbonate apatite (HCA) structurally similar to tooth mineral composition. The aim of this investigation was to compare the potential remineralization effect of topical NovaMin and Sodium Fluoride gel on caries like lesions in permanent teeth.

MATERIALS AND METHODS

A total of 60 sound human freshly extracted teeth were subjected to a pH-cycling protocol. Specimens were randomly assigned to one of the two treatment groups with NovaMin contained dentifrice applied to group 1, while group 2 received a dentifrice containing 1.1% neutral Sodium Fluoride. Pastes were applied five times after the samples received a demineralization from an earlier cariogenic challenge. Specimens were then evaluated by a Surface Micro Hardness test (SMH, 25G, 5s). Post-treatment SMH measurements were conducted and Mann Whitney test was employed for statistical analysis.

RESULTS

Mean post lesion SMH values were 221.99±26.27 and 224.50±28.64 for the first and second groups, respectively. Post treatment SMH values were 232.52±24.34 for NovaMin and 232.03 ±24.46 for the fluoride group. Two way ANOVA test showed a highly significant difference between the two different treatment protocols (p<0.001).

CONCLUSION

NovaMin dentifrice appears to have a greater effect on remineralization of carious-like lesions when compared to that of fluoride containing dentifrice in permanent teeth.

Comparison of plaque removal efficacy of new and 3-month-old toothbrushes in children

The cost of replacing toothbrushes at frequent intervals may be prohibitive in underdeveloped countries. The objective of this study in Tehran was to compare the plaque removal efficacy of new and 3-month-old toothbrushes in children. In a randomized, crossover study, 93 children aged 7-9 years old received a new manual toothbrush to use twice per day for 3 months. Plaque scores were measured using the modified Quigley-Hein plaque index after children had brushed for 60 seconds with either a new or their used toothbrush. Bristle wear of worn brushes was assessed by measuring brushing surface areas on digital images. Compared with new brushes in the same subjects, no statistically significant differences were found for plaque score reductions for 3-month-old toothbrushes exhibiting various degrees of wear. Worn toothbrushes are equally effective as new ones for children.