Neurophysiological Correlates of Anhedonia in Feedback Processing.

Neurophysiological correlates of anhedonia in feedback processing.

Front Hum Neurosci. 2013; 7: 96
Mies GW, Van den Berg I, Franken IH, Smits M, Van der Molen MW, Van der Veen FM

Disturbances in feedback processing and a dysregulation of the neural circuit in which the cingulate cortex plays a key role have been frequently observed in depression. Since depression is a heterogeneous disease, instead of focusing on the depressive state in general, this study investigated the relations between the two core symptoms of depression, i.e., depressed mood and anhedonia, and the neural correlates of feedback processing using fMRI. The focus was on the different subdivisions of the anterior cingulate cortex (ACC). Undergraduates with varying levels of depressed mood and anhedonia performed a time-estimation task in which they received positive and negative feedback that was either valid or invalid (i.e., related vs. unrelated to actual performance). The rostral cingulate zone (RCZ), corresponding to the dorsal part of the ACC, was less active in response to feedback in more anhedonic individuals, after correcting for the influence of depressed mood, whereas the subgenual ACC was more active in these individuals. Task performance was not affected by anhedonia, however. No statistically significant effects were found for depressed mood above and beyond the effects of anhedonia. This study therefore implies that increasing levels of anhedonia involve changes in the neural circuitry underlying feedback processing. HubMed – depression


Inferring about individual drug and schizotypy effects on cognitive functioning in polydrug using mephedrone users before and after clubbing.

Hum Psychopharmacol. 2013 Mar; 28(2): 168-82
Herzig DA, Brooks R, Mohr C

Mephedrone has been recently made illegal in Europe, but little empirical evidence is available on its impact on human cognitive functions. We investigated acute and chronic effects of mephedrone consumption on drug-sensitive cognitive measures, while also accounting for the influence of associated additional drug use and personality features.Twenty-six volunteers from the general population performed tasks measuring verbal learning, verbal fluency and cognitive flexibility before and after a potential drug-taking situation (pre-clubbing and post-clubbing at dance clubs, respectively). Participants also provided information on chronic and recent drug use, schizotypal (Oxford-Liverpool Inventory of Feelings and Experiences) and depressive symptoms (Beck Depression Inventory), sleep pattern and premorbid IQ.We found that (i) mephedrone users performed worse than non-users pre-clubbing and deteriorated from the pre-clubbing to the post-clubbing assessment; (ii) pre-clubbing cannabis and amphetamine (not mephedrone) use predicted relative cognitive attenuations; (iii) post-clubbing, depression scores predicted relative cognitive attenuations; and (iv) schizotypy was largely unrelated to cognitive functioning, apart from a negative relationship between cognitive disorganisation and verbal fluency.Results suggest that polydrug use and depressive symptoms in the general population negatively affect cognition. For schizotypy, only elevated cognitive disorganisation showed potential links to a pathological cognitive profile previously reported along the psychosis dimension. Copyright © 2013 John Wiley & Sons, Ltd. HubMed – depression


Efficacy of the novel antidepressant agomelatine for anxiety symptoms in major depression.

Hum Psychopharmacol. 2013 Mar; 28(2): 151-9
Stein DJ, Picarel-Blanchot F, Kennedy SH

Anxiety in major depression is associated with increased morbidity. The antidepressant, agomelatine, which acts as an agonist at melatonin MT1 and MT2 receptors and as an antagonist at serotonin 5-HT2C receptors, has demonstrated efficacy and safety in both major depression and generalized anxiety disorder. Here, we investigated the efficacy of agomelatine in anxious depression.Data from three placebo-controlled short-term trials of agomelatine and three comparative studies of agomelatine versus fluoxetine, sertraline, and venlafaxine were pooled. Effects of agomelatine on anxiety symptoms were assessed with the Hamilton Anxiety Rating Scale in four studies (one vs placebo and three vs active comparator) and with the Hamilton Depression Rating Scale (HAMD) anxiety subscore in all six studies. Anxiolytic and antidepressant efficacies of agomelatine were assessed in patients with more severe anxiety symptoms at baseline (score ?5 on HAMD anxiety subscore).Agomelatine had a significantly greater effect on anxiety symptoms than both placebo and a number of comparator antidepressants. In more anxious depressed patients, agomelatine had a significantly greater effect on anxiety and depressive symptoms than both placebo and comparator antidepressants.Once-a-day oral agomelatine is a new, efficacious alternative option for the treatment of anxiety in patients with major depression. Copyright © 2013 John Wiley & Sons, Ltd. HubMed – depression