Relationship between daily rated depression symptom severity and the retrospective self-report on PHQ-9: A prospective ecological momentary assessment study on 80 psychiatric outpatients.

BACKGROUND: Depression-related negative bias in emotional processing and memory may bias accuracy of recall of temporally distal symptoms. We tested the hypothesis that when responding to the Patient Health Questionnaire (PHQ-9) the responses reflect more accurately temporally proximal than distal mood states. METHODS: Currently, depressed psychiatric outpatients (N = 80) with depression confirmed in semi-structured interviews had the Aware application installed on their smartphones for ecological momentary assessment (EMA). The severity of "low mood", "hopelessness", "low energy", "anhedonia", and "wish to die" was assessed on a Likert scale five times daily during a 12-day period, and thereafter, the PHQ-9 questionnaire was completed. We used auto- and cross-correlation analyses and linear mixed-effects multilevel models (LMM) to investigate the effect of time lag on the association between EMA of depression symptoms and the PHQ-9. RESULTS: Autocorrelations of the EMA of depressive symptom severity at two subsequent days were strong (r varying from 0.7 to 0.9; p < 0.001). "Low mood" was the least and "wish to die" the most temporally stable symptom. The correlations between EMA of depressive symptoms and total scores of the PHQ-9 were temporally stable (r from 0.3 to 0.6; p < 0.001). No effect of assessment time on the association between EMA data and the PHQ-9 emerged in the LMM. LIMITATIONS: Altogether 11.5 % of observations were missing. CONCLUSIONS: Despite fluctuations in severity of some of the depressive symptoms, patients with depression accurately recollect their most dominant symptoms, without a significant recall bias favouring the most recent days, when responding to the PHQ-9.

Escitalopram enhances synchrony of brain responses during emotional narratives in patients with major depressive disorder.

One-week treatment with escitalopram decreases amygdala responses to fearful facial expressions in depressed patients, but it remains unknown whether it also modulates processing of complex and freely processed emotional stimuli resembling daily life emotional situations. Inter-subject correlation (ISC) offers a means to track brain activity during complex, dynamic stimuli in a model-free manner. Twenty-nine treatment-seeking patients with major depressive disorder were randomized in a double-blind study design to receive either escitalopram or placebo for one week, after which functional magnetic resonance imaging (fMRI) was performed. During fMRI the participants listened to spoken emotional narratives. Level of ISC between the escitalopram and the placebo group was compared across all the narratives and separately for the episodes with positive and negative valence. Across all the narratives, the escitalopram group had higher ISC in the default mode network of the brain as well as in the fronto-temporal narrative processing regions, whereas lower ISC was seen in the middle temporal cortex, hippocampus and occipital cortex. Escitalopram increased ISC during positive parts of the narratives in the precuneus, medial prefrontal cortex, anterior cingulate and fronto-insular cortex, whereas there was no significant synchronization in brain responses to positive vs negative events in the placebo group. Increased ISC may imply improved emotional synchronization with others, particularly during observation of positive events. Further studies are needed to test whether this contributes to the later therapeutic effect of escitalopram.

Reduced visual contrast suppression during major depressive episodes.

Background: Previous studies have suggested that processing of visual contrast information could be altered in major depressive disorder. To clarify the changes at different levels of the visual hierarchy, we behaviourally measured contrast perception in 2 centre-surround conditions, assessing retinal and cortical processing. Methods: As part of a prospective cohort study, our sample consisted of controls (n = 29; 21 female) and patients with unipolar depression, bipolar disorder and borderline personality disorder who had baseline major depressive episodes (n = 111; 74 female). In a brightness induction test that assessed retinal processing, participants compared the perceived luminance of uniform patches (presented on a computer screen) as the luminance of the backgrounds was varied. In a contrast suppression test that assessed cortical processing, participants compared the perceived contrast of gratings, which were presented with collinearly or orthogonally oriented backgrounds. Results: Brightness induction was similar for patients with major depressive episodes and controls (p = 0.60, d = 0.115, Bayes factor = 3.9), but contrast suppression was significantly lower for patients than for controls (p < 0.006, d = 0.663, Bayes factor = 35.2). We observed no statistically significant associations between contrast suppression and age, sex, or medication or diagnostic subgroup. At follow-up (n = 74), we observed some normalization of contrast perception. Limitations: We assessed contrast perception using behavioural tests instead of electrophysiology. Conclusion: The reduced contrast suppression we observed may have been caused by decreased retinal feedforward or cortical feedback signals. Because we observed intact brightness induction, our results suggest normal retinal but altered cortical processing of visual contrast during a major depressive episode. This alteration is likely to be present in multiple types of depression and to partially normalize upon remission.

Short-term escitalopram treatment normalizes aberrant self-referential processing in major depressive disorder.

BACKGROUND: Increased self-focus and negative self-concept play an important role in depression. Antidepressants influence self-referential processing in healthy volunteers, but their function in self-processing of depressed patients remains unknown. METHODS: Thirty-two depressed patients were randomly allocated to receive either escitalopram 10 mg or placebo for one week. After one week, neural responses to positive and negative self-referential adjectives and neutral control stimuli were assessed with functional magnetic resonance imaging. A group of matched healthy volunteers served as a control group. RESULTS: Escitalopram decreased responses of medial fronto-parietal regions to self-referential words relative to non-emotional control stimuli, driven by increased responses to the control condition. Escitalopram also increased responses in the pre-defined region of the medial prefrontal cortex (MPFC) and the anterior cingulate cortex (ACC) to positive relative to negative words. Importantly, the changes in neural responses occurred before any effect on depressive symptoms, implying a direct effect of escitalopram. Furthermore, the placebo group had decreased responses of the MPFC and the ACC to positive self-referential processing relative to the matched healthy controls. However, neural responses of the escitalopram group and the healthy unmedicated controls were similar. LIMITATIONS: Differences between the groups in self-reported depression symptoms and personality traits may have influenced the results. CONCLUSION: One-week treatment with escitalopram normalized aberrant self-referential processing in depressed patients, shifting the focus from the self to the external environment and potentiating positive self-referential processing. This may be an important factor in mechanism of action of antidepressants.

Single dose of mirtazapine modulates whole-brain functional connectivity during emotional narrative processing.

The link between neurotransmitter-level effects of antidepressants and their clinical effect remain poorly understood. A single dose of mirtazapine decreases limbic responses to fearful faces in healthy subjects, but it is unknown whether this effect applies to complex emotional situations and dynamic connectivity between brain regions. Thirty healthy volunteers listened to spoken emotional narratives during functional magnetic resonance imaging (fMRI). In an open-label design, 15 subjects received 15mg of mirtazapine two hours prior to fMRI while 15 subjects served as a control group. We assessed the effects of mirtazapine on regional neural responses and dynamic functional connectivity associated with valence and arousal. Mirtazapine attenuated responses to unpleasant events in the right fronto-insular cortex, while modulating responses to arousing events in the core limbic regions and the cortical midline structures (CMS). Mirtazapine decreased responses to unpleasant and arousing events in sensorimotor areas and the anterior CMS implicated in self-referential processing and formation of subjective feelings. Mirtazapine increased functional connectivity associated with positive valence in the CMS and limbic regions. Mirtazapine triggers large-scale changes in regional responses and functional connectivity during naturalistic, emotional stimuli. These span limbic, sensorimotor, and midline brain structures, and may be relevant to the clinical effectiveness of mirtazapine.

A single dose of mirtazapine attenuates neural responses to self-referential processing.

Increased self-focus is a core factor in the psychopathology of depression. Cortical midline structures (CMS) are implicated in the neurobiology of self, depression and antidepressant treatment response. Mirtazapine, an antidepressant that increases serotonin and norepinephrine release, enhances processing of positive and attenuates processing of negative emotional information in healthy volunteers after a single dose. These early changes, which are opposite to the negative information bias in depression, may be important for the therapeutic effect of mirtazapine. It nevertheless remains unresolved whether/how mirtazapine specifically influences processing of self-referential emotional information.Half of the healthy volunteers (n=15/30) received a single dose of mirtazapine, in an open-label design, two hours before functional magnetic resonance imaging (fMRI), and the other half was scanned as a control group without medication. During fMRI the participants categorized positive and negative self-referential adjectives.Mirtazapine attenuated responses to self-referential processing in the medial prefrontal cortex and the anterior cingulate cortex. Mirtazapine further decreased responses to positive self-referential processing in the posterior cingulate cortex and parietal cortex.These decreased responses of the CMS suggest that mirtazapine may rapidly improve the ability of the CMS to down-regulate self-referential processing. In depressed patients, this could lead to decreased self-focus and rumination, contributing to the antidepressant effect.

Sound energy and the magnitude of change: effects on mismatch negativity.

The mismatch negativity (MMN) of event-related potential generally increases in amplitude, as a function of magnitude of change. This study examined whether this relation holds true for intensity decrement, in which the stimulus energy that conveys the change falls in inverse proportion to magnitude of change. The MMN was recorded from healthy young adults for intensity decrements of 10, 20, 30, 40, and 50 dB. As the change increased, the MMN amplitude also increased first and thereafter diminished; thus, an inverted U-shaped relation was found between the MMN amplitude and the magnitude of change. These results, therefore, suggest a possible interplay between the energy of deviant stimulus and magnitude of change in the MMN elicitation.

Neural process underlying gap detection for spectrally rich and asymmetrical markers.

Processing of silent gaps of the order of milliseconds is crucial in speech perception. To investigate such process, we compared gap detection for spectrally symmetrical, slightly or widely asymmetrical markers, using the mismatch negativity (MMN), an index of preattentive change detection in the brain. The slightly asymmetrical markers declined the MMN amplitude alone, but the widely asymmetrical markers affected both the MMN amplitude and latency, suggesting that the influence of spectrally asymmetrical markers on gap detection is not uniform across different magnitude of asymmetries. In contrast to the prevailing view, the MMN obtained indicated that the effects of marker asymmetry took place as early as at preattentive stage.