The few studies on the topic showed that high pretreatment δ activity5,21 and redistribution of δ activity to the earlier part of the night may predict ultimate clinical response. 22 For instance, we have shown a clear relationship between baseline sleep EEG spectral density values and clinical response (Selleck GDC-0068 Figure 1). Another study

has shown that different forms of δ activity can distinguish between acute depression and the Inhibitors,research,lifescience,medical risk of recurrence in previously recovered patients. On the basis of fundamental studies23 showing that the δ bandwidth (thought to be generated in thalamic nuclei) also contains slow oscillations (0.5-1 Hz) originating in the cortex, Buysse et al24 demonstrated that high δ activity (2-3 Hz) was more related to the acute depressive state, while the

lower frequencies (0.5-1 Hz) were linked to risk of recurrence. Other research efforts focused on the significance of a frequency during REM sleep. In a topographic study, we found that Inhibitors,research,lifescience,medical REM α power spectra are reduced after antidepressant administration in healthy volunteers (Figure 2),25 a finding that needs to be extended to depressed patients Inhibitors,research,lifescience,medical in order to assess its potential predictive value. Figure 1. Electroencephalography (EEG) spectral analysis baseline parameters in responders (gray) and nonresponders (blue). Figure 2. Effects of fluoxetine 20 mg on topographical alpha activity distribution during rapid eye movement (REM) sleep. F4C4, frontocentral derivation; C4P4, centroparietal

derivation; P402, parieto-occipital derivation. Another promising direction for future research is the study of change in dynamic relationships, or coherence, between frequency ranges.26 Coherence evaluates the strength of covariation between two frequency Inhibitors,research,lifescience,medical rhythms: if two frequencies have high coherence, they are likely to be controlled by the same or similar timing mechanism. Inhibitors,research,lifescience,medical In this context, Armitage et al27 reported that β and δ rhythms were less coherent in depressive patients than in healthy controls, and Röschke et al28 suggested that 4 weeks’ administration of paroxetine in healthy volunteers significantly increased coherence between β and δ frequencies. Conclusion Clinical research on the influence of antidepressant drugs on sleep microarchitecture will become increasingly important for interpreting the effects of antidepressants on sleep physiology and for the development Cediranib (AZD2171) of new antidepressant therapies. In this regard, spectral EEG sleep profiles represent a promising tool for the prediction of clinical response to antidepressant treatment.
Contrary to somatic medicine, psychiatric symptomatology – with the possible exception of behavioral symptoms and social consequences – is not readily described by objective measures. Rather, psychiatric symptoms are produced by the patient’s perception and subjective experience.