Biomedical subjects

Heikki Rytsälä

Publications and source records attributed to Heikki Rytsälä.

7 recordsLinked to original sources

PubMed2007

Impaired functional connectivity at EEG alpha and theta frequency bands in major depression.

Recent reports on functional brain imaging in major depression have lead to an assumption that observed psychopathology might be related to an altered brain functional connectivity. Our hypothesis was that an increase in brain functional connectivity occurs in major depression. As a measure of functional connectivity, the electroencephalogram (EEG) structural synchrony approach was used in 12 medication-free depressive outpatients and 10 control subjects. Differences in the number and strength of structurally synchronized EEG patterns were compared between groups. In depressive patients the number and strength of short cortex functional connections were significantly larger for the left than for the right hemisphere, while the number and strength of long functional connections were significantly larger for the right than for the left hemisphere. Some of the functional connections were positively correlated with the severity of depression, thus being predictive. These were short-range anterior, posterior, and left hemisphere functional connections for the alpha frequency band and short-range anterior functional connections for the theta frequency band. The topology of the most representative functional connections among all patients with major depression indicated that the right anterior and left posterior brain parts may discriminate depressive patients from healthy controls. The obtained data support our hypothesis that there is an increase in brain functional connectivity in major depression. This finding was interpreted within the semantic framework, where different specialization of left (monosemantic context) and right (polysemantic context) hemispheres is functionally insufficient in patients with depression.

Adult↗

PubMed2006

Composition of brain oscillations in ongoing EEG during major depression disorder.

In the present study, we examined the composition of electroencephalographic (EEG) brain oscillations in 12 unmedicated major depressive outpatients and 10 healthy subjects during resting conditions (closed eyes). The exact composition of brain oscillations was assessed by the probability-classification analysis of short-term EEG spectral patterns. In contrast to previous studies of depression, the current study found that major depression affects brain activity in nearly the whole cortex and manifests itself in considerable reorganization of the composition of brain oscillations in a broad frequency range: 0.5-30 Hz. At the same time, the magnitude of the effect of depression was maximal in the posterior cortex of the brain. Interhemisphere asymmetry during major depression was also observed in the whole cortex with right hyperactivity in frontal, parietal and occipital brain areas. It is suggested that depressive brain is manifested in the superposition of distributed multiple oscillations. Our findings provide new insight on the relationship between major depressive disorder and cortical oscillatory activity.

Adult↗

PubMed2006

Decline in suicidal ideation among patients with MDD is preceded by decline in depression and hopelessness.

BACKGROUND: Suicidal ideation is likely to represent a phase preceding suicidal acts among most suicidal patients with major depressive disorder (MDD). Factors predicting reversal of the suicidal process are unknown. Our aim was to test the hypothesis that a decline in suicidal ideation is preceded by a decline in hopelessness among patients with MDD. METHOD: Of the 269 Vantaa Depression Study patients with DSM-IV MDD, 103 patients scored > or = 6 points at baseline on the Scale for Suicidal Ideation (SSI). Seventy of these patients were followed-up weekly either until they scored zero points on the SSI, or up to 26 weeks. RESULTS: The median duration for a decline of suicidal ideation to zero was 2.2 months after baseline. The level of baseline suicidal ideation, depressive symptoms, and the presence of any personality disorder predicted duration of suicidal ideation. A decline in both depression (BDI) and hopelessness (HS) independently predicted a decline in suicidal ideation. LIMITATIONS: Due to study design, we do not know if suicidal ideation relapsed after the first time the patient reached zero score in the SSI. CONCLUSIONS: Among patients with major depressive disorder having suicidal ideation, the decline in suicidal ideation is independently predicted by preceding declines in the levels of both depressive symptoms as well as hopelessness. The findings are consistent with possible causal roles of declines in depression and hopelessness in reversing the suicidal process.

Affect↗

PubMed2006

The influence of adversity and perceived social support on the outcome of major depressive disorder in subjects with different levels of depressive symptoms.

BACKGROUND: Adverse life events and social support may influence the outcome of major depressive disorder (MDD). We hypothesized that outcome would depend on the level of depressive symptoms present at the outset, with those in partial remission being particularly vulnerable. METHOD: In the Vantaa Depression Study (VDS), patients with DSM-IV MDD were interviewed at baseline, and at 6 and 18 months. Life events were investigated with the Interview for Recent Life Events (IRLE) and social support with the Interview Measure of Social Relationships (IMSR) and the Perceived Social Support Scale - Revised (PSSS-R). The patients were divided into three subgroups at 6 months, those in full remission (n = 68), partial remission (n = 75) or major depressive episode (MDE) (n = 50). The influence of social support and negative life events during the next 12 months on the level of depressive symptoms, measured by the Hamilton Rating Scale for Depression (HAMD), was investigated at endpoint. RESULTS: The severity of life events and perceived social support influenced the outcome of depression overall, even after adjusting for baseline level of depression and neuroticism. In the full remission subgroup, both severity of life events and subjective social support significantly predicted outcome. However, in the partial remission group, only the severity of events, and in the MDE group, the level of social support were significant predictors. CONCLUSIONS: Adverse life events and/or poor perceived social support influence the medium-term outcome of all psychiatric patients with MDD. These factors appear to have the strongest predictive value in the subgroup of patients currently in full remission.

Adult↗

PubMed2006

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Journal Article↗

PubMed2005

Breakdown of long-range temporal correlations in theta oscillations in patients with major depressive disorder.

Neuroimaging has revealed robust large-scale patterns of high neuronal activity in the human brain in the classical eyes-closed wakeful rest condition, pointing to the presence of a baseline of sustained endogenous processing in the absence of stimulus-driven neuronal activity. This baseline state has been shown to differ in major depressive disorder. More recently, several studies have documented that despite having a complex temporal structure, baseline oscillatory activity is characterized by persistent autocorrelations for tens of seconds that are highly replicable within and across subjects. The functional significance of these long-range temporal correlations has remained unknown. We recorded neuromagnetic activity in patients with a major depressive disorder and in healthy control subjects during eyes-closed wakeful rest and quantified the long-range temporal correlations in the amplitude fluctuations of different frequency bands. We found that temporal correlations in the theta-frequency band (3-7 Hz) were almost absent in the 5-100 s time range in the patients but prominent in the control subjects. The magnitude of temporal correlations over the left temporocentral region predicted the severity of depression in the patients. These data indicate that long-range temporal correlations in theta oscillations are a salient characteristic of the healthy human brain and may have diagnostic potential in psychiatric disorders. We propose a link between the abnormal temporal structure of theta oscillations in the depressive patients and the systems-level impairments of limbic-cortical networks that have been identified in recent anatomical and functional studies of patients with major depressive disorder.

Adult↗

PubMed2004

Co-morbidity and stability of melancholic features in DSM-IV major depressive disorder.

BACKGROUND: The descriptive validity of the melancholic features specifier of the DSM-IV major depressive disorder (MDD) is uncertain. Little is known about its relationship to psychiatric co-morbidity, stability across episodes, or strength in predicting course of illness. METHOD: The Vantaa Depression Study (VDS) is a prospective, naturalistic cohort study of 269 patients with a new episode of DSM-IV MDD who were interviewed with SCAN and SCID-II between 1 February 1997 and 31 May 1998, and again at 6 and 18 months. Ninety-seven (36%) MDD patients met DSM-IV criteria for the melancholic features specifier, and were contrasted with 172 (64 %) subjects with a non-melancholic MDD. The duration of the index episode was examined using a life chart. RESULTS: We found no difference in rates of any current co-morbid Axis I or II disorders between melancholic and non-melancholic depressed patients. Of those who had melancholic features at the index episode and subsequent episodes during the 18-month follow-up, only 22 % (5/23) presented melancholic features during the latter. The non-melancholic subtype switched to melancholic in 25 % (8/32) of cases. Differences in the course of melancholic and non-melancholic depression were very minor. CONCLUSIONS: The descriptive validity of the DSM-IV melancholic features specifier may be questionable in MDD. There appear to be no major differences in current co-morbidity, or course of depression between melancholic and non-melancholic patients. The consistency of DSM-IV melancholic features across episodes appears weak.

Adult↗