Associations between brain-derived neurotrophic factor plasma levels and severity of the illness, recurrence and symptoms in depressed patients.

BACKGROUND: There is increasing evidence that the brain-derived neurotrophic factor (BDNF) is involved in the pathophysiology of mood disorders and that its peripheral levels represent a reliable mirror of its concentration in the brain. The aim of the present study was to measure BDNF plasma levels in patients affected by major depression and to explore the possible relationship between the biological parameter and characteristics of the illness. METHOD: BDNF plasma levels were evaluated in 30 inpatients suffering from major depression, according to DSM-IV criteria, by means of a commonly employed ELISA method. The clinical characteristics were assessed by the Hamilton Rating Scale for Depression (HRSD) and the Clinical Global Impression Scale. RESULTS: BDNF plasma levels were significantly lower in the patients with the severest illness compared with the others, and the same was true for patients with dissociative symptoms, severe sleep disturbance and recurrent depression. A significant and negative correlation was observed between the biological parameter and the retardation factor score of the HRSD. CONCLUSION: These findings suggest that low BDNF levels are related to both recurrence and severity of depression, as well as to symptoms typical of dysfunctions of the hypothalamic-pituitary-adrenal axis.

Plasma Brain-Derived Neurotrophic Factor in treatment-resistant depressed patients receiving electroconvulsive therapy.

There is an increasing evidence that the Brain-Derived Neurotrophic Factor (BDNF) could be involved in the mode of action of antidepressants and, perhaps, of ECT. This study aimed to investigate whether the clinical course of medication-resistant depressed patients following a course of ECT might be associated with changes of plasma BDNF concentrations. Our findings showed that at T0 (baseline) plasma BDNF levels of patients were significantly lower than those of control subjects, and that at T2 (after ECT) were significantly increased in parallel with the decrease of the Hamilton Rating Scale for Depression (HRSD) total score. However, only remitter patients who showed higher baseline BDNF levels than non-remitters reached normalized BDNF levels after ECT. These findings would suggest the potential usefulness of baseline plasma BDNF levels as predictors of response to ECT in treatment-resistant depressed patients.

Diurnal variation of plasma brain-derived neurotrophic factor (BDNF) in humans: an analysis of sex differences.

Scant information is available on the diurnal variation of peripheral neurotrophic factors, including brain-derived neurotrophic factor (BDNF), in human beings. We explored plasma and serum BDNF levels at three different clock times in a study of 28 healthy subjects of both sexes. Statistically significant diurnal variation in plasma BDNF level was detected in men, with the peak at 08:00 h and nadir at 22:00 h. At this time, the plasma BDNF concentration of men was significantly lower than that of women (p=.02). However, no diurnal variation was found either in plasma BDNF of women, in either the follicular or luteal phases of the menstrual cycle, or in serum BDNF level in both men and women. These findings support the concept of rhythmic variation in plasma BDNF regulation that seems to be sex-related.

Plasma and serum brain-derived neurotrophic factor (BDNF) in depressed patients during 1 year of antidepressant treatments.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) has been hypothesized to be involved in the neurobiology of major depression. The aim of this study was to assess the possible relationships between depressive symptoms and serum and/or plasma BDNF levels during 1 year of antidepressant treatment. METHODS: Plasma and serum BDNF levels were assayed in 15 drug-free depressed patients and in 15 healthy control subjects at baseline and the 1st, 3rd, 6th and 12th month of antidepressant treatment. RESULTS: At baseline, patients' serum and plasma BDNF levels were significantly lower (p<.001 and p=.004, respectively) than those found in healthy control subjects. However, while from the 1st month of treatment patients' plasma BDNF levels did not differ significantly from those observed in healthy control subjects, serum BDNF levels in patients remained significantly lower at all times. LIMITATIONS: The main limitations of the current study are represented by the small sample size and the high discontinuation rate. CONCLUSIONS: Untreated depressed patients showed reduced baseline serum and plasma BDNF levels, as compared with control subjects. The clinical improvement paralleled the normalization of plasma BDNF after 1 month of treatment, while, at every assessment time, patients' serum BDNF levels were lower than those of control subjects. This would suggest that serum BDNF might represent a non-specific trait marker of depression.

Health-related quality of life and functioning in remitted bipolar I outpatients.

The aim of this study was to characterize the health-related quality of life (HR-QOL) and functioning in 90 bipolar I remitted outpatients. According to Diagnostic and Statistical Manual of Mental Disorders IV remission specifiers, patients were categorized into 4 groups: group 1, fully remitted; group 2, less than 2 months remitted; group 3, with persisting manic symptoms; group 4, with persisting depressive symptoms. The severity of psychopathology was evaluated by using the Bech-Rafaelsen Mania-Melancholia Scale. The HR-QOL, functioning, and insight were assessed via the medical outcomes study 36-item short form, the global assessment of functioning scale, and the scale to assess unawareness of mental disorder, respectively. Fully remitted patients reported the highest scores in almost all domains of medical outcomes study 36-item short form, and had significantly higher scores on physical functioning, general health, social functioning, and mental health compared to patients with persisting depressive symptoms. Furthermore, patients with persisting manic symptoms reported significantly higher scores on general health, vitality and mental health than the group with persisting depressive symptoms. In contrast, the global assessment of functioning scale score differed among the 4 groups, with fully remitted patients reporting higher, although not statistically significant, scores than the other groups. Our data suggest that the persistence of depressive or manic symptoms seem to affect self-report measures of HR-QOL. An affectively biased cognition may explain the gap between patient's perception of functioning and estimated functional adjustment, as assessed by clinicians.