Gene-Environment Interactions in Major Depressive Disorder.

Gene-environment interactions in major depressive disorder.

Can J Psychiatry. 2013 Feb; 58(2): 76-83
Klengel T, Binder EB

Family, twin, and epidemiologic studies have suggested that both genes and environment are important risk factors for the development of major depressive disorder (MDD). In the absence of consistent and strong main genetic effects, numerous studies have supported gene-environment interactions in this disorder. While the impact of negative environmental factors, such as early life stress, traumatic experiences, and negative life events have been established as risk factors, they are not sufficient to predict MDD. This article will review evidence suggesting that genetic variants moderate the effects of adversities on the development of MDD, with a focus on the importance of careful characterization of the stressful life events as well as systemic and molecular mechanisms that potentially mediate these gene-environment interactions. HubMed – depression


Depressive-like behaviour induced by an intracerebroventricular injection of streptozotocin in mice: the protective effect of fluoxetine, antitumour necrosis factor-? and thalidomide therapies.

Behav Pharmacol. 2013 Feb 24;
Souza LC, Filho CB, Fabbro LD, de Gomes MG, Goes AT, Jesse CR

Information on the effect of an intracerebroventricular (i.c.v.) injection of streptozotocin (STZ) on noncognitive behaviour in rodents such as depression states is scarce. Thus, the aim of this study was to examine the depressive-like effect of STZ injected by the i.c.v. route in mice and the potential protective effect of fluoxetine, antitumour necrosis factor-? (anti-TNF-?) and thalidomide. Our results indicated that a single injection of STZ (0.1 mg/site) promoted depressive-like behaviour in the tail suspension and sucrose preference tests without altering either locomotor activity or plasma glucose levels. We also showed that STZ increased TNF-? levels in the hippocampus of mice. Fluoxetine (32 mg/kg, intraperitoneally. 30 min before STZ injection), and the anti-TNF-? antibody (0.1 pg/site, i.c.v.) and thalidomide (3 mg/kg, subcutaneously), coadministered with STZ, prevented these effects. This is the first study to report depressive-like effects of STZ using the i.c.v. route in mice. We concluded that fluoxetine, anti-TNF-? antibody and thalidomide were effective in preventing depressive-like behaviour and the increase in TNF-? levels in the hippocampus of mice induced by an i.c.v. injection of STZ, reinforcing the involvement of TNF-? in the pathophysiology of depression. This model and the mechanisms studied may contribute towards the development of new antidepressant drugs and enhance the options for studying depression. HubMed – depression


Association between cortisol awakening response and memory function in major depression.

Psychol Med. 2013 Feb 27; 1-9
Hinkelmann K, Muhtz C, Dettenborn L, Agorastos A, Moritz S, Wingenfeld K, Spitzer C, Gold SM, Wiedemann K, Otte C

BACKGROUND: While impaired memory and altered cortisol secretion are characteristic features of major depression, much less is known regarding the impact of antidepressant medication. We examined whether the cortisol awakening response (CAR) is increased in depressed patients with and without medication compared with healthy controls (HC) and whether CAR is associated with memory function in each group. Method We examined 21 patients with major depression without medication, 20 depressed patients on antidepressant treatment, and 41 age-, sex- and education-matched healthy subjects. We tested verbal (Auditory Verbal Learning Task) and visuospatial (Rey figure) memory and measured CAR on two consecutive days. RESULTS: Patient groups did not differ in severity of depression. We found a significant effect of group (p = 0.03) for CAR. Unmedicated patients exhibited a greater CAR compared with medicated patients (p = 0.04) with no differences between patient groups and HC. We found a significant effect of group for verbal (p = 0.03) and non-verbal memory (p = 0.04). Unmedicated patients performed worse compared with medicated patients and HC in both memory domains. Medicated patients and HC did not differ. Regression analyses revealed a negative association between CAR and memory function in depressed patients, but not in HC. CONCLUSIONS: While in unmedicated depressed patients the magnitude of CAR is associated with impaired memory, medicated patients showed a smaller CAR and unimpaired cognitive function compared with HC. Our findings are compatible with the idea that antidepressants reduce CAR and partially restore memory function even if depressive psychopathology is still present. HubMed – depression