Diagnosis and clinical course in mood disorders and depression subtypes

Beyond the monoaminergic hypothesis: agomelatine, a new antidepressant with an innovative mechanism of action

There are many potentials for the development of more effective, better tolerated, and more rapidly acting antidepressants. As there is large prevalence of circadian dysfunction in various affective disorders, including depression, one of the approaches is the development of antidepressant drugs with melatonergic agonist properties. Agomelatine, with its melatonergic agonistic (at both MT(1) an MT(2) receptors) and 5-HT(2C) antagonistic properties, represents a new concept for the treatment of depression. The antidepressant action of agomelatine has been initially demonstrated in animal models of depression, such as the forced swim - the learned helplessness - and the chronic mild stress paradigms. Subsequent studies demonstrated that the antidepressant activity of agomelatine does not solely depend on its agonistic action at melatonergic receptors, but also on its antagonistic activity at 5-HT(2C) receptors. Agomelatine also exhibits anxiolytic properties that bear a striking resemblance to those of selective 5-HT(2C) receptor antagonists. In patients with major depressive disorder, agomelatine had efficacy at least comparable to that seen with available antidepressants. Interestingly, agomelatine demonstrated antidepressant efficacy not only in patients with a moderate depressive episode but also in a more severe depressed subpopulation of patients. The treatment effect increased with the severity of the disease. Agomelatine also rapidly regulates the sleep-wake cycle without causing sedation and improves daytime condition. Agomelatine has an excellent safety profile, is weight neutral, does not affect sexual functioning and does not cause discontinuation syndrome. Collectively, its efficacy, together with its excellent tolerability, makes agomelatine an especially promising antidepressant for the near future.

Atypical depression, somatic depression and anxious depression in women: are they gender-preferred phenotypes?

BACKGROUND

Both depression and anxiety disorders affect women at rates significantly greater than men. Women also have a documented higher frequency of comorbid depression and anxiety disorders, and a three-fold higher prevalence of atypical depression.

HYPOTHESES

These gender differences are mainly due to specific depressive phenotypes including anxious depression and atypical depression. The prevalence of comorbid anxiety and depression strongly suggests overlap of pathophysiological mechanisms-which in women are also affected by fluctuations in gonadal hormones. Similar efficacy of serotonergic antidepressants as treatment for anxiety disorders as well as depressions further underscores the blurred boundaries between these two descriptive entities.

CONCLUSIONS

Symptoms of depression and anxiety may be a departure point for differential diagnosis in which dimensionally-based phenotypes substantiated by pathobiology would replace current descriptive entities. It is suggested that at least some biologically-based dysphorias may be specific to women, ensuing from the combination of specific vulnerabilities, and complex interactions between brain mechanisms and gonadal hormones.