Abnormal platelet 5-hydroxytryptamine uptake and imipramine binding in postnatal dysphoria

Biological aspects of postpartum depression

In comparison with the vast epidemiological literature on postpartum depression (PPD), relatively few studies have examined the biological aspects of the disorder. However, research into the biological mechanisms of PPD is a challenging task, as normal pregnancy and the postpartum period cause adaptive endocrine changes, which would otherwise be considered pathological in nonpregnant women. This review focuses on the adaptive changes of childbearing and nursing, which ultimately may put women at increased risk of PPD. In light of the normal physiology, the authors also attempt to describe the current evidence of the biological changes associated with the development of depression in the postpartum period, including ovarian steroids, the hypothalamic-pituitary-adrenal axis, the serotonergic neurotransmitter system, the thyroid system and inflammatory markers. In addition, current knowledge on candidate genes associated with PPD is reviewed.

Sequential serotonin and noradrenalin associated processes involved in postpartum blues

OBJECTIVE

We investigated whether postpartum blues was related to changes in parameters of noradrenergic and serotonergic functioning.

METHODS

From 26 healthy pregnant women blood was collected at the end of pregnancy and 5 days and 6 weeks postpartum. Serotonergic parameters were: platelet serotonin content; paroxetine binding to platelet membranes as an index of serotonin transporter activity; the serotonin precursor tryptophan in proportion to the large neutral amino acids, as an estimate of its cerebral influx. Noradrenergic indices were the noradrenaline precursor tyrosine and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG). The Kennerly and Gath blues questionnaire was applied at day five postpartum.

RESULTS

The incidence of postpartum blues was 30%. The tryptophan ratio and serotonin content of platelets were decreased (p<0.01) at day five postpartum in all women. Bmax paroxetine at day five was correlated with blues score (beta=0.460; p=0.031). MHPG levels at 6 weeks were increased in women with blues (p<0.001). In a regression model MHPG at 6 weeks was related to blues score (beta=0.477; p=0.002) and MHPG at day five (beta=0.550; p=0.001), explaining >50% of the variation (R2=0.588; p<0.001).

CONCLUSIONS

A decreased serotonergic activity was found at the fifth day postpartum in all subjects. Increased SERT activity, reflected by higher paroxetine binding to platelets might be involved in the onset of blues. The elevated MHPG levels in women with blues are compatible with a higher stress sensitivity, or a decreased stress coping in those and is suggested to be involved with the onset of depression.

Serotonergic candidate genes and puerperal psychosis: an association study

BACKGROUND

Altered serotonergic function is implicated in the aetiology and pathogenesis of a host of psychiatric disorders, and structural variations/polymorphisms in genes encoding the serotonin transporter and various serotonin receptor subtypes are attractive candidates to investigate the biological component underlying these disorders. Specific phenotypic subtypes, that perhaps represent homogeneous forms of the disorder, may increase the power to detect genes in complex diseases.

OBJECTIVE

We investigated regulatory and functional polymorphic DNA markers of serotonergic candidate genes using a case-control approach in puerperal psychosis and bipolar affective disorder probands.

METHODS

We genotyped 320 female participants (104 puerperal psychosis probands, 102 bipolar disorder participants and 114 controls) at the serotonin transporter SERT (5-HTT) 5-HTTVNTR and 5-HTTLPR locus; serotonin receptor 2A (5-HT2A)-T102C and His452Tyr loci, the serotonin receptor 2C (5-HT2C)-Cys23Ser locus, and seven unrelated Alu polymorphic markers.

RESULTS

We observed an association of the puerperal psychosis phenotype with the allele 10 of 5-HTTVNTR of SERT (P=0.004) and a modest association with the genotypic frequencies of the 5-HTTLPR (P=0.036). A nominal P value of 0.006 was observed with the S-10 haplotype in the PP group as compared with bipolar affective disorder probands. Significant association was observed with bipolar affective disorder phenotype with Tyr allele of the 5-HT2A His452Tyr gene polymorphism (P=0.00043) even after a conservative multiple test correction. No association was observed, however, with the 5-HT2A T102C locus, and the distribution of the other seven Alu markers did not differ between the groups.

CONCLUSION

The association between polymorphisms in serotonergic genes (SERT and 5-HT2A, 5-HT2C) suggests that these genetic factors can modulate vulnerability to puerperal psychosis in female bipolar participants.

Alterations in platelet serotonin transporter binding in women with postpartum onset major depression

There is considerable debate as to whether postpartum depression (PPD) is biologically distinct from other depressive syndromes. Although abnormalities in serotonergic neural systems have repeatedly been reported in depression, few such studies have been conducted in PPD. In the present study, platelet serotonin transporter (SERT) binding was assessed using [(3)H]paroxetine in 14 depressed pregnant women, 31 normal healthy pregnant women, 39 depressed postpartum women, and 27 normal healthy postpartum women; all of the subjects were drug-free. Significant differences were detected among the 4 groups with respect to the dissociation constant (Kd) of platelet binding sites for [(3)H]paroxetine with the highest Kd values among those with PPD. The density (Bmax) of platelet binding sites for [(3)H]paroxetine did not differ between the study groups. These data suggest that PPD may be associated with unique alterations in serotonergic function that are specific to the puerperium.

Endocrine factors in the etiology of postpartum depression

This article reviews the literature regarding endocrine factors postulated or presumed to be relevant in postpartum depression (PPD), a condition affecting at least 10% of childbearing women. The phenomenology and epidemiology of PPD are also described. Data suggest that parturition-related endocrine changes are causally implicated in PPD in a vulnerable subgroup of women. More specifically, studies by our group and others suggest a role for changes in estradiol and progesterone in precipitating mood symptoms among women with PPD. The mechanisms underlying such differential sensitivities remain undetermined. Future directions for research are explored.

Etiology and treatment of postpartum depression

This article reviews the risk factors, pathogenesis, treatment, and prevention of postpartum depression. Postpartum depression is common and occurs in up to 18% of newly delivered mothers. Though the hormonal changes occurring after childbirth are believed to play a role in postpartum depression, no hormonal etiology has been identified. Estrogen appears somewhat helpful for postpartum depression, but its use is limited by problematic medical sequelae. Several antidepressants are effective for postpartum depression and appear safe for use by breastfeeding women. Psychosocial interventions and cultural rituals, which may prevent or ameliorate postpartum depression, have also been employed.

Gonadal steroids in the treatment of mood disorders

Increased interest in the complex interplay between gonadal steroids and neurotransmitter systems involved in mood has led investigators to question the role of gonadal steroids in the treatment of affective disorders, especially in women.

OBJECTIVES

The purpose of this article is to provide a rationale for using gonadal hormones in the treatment of depression in women.

METHODS

The literature is reviewed regarding 1) sex-specific phenomenologic and epidemiologic differences in the manifestation of psychiatric illness, 2) sex-specific differences in the therapeutic and adverse effects of psychotropic medications, 3) the complex interplay between gonadal steroids and neurotransmitter systems implicated in psychiatric disorders, and 4) the growing literature regarding the use of estrogen and progesterone in the treatment of mood disorders in women and androgens in the treatment of depression and sexual dysfunction in both men and women.

RESULTS

Findings from pharmacologic trials of estrogen and androgens are encouraging, albeit mixed, in the treatment of mood disorders and decreased libido in women, respectively. Controlled studies have failed to confirm early open-label reports of the effectiveness of progesterone in the treatment of premenstrual syndrome.

CONCLUSIONS

Pending replication, estrogen may become an important pharmacologic agent in the treatment of postnatal and perimenopausal depression, whereas androgens have been shown to improve libido in postmenopausal women and hypogonadal men. Progesterone cannot be recommended as a treatment for premenstrual syndrome or postnatal depression.

Women at risk for postpartum-onset major depression

There is considerable evidence that the childbearing years represent a time when women are highly vulnerable to developing mood disorders. Prospective, cross-sectional, and retrospective studies have demonstrated that more than 10% of new adult mothers will experience a major depressive episode during the first postpartum year. Changes in the health care delivery system will result in increased pressure on the obstetrician/gynecologist to identify and treat women with postpartum-onset depression. Despite shortcomings in the available literature, prospective studies have identified risk factors for developing postpartum depression. Furthermore, the clear overlap between the normal sequelae of childbirth and the symptoms of major depression, including alterations in sleep, energy, libido, appetite, and body weight, underscores the need to develop guidelines for early identification. We furnish a brief overview of postpartum mood disorders with a primary focus on the antenatal and postnatal risk factors for developing postpartum depression. Based on the extent literature and our clinical experience, a set of recommendations for early identification and treatment is provided.

Do biochemical factors play a part in postnatal depression?

1. There are major changes in progesterone, oestrogen, cortisol and beta-endorphin level associated with parturition, and as all these can be psychoactive it is likely that they contribute to the mood changes that can occur at this time. However evidence for their involvement is, at present, indirect. 2. Postnatal depression itself appears to be a heterogeneous condition with different times of onset, and it is probable that various biological and social factors play a role to a differing degree in different individuals. 3. About half of postnatal depression appears to arise in the first two weeks after childbirth. Some cases follow a period of early euphoria. 4. A different subgroup is associated with thyroid dysfunction, which peaks two to five months postpartum. 5. The tyramine test does not predict vulnerability to postnatal depression. 6. It is suggested that in future research the time course of onset of the depression, and the nature of the mood changes that occur in the first postpartum week, are investigated as possibly relevant variables.