Postpartum Depression Information

The diagnostic criteria for postpartum depression (PPD) are the same as that for major depression, except that to distinguish PPD from the baby (maternity) blues, the symptoms must be present past the second week postpartum.

Predictors of Postpartum Depression
While not all causes of PPD are known, several factors have been identified. Beck (2001) has conducted a meta-analysis of predictors of PPD. She found that the following 13 factors were significant predictors of PPD (effect size in parentheses -- larger values indicate larger effects):

1. Prenatal depression, i.e., during pregnancy (.44 to .46)
2. Low self esteem (.45 to.47)
3. Childcare stress (.45 to .46)
4. Prenatal anxiety (.41 to .45)
5. Life stress (.38 to .40)
6. Low social support (.36 to .41)
7. Poor marital relationship (.38 to .39)
8. History of previous depression (.38 to.39)
9. Infant temperament problems/colic (.33 to .34)
10. Maternity blues (.25 to .31)
11. Single parent (.21 to .35)
12. Low socioeconomic status (.19 to .22)
13. Unplanned/unwanted pregnancy (.14 to .17)

These factors are known to correlate with PPD. That means that, e.g., high levels of childcare stress are associated with high PPD levels, and low levels of childcare stress are associated with low levels of PPD. Some factors, like lack of social support, are known to cause postpartum depression. (The strong association of PPD with lack of social support has been confirmed by over 60 studies; see, e.g, the meta-analyses of Beck 1996a, and O’Hara and Swain 1996. The causal role of lack of social support in PPD is strongly suggested by, e.g., O'Hara 1985, Field et al. 1985; and Gotlib et al. 1991.)

Although profound hormonal changes after childbirth are often claimed to cause PPD, there is little evidence that variation in pregnancy hormone levels is correlated with variation in PPD levels: Studies that have examined pregnancy hormone levels and PPD have usually failed to find a relationship (see, e.g., Harris 1994; O'Hara 1995). Further, fathers, who are not undergoing profound hormonal changes, suffer PPD at relatively high rates. Finally, all mothers experience these hormonal changes, yet only about 10-15% suffer PPD. This does not mean, however, that hormones do not play a role in PPD. Block et al (2000), for example, found that, in women with a history of PPD , a hormone treatment simulating pregnancy and parturition caused these women to suffer mood symptoms. The same treatment, however, did not cause mood symptoms in women with no history of PPD. One interpretation of these results is that there is a subgroup of women who are vulnerable to hormone changes during pregnancy. Another interpretation is that simulating a pregnancy will trigger PPD in women who are vulnerable to PPD for any of the reasons indicated by Beck's meta-analysis (summarized above).

Profound lifestyle changes brought about by caring for the infant are also frequently claimed to cause PPD, but, again, there is little evidence for this hypothesis. Mothers who have had several previous children without suffering PPD can nonetheless suffer it with their latest child. Plus, most women experience profound lifestyle changes with their first pregnancy, yet most do not suffer PPD.

Postpartum Psychosis
In severe cases, postpartum psychosis (also known as puerperal psychosis) can develop, characterized by hallucinations and delusions. This happens in about 0.1 - 0.2% of all women after having given birth. In some cases, postpartum psychosis can develop independent of postpartum depression.

Sometimes a preexisting mental illness can be brought to the forefront through a postpartum depression.

An evolutionary psychological hypothesis for postpartum depression
Summary: Mothers with inadequate social support, an unhealthy child, a lack of resources (e.g., financial problems in contemporary societies), or other costly and stressful circumstances, have negative reactions towards the baby because these mothers would not have been able to successfully raise the child in ancestral-type conditions.

Evolutionary approaches to parental care (e.g., Trivers 1972) suggest that parents (human and non-human) will not automatically invest in all offspring, and will reduce or eliminate investment in their offspring when the costs outweigh the benefits. Reduced care, abandonment, and killing of offspring have been documented in a wide range of species. In many bird species, for example, both pre- and post-hatching abandonment of broods is common (e.g., Ackerman et al. 2003; Cezilly 1993; Gendron and Clark 2000).

Human infants require an extraordinary degree of parental care. Lack of support from fathers and/or other family member will increase the costs born by mothers, whereas infant health problems will reduce the evolutionary benefits to be gained. If ancestral mothers did not receive enough support from fathers or other family members, they may not have been able to "afford" raising the new infant without harming any existing children, or damaging their own health (nursing depletes mothers' nutritional stores, placing the health of poorly nourished women in jeopardy).

For mothers suffering inadequate social support or other costly and stressful circumstances, negative emotions directed towards a new infant could serve an important evolved function by causing the mother to reduce her investment in the infant, thereby reducing her costs.

Numerous studies support the correlation between postpartum depression and lack of social support or other childcare stressors. Mothers with postpartum depression also reduce their investment in their new offspring. They commonly have thoughts of harming their children, exhibit fewer positive emotions and more negative emotions toward them, are less responsive and less sensitive to infant cues, less emotionally available, have a less successful maternal role attainment, and have infants that are less securely attached (Beck 1995, 1996b; Cohn et al. 1990, 1991; Field et al. 1985; Fowles 1996; Hoffman and Drotar 1991; Jennings et al. 1999; Murray 1991; Murray and Cooper 1996). In other words, most mothers with PPD are suffering some kind of cost, like inadequate social support, and consequently are mothering less. PPD may be an adaptation that, via negative emotions, informs mothers that they cannot "afford" the new baby and that motivates them to reduce or eliminate investment in offspring. It may also help them negotiate greater levels of investment from others.

If this view is correct (and it is far from proven), mothers with PPD do not have a mental illness, they need more social support, more resources, etc. Treatment for PPD should therefore focus on helping mothers get what they need. For more on this hypothesis, see Hagen 1999 and Hagen and Barrett, n.d..

Andrea Yates Case
After the National Organization for Women (NOW) insisted that Andrea Yates had postpartum depression, the Individualist Feminists of Ifeminist.com pointed out that postpartum depression is quite common and most sufferers do not murder their children. In fact, Yates suffered from postpartum psychosis. After Ifeminist.com pointed out that this stigmatized a large number of mothers and made them less likely to seek professional help, NOW removed their claims from their official website. Some believe that Yates' fundamentalist church bears some responsibility for the murder, as the church allegedly urged her to ignore her psychiatrist's orders. Yates methodically drowned her children in a bathtub in her Clear Lake City, Houston, Texas house on June 20, 2001.

References
Ackerman, J. T., Eadie, J. M., Yarris, G. S., Loughman, D. L., & Mclandress R. M. (2003) Cues for investment: nest desertion in response to partial clutch depredation in dabbling ducks. Animal Behaviour, 66, 871–883.

Beck, C.T. The effects of postpartum depression on maternal-infant interaction: a meta-analysis. Nursing Research 44:298–304, 1995.

Beck, C.T. A meta-analysis of predictions of postpartam depression. Nursing Research 45:297–303, 1996a.

Beck, C.T. A meta-analysis of the relationship between postpartum depression and infant temperament. Nursing Research 45:225–230, 1996b.

Bect, C.T. (2001) Predictors of Postpartum Depression: An Update. Nursing Research, 50, 275-285.

Cezilly, F. (1993) Nest desertion in the greater flamingo, Phoenicopterus ruber roseus. Animal Behaviour, 45, 1038-1040.

Cohn, J.F., Campbell, S.B., Matias, R., and Hopkins, J. Face-to-face interactions of postpartum depressed and nondepressed mother-infant pairs at 2 months. Developmental Psychology 26:15–23, 1990.

Cohn, J.F., Campbell, S.B., and Ross, S. Infant response in the still-face paradigm at 6 months predicts avoidant and secure attachment at 12 months. Special Issue: Attachment and developmental psychopathology. Development and Psychopathology 3:367–376, 1991.

Field, T., Sandburg, S., Garcia, R., Vega-Lahr, N., Goldstein, S., and Guy, L. Pregnancy problems, postpartum depression, and early mother-infant interactions. Developmental Psychology 21:1152– 1156, 1985.

Fowles, E.R. Relationships among prenatal maternal attachment, presence of postnatal depressive symptoms, and maternal role attainment. Journal of the Society of Pediatric Nurses 1:75–82, 1996.

Gendron, M. & Clark, R. G. (2000) Factors affecting brood abandonment in gadwalls (Anas strepera). Canadian Journal of Zoology, 78, 327–331.

Gotlib, I.H., Whiffen, V.E., Wallace, P.M., and Mount, J.H. Prospective investigation of postpartum depression: factors involved in onset and recovery. Journal of Abnormal Psychology 100:122– 132, 1991.

Harris, B. Biological and hormonal aspects of postpartum depressed mood: working towards strategies for prophylaxis and treatment. Special Issue: Depression. British Journal of Psychiatry 164:288–292, 1994.

Hoffman, Y., and Drotar, D. The impact of postpartum depressed mood on mother-infant interaction: like mother like baby? Infant Mental Health Journal 12:65–80, 1991.

Jennings, K.D., Ross, S., Popper, S., and Elmore, M. Thoughts of harming infants in depressed and nondepressed mothers. Journal of Affective Disorders, 1999.

Murray, L. Intersubjectivity, object relations theory, and empirical evidence from mother-infant interactions. Special Issue: The effects of relationships on relationships. Infant Mental Health Journal 12:219–232, 1991.

Murray, L., and Cooper, P.J. The impact of postpartum depression on child development. International Review of Psychiatry 8:55–63, 1996.

O’Hara, M.W. Depression and marital adjustment during pregnancy and after delivery. American Journal of Family Therapy 13:49–55, 1985.

O’Hara, M.W. Postpartum Depression: Causes and Consequences. New York: Springer-Verlag, 1995.

O’Hara, M.W., and Swain A.M. Rates and risk of postpartum depression – A meta-analysis. International Review of Psychiatry 8:37–54, 1996.

Trivers, R. L. (1972) Parental investment and sexual selection. In B. Campbell (Ed.), Sexual Selection and the Descent of Man (pp. 136-179). London: Heinemann.