The Effects of Sleep Loss on the Risk for Postpartum Psychosis in Bipolar Disorder

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Women with bipolar disorder are at high risk for postpartum episodes.
Women with bipolar disorder are at high risk for postpartum episodes.

The perinatal period is associated with increased vulnerability to new-onset severe mental illness. Postpartum psychosis, for example, affects an estimated 1 in 1000 parous women in the general population and 20% to 30% of those with bipolar disorder.1-4 Research investigating the etiology of postpartum psychosis has identified immune dysregulation, genetic factors, and primiparity as potential factors.5

According to research published in January 2018 in the Journal of Affective Disorders,5 another factor warranting further examination is sleep loss, which has been shown to precede manic episodes in a range of studies.6-8 Other research has found that sleep deprivation has antidepressant effects, suggesting it may also have mania-inducing effects.9

Although evidence indicates a greater vulnerability to the negative effects of sleep loss in individuals with psychiatric disorders, there is also variation in response, as some patients with bipolar disorder report sleep loss as a trigger for mania, whereas others do not. In research that appeared in the September 2017 issue of the British Journal of Psychiatry, manic episodes triggered by sleep loss were associated with female sex (odds ratio [OR], 1.43; 95% CI, 1.17-1.75; P <.001) and bipolar I disorder (OR, 2.81; 95% CI, 2.26-3.50; P <.001), in particular.6

In the 2018 study, the researchers hypothesized that those who do experience sleep loss as a trigger for mania would also have a greater likelihood of experiencing postpartum psychosis.5 The sample included 870 parous women who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for bipolar I disorder, as assessed via clinician interview and review of case notes. The study focused on episodes of postpartum psychosis that occurred within 6 weeks of delivery, as this is the period in which most episodes have been found to occur.

The results showed that 23.5% of participants had experienced an episode of postpartum psychosis.5 As expected, those who reported mania triggered by sleep loss had greater odds of experiencing postpartum psychosis compared with those who did not report sleep loss as a trigger for mania (OR, 2.09; 95% CI, 1.47-2.97, P <.001), even when controlling for potential confounding variables. No significant association was observed between depression triggered by sleep loss and postpartum psychosis (P =.526).

These findings indicate that a "vulnerability to the mania-inducing qualities of sleep loss increases the risk of experiencing [postpartum psychosis], and is consistent with previous research suggesting that [postpartum psychosis] is frequently a manifestation of manic or mixed episodes triggered by childbirth," the authors concluded.5 "Importantly, our results suggest that women with [bipolar disorder-I] who report manic episodes triggered by sleep loss could be more vulnerable to developing [postpartum psychosis]," although additional studies on the topic are needed.5

Psychiatry Advisor interviewed study coauthor Ian Jones, MRCPsych, PhD, professor of psychiatry and director of the National Centre for Mental Health at Cardiff University in the United Kingdom, to further discuss these results and their clinical implications.

Psychiatry Advisor: Regarding your findings, what are your thoughts about the potential underlying mechanisms?

Dr Jones: There are a number of very plausible hypotheses of what it is about childbirth that is such a potent trigger for severe postpartum episodes in women with bipolar disorder. These include the major hormonal changes that occur in the immediate postpartum period, immunological factors, and also the sleep disruption that is almost universal at this time. Our study provides some evidence that sleep disruption may be part of the story. We know that sleep disruption can be an important trigger for manic episodes, but to date there has been little direct evidence [identifying] sleep disruption as a trigger of postpartum mania. 

Psychiatry Advisor: What are the treatment implications for our clinicians?

Dr Jones: Women with bipolar disorder are at high risk for postpartum episodes: Around 50% of deliveries are followed by a mood episode, and around 20% of deliveries are followed by an episode of postpartum psychosis. Women with bipolar disorder have very difficult decisions to make about pregnancy, including weighing the risks and benefits of continuing and stopping medication. Being able to individualize the risk for each woman will help them and their clinicians make these decisions. Asking women about triggering of episodes by sleep disruption may therefore help to individualize the risk.

Psychiatry Advisor: What should be the focus of future research in this area?

Dr Jones: There are limitations with the work reported, particularly asking about past episodes of illness, as this was a retrospective study. Prospective studies of women with bipolar disorder in pregnancy would be very beneficial. In addition, studies with more objective measures of sleep disruption, for example, using actigraph watches, would also be important to conduct.

References

  1. Kendell RE, Chalmers JC, Platz C. Epidemiology of puerperal psychoses. Br J Psychiatry. 1987;150:662-673
  2. Di Florio A, Forty L, Gordon-Smith K, et al. Perinatal episodes across the mood disorder spectrum . JAMA Psychiatry. 2013;70(2):168-175.
  3. Jones I, Craddock N. Familiality of the puerperal trigger in bipolar disorder: results of a family study. Am J Psychiatry. 2001;158(6):913-917.
  4. Wesseloo R, Kamperman AM, Munk-Olsen T, Pop VJM, Kushner SA, Bergink V. Risk of postpartum relapse in bipolar disorder and postpartum psychosis: a systematic review and meta-analysis. Am J Psychiatry. 2016;173(2):117-127.
  5. Lewis KJSDi Florio AForty L, et al. Mania triggered by sleep loss and risk of postpartum psychosis in women with bipolar disorder. J Affect Disord. 2018; 225:624-629.
  6. Lewis KSGordon-Smith KForty L, et al. Sleep loss as a trigger of mood episodes in bipolar disorder: individual differences based on diagnostic subtype and gender. Br J Psychiatry. 2017;211(3):169-174.
  7. Jackson A, Cavanagh J, Scott J. A systematic review of manic and depressive prodromes. J Affect Disord. 2003;74(3):209-217.
  8. Bauer M, Grof P, Rasgon N, Bschor T, Glenn T, Whybrow PC. Temporal relation between sleep and mood in patients with bipolar disorder. Bipolar Disord. 2006; 8(2):160-167.
  9. Bunney BG, Bunney WE. Mechanisms of rapid antidepressant effects of sleep deprivation therapy: clock genes and circadian rhythms. Biol Psychiatry. 2013; 73(12):1164-1171.
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