Major depressive disorder affects an estimated 14.8 million people 18 and older, or about 6.7% of the U.S. population.1\u00a0Bipolar disorder affects an estimated 5.7 million of those 18 and older, or about 2.6% of the U.S. population.2 Multiple research studies have shown that women have a heightened risk of developing simultaneous or overlapping symptoms of mania and depression. When depression is the most pronounced symptom, it's possible to overlook manic episodes, which often leads to inaccurate diagnoses. Bipolar Disorder in Women The American Psychiatric Association (APA) recognizes three primary types of bipolar disorder, which all involve distinct changes in mood, energy and activity levels. Although the different types have specific defining characteristics, there are some similarities among these mental health disorders. During a manic episode, people may feel exuberantly joyful or uncomfortably irritable; during a depressive episode, they may experience desperate sadness or hopelessness. The three types are as follows: Bipolar I disorder This is characterized by one or more manic episodes or mixed episodes (symptoms of both mania and depression) that last at least seven days. Typically, a person will also experience periods of depression with episodes lasting at least two weeks. It is common for episodes to be so severe that immediate hospitalization is warranted.3 Bipolar II disorder This is characterized by a pattern of one or more major depressive episodes and at least one hypomanic episode. Patients do not experience the full-blown manic episodes that are indicative of bipolar 1. In fact, this type is sometimes misdiagnosed as major depression if hypomanic episodes go unrecognized or unreported.3 Cyclothymic disorder This is a milder type with numerous alternating periods of hypomanic and depressive symptoms. The episodes generally have a duration of at least two years in adults and one year in children and adolescents. Of course, the severity of this type may change over time.3 There are several other terms which can further define bipolar disorder. Cases that do not follow the above patterns are known as not otherwise specified. The term rapid cycling can describe four or more manic, hypomanic or depressive episodes in any 12-month period. Rapid cycling produces unusually frequent shifts in mood, can affect patients with any of the three types and may be temporary.3\u00a0While mixed bipolar disorder is not a type, the term is often indicates people who have episodes of mania with additional symptoms of depression or conversely, episodes of depression with additional symptoms of mania. The APA changed its official diagnostic term for these mental health conditions from \u201cmixed episodes\u201d to \u201cmixed features\u201d in 2013.4 Bipolar Disorder Symptoms in Women Although the overall incidence rates of bipolar are similar in men and women, there are some distinctive gender differences, as follows: \tWomen develop bipolar II disorder, bipolar depression, and rapid cycling more commonly than men with bipolar disorder. \tWomen face major delays in treatment of up to 11 years from onset due to misdiagnosis or a failure to diagnose, compared to a seven-year delay in men.5 \tSome experts believe the statistically higher prevalence of mixed bipolar symptoms in women may be attributable to their more demonstrative temperament.6 \tOverall findings indicate that the risk of relapse in bipolar women during pregnancy and\/or postpartum is considerable. Women who discontinue use of mood stabilizers during pregnancy may be the most at risk.7 \tBipolar women are quite vulnerable to postpartum depression and the more severe postpartum psychosis, which is thought to be a variant of bipolar disorder. A 2008 study of 56 women who received referrals for postpartum depression found that more than half had some type of bipolar disorder.6 Depression or Mixed Bipolar Disorder? In a 2015 study published in Psychopathology in Women, researchers analyzed the possibility that at least some\u00a0women diagnosed with depression\u00a0actually had symptoms that met the criteria for a mixed bipolar diagnosis. The research team preliminarily identified anxiety and irritability as the most common distinguishing characteristics of mixed bipolar disorder in women. They also identified a range of more specific problems associated with irritability including panic attacks, phobia-related anxiety symptoms, a generalized sense of unease, loss of energy, recurring bouts of \u201cdown\u201d or negative thinking, thoughts of suicide, withdrawal from social situations, decreased mental sharpness, and also a sense of detachment from self. The authors concluded that in some cases, the existence of major depression with mixed symptoms may result in doctors diagnosing a depressive illness when bipolar disorder would be a more accurate diagnosis. For that reason, they urged doctors to perform a later follow-up evaluation on any person diagnosed with major depression with mixed symptoms in order to reassess the potential presence of bipolar disorder.8 References \tDepression Statistics. Depression and Bipolar Support Alliance website.\u00a0http:\/\/www.dbsalliance.org\/site\/PageServer?pagenameeducation_statistics_depressionAccessed June 12, 2016. \tBipolar Disorder Statistics. Depression and Bipolar Support Alliance website.\u00a0http:\/\/www.dbsalliance.org\/site\/PageServer?pagenameeducation_statistics_bipolar_disorderAccessed June 12, 2016. \tTypes of Bipolar Disorder. Depression and Bipolar Support Alliance website.\u00a0http:\/\/www.dbsalliance.org\/site\/PageServer?pagenameeducation_bipolar_types\u00a0Accessed June 12, 2016. \tHelp With Bipolar Disorders. American Psychiatric Association website.\u00a0https:\/\/www.psychiatry.org\/patients-families\/bipolar-disorders\u00a0Accessed June 12, 2016. \tSit DK. Women and Bipolar Disorder Across the Life Span. J Am Med Womens Assoc. Spring 2004: 59(2): 91\u2013100. \tBipolar Disorder Is Different for Women. Health website\u00a0http:\/\/www.health.com\/health\/condition-article\/0,,20274376,00.html\u00a0Updated May 1, 2009. Accessed June 12, 2016. \tA View of Bipolar Disorder Across the Life Span. Medscape website.\u00a0http:\/\/www.medscape.org\/viewarticle\/458703\u00a0Published July 23, 2003. Accessed June 12, 2016. \tGonz\u00e1lez-Pinto A, L\u00f3pez-Zurbano S, L\u00f3pez P. Mixed Forms in Bipolar Disorder and Relation to Gender. In S\u00e1enz-Herrero M, ed.\u00a0Psychopathology in Women. New York, NY: Springer: 2015:661-677.