Abstract
The paper offers an overview of bipolar disorder based on the DSM-5 criteria. After a brief discussion of the two types of the disease, special prominence is made on bipolar I disorder. Diagnostic features characterizing bipolar I, which are four, are described in detail. Potential concurrent episodes, which are not obligatory for the diagnosis, are mentioned. Attention is given to the illness’s etiology, including the typical diagnosis age and heritability.
The prevalence of the disease is analyzed, with due respect being paid to global changes over several decades. To demonstrate the difficulty in diagnosing bipolar I, a comparison between it and major depressive disorder is made. Finally, the aspects of comorbidity and differential diagnoses are noted. In the concluding section, a summary of findings is offered. The paper may be of use for those looking for reliable and relevant information about bipolar disorder.
Introduction
DSM-5 draws a line between bipolar and related disorders and depressive ones. According to DSM-5, the former include bipolar I and II disorder, substance/medication-induced bipolar and related disorder, cyclothymic disorder, and other specified and unspecified bipolar and related disorder (American Psychiatric Association [APA], 2013). The present paper offers an overview of bipolar I and II and puts an emphasis on bipolar I symptoms, etiology, prevalence, and risk factors.
Two Types of Bipolar Disorder: The DSM-5 Criteria
Prior to the DSM-5 edition, bipolar II was considered a milder form of bipolar I. Such an opinion was justified by the fact that bipolar I involved a manic episode, whereas bipolar II involved a major depression and a hypomanic episode (APA, 2013). However, due to the amount of time bipolar II patients spend in depression and the severity of their social- and work-related impairment caused by mood instability, bipolar II is no longer viewed as less serious.
To be diagnosed with bipolar I, one needs to have been diagnosed with a manic episode preceded or followed by major depressive or hypomanic episodes. The diagnosis of bipolar II presupposes a current or past hypomanic episode a current or past major depressive episode (APA, 2013). While the two types of disorder are similar, scholars have not attained a unanimous opinion on their etiology yet (Song et al., 2018).
Research by Song et al. (2018) suggests that there is an etiology distinction between bipolar I and II based on genetic variances. Specifically, the odds ratio of bipolar I, according to researchers, is 17.0 in first-degree relatives of bipolar I patients, whereas the odds ratio of bipolar II is 9.8 (Song et al., 2018). Differences between the two conditions can also be observed in other dimensions.
The main distinction in diagnostic features is the presence of a manic episode in bipolar I and one or more depressive episodes plus at least one hypomanic episode in bipolar II. Hypomanic and major depressive disorders may occur in bipolar I, but they are not obligatory for the diagnosis (APA, 2013). What concerns prevalence, its rates do not differ by gender in both types (Ferrari et al., 2016). Comorbidity of both bipolar I and II presupposes co-occurring mental disorders, the most common ones being anxiety and substance use disorders.
Bipolar I Disorder
Symptoms and Diagnostic Features
Bipolar I is characterized by a manic episode, which incorporates four major features. First of all, there is a distinct period of “abnormally and persistently elevated, expansive, or irritable mood and abnormally and persistently increased goal-directed activity or energy” (APA, 2013, p. 124). Such a period should last for one week and be present for most of the day. Secondly, at least three of the following symptoms should be present during the increased energy and mood disturbance period. These include augmented self-esteem, a low need for sleep, excessive communication, a rapid movement of ideas, absent-mindedness, increased agitation or activity, and engaging in potentially hazardous activities (APA, 2013).
The third diagnostic feature is a considerable mood disturbance, and the fourth one is the impossibility to attribute the episode to substance-related effects. Hypomanic and depressive episodes may occur in bipolar I patients, but they are not required for the diagnosis of the disorder.
Etiology
Researchers continue searching the etiological disparities between bipolar I and bipolar II. As Song et al. (2018) report, not only severity but also the etiology of the two types is different. Family-based studies of the Swedish population allow determining etiological boundaries between the two conditions. There is a lower rate of female patients with bipolar I, and their diagnosis age and calendar year of birth are typically earlier than of those suffering from bipolar II (Song et al., 2018). The heritability of bipolar I in the research group was 57% (Song et al., 2018). Thus, when evaluating individuals for bipolar disorder, it is crucial to take into account their family history of the disease.
Prevalence and Development
Modern algorithms allow estimating the 12-month and lifetime prevalence of DSM-5 bipolar disorder. Fassassi, Vandeleur, Aubry, Castelao, and Preisig (2014) report that the lifetime prevalence for bipolar I am 1.0%. Scholars note that despite modified diagnostic criteria of bipolar disorder given in DSM-5, prevalence estimates for bipolar I (as well as for bipolar II) have not changed much. Additionally, Fassassi et al. (2014) note that lifetime prevalence statistics do not vary by sex.
Findings from the Global Burden of Disease Study 2013 indicate a 49.1% increase in bipolar disorder prevalence at a global level between 1990 and 2013 (Ferrari et al., 2016). As of 2013, nearly 10 million people in the world lived with disabilities caused by bipolar disorder (Ferrari et al., 2013). Taking into account the prevalence rates, it is evident that further investigations into the etiology of the condition are needed in order to find appropriate prevention and treatment measures.
Bipolar I and Major Depressive Disorder
One of the reasons why bipolar I may be confused with major depressive disorder is that patients with both conditions demonstrate similarities in brain activation during the depression. According to research by Cerullo et al. (2014), the two illnesses have common depressive symptoms even though their course is different. Such closeness between depressive symptoms presupposes “significant overlap in brain pathways underlying neurovegetative, mood, and cognitive symptoms of depression” (Cerullo et al., 2014, p. 703). Researchers have found considerable similarities in cortico-limbic regions of bipolar I and major depressive disorder patients.
Meanwhile, divergences have been observed in visual processing regions (Cerullo et al., 2014). The evidence suggests that a thorough examination of patients with bipolar I symptoms is required due to the risk of mistaking it for depressive disorder.
Risk Factors
There are certain environmental and genetic factors likely to increase the risk of developing bipolar I. The main environmental risks include low income and single or separated marital status (APA, 2013). Genetically, the most severe and persistent risk is a family history of a disorder. Individuals whose relatives have bipolar I are ten times more likely to have it, too. First-degree relatives have the highest risk of developing the disorder (Song et al., 2018). Having had a manic episode also increases the likelihood of psychotic features emerging in the future.
Differential Diagnoses and Comorbidity
Differential diagnoses for bipolar I include major depressive and panic disorder, generalized anxiety and posttraumatic stress disorder, substance-induced bipolar disorder, hyperactivity and personality disorder, and disorders with prominent irritability. All of these conditions share some symptoms, so it may be difficult to identify which of the disorder type a patient has. With the help of thorough examination and based on clinical evidence, bipolar I disorder can be distinguished from others (APA, 2013). The illness is frequently accompanied by other mental issues, such as anxiety disorders, impulse-control disorders, and substance use disorders.
Conclusion
Both bipolar I and II disorder are severe mental illnesses affecting patients negatively and making them unable to maintain a satisfactory lifestyle. Although some changes have been made in the DSM-5 when differentiating between the two conditions, bipolar I am still considered slightly more dangerous than bipolar II. However, both conditions have similarities in symptoms, prevalence, etiology, and differential diagnoses. The prevalence of bipolar I am rather high, and the incidence has drastically increased from 1990 to 2013. Hence, scholars are constantly working on finding out predictors of the disease and eliminating its negative consequences on patients.
References
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: American Psychiatric Publishing.
Cerullo, M. A., Eliassen, J. C., Smith, C. T., Fleck, D. E., Nelson, E. B., Strawn, J. R., … Strakowski, S. M. (2014). Bipolar I disorder and major depressive disorder show similar brain activation during depression. Bipolar Disorders, 16(7), 703–712. Web.
Fassassi, S., Vandeleur, C., Aubry, J.-M., Castelao, E., & Preisig, M. (2014). Prevalence and correlates of DSM-5 bipolar and related disorders and hyperthymic personality in the community. Journal of Affective Disorders, 167, 198–205. Web.
Ferrari, A. J., Stockings, E., Khoo, J.-P., Erskine, H. E., Degenhardt, L., Vos, T., & Whiteford, H. A. (2016). The prevalence and burden of bipolar disorder: Findings from the Global Burden of Disease Study 2013. Bipolar Disorders, 18(5), 440–450. Web.
Song, J., Kuja-Halkola, R., Sjölander, A., Bergen, S. E., Larsson, H., Landén, M., & Lichtenstein, P. (2018). Specificity in etiology of subtypes of bipolar disorder: Evidence from a Swedish population-based family study. Biological Psychiatry, 84(11), 810–816. Web.