Bipolar Depression 17 Oct, 2024 Read Time: 3 mins

Clues to Differentiate Bipolar Disorder

Distinguishing between unipolar and bipolar depression – and between bipolar I and II depression – can be a challenge even for experienced clinicians. Yet accurate diagnosis is critically important since it informs appropriate treatment selection. During a virtual educational webinar called “Improving the Lives of Patients with Bipolar Disorder” offered by the Neuroscience Education Institute (NEI), Dr. Henry Nasrallah, a Professor of Psychiatry, Neurology & Neuroscience at the University of Cincinnati School of Medicine, offered his top clinical clues to navigate the recognition and diagnosis of bipolar disorder. 

Burden of bipolar disorder

Bipolar disorder is a common and highly burdensome mental illness that is estimated to affect nearly one million Canadians (the estimated prevalence among Canadian adults was 2.1% in 2022).1 It is the second leading cause of disability among mental health and physical conditions worldwide2 and is a serious illness that can be life shortening by 10 to 20 years due in part to the high risk of suicide.3,4 

Up to 1 in 5 patients with bipolar disorder die by suicide4

Diagnostic dilemma: Recognizing the type of major depression

Major depression can look very similar in patients with unipolar or bipolar disorder. Up to three-quarters of patients with bipolar disorder are misdiagnosed, most commonly with unipolar depression, since patients usually present for care during depressive phases of illness.5 However, misdiagnosis can have serious repercussions on patients since unipolar and bipolar depression are treated differently; moreover, utilization of antidepressants in patients with unrecognized bipolar disorder can trigger episodes of mania or hypomania.5 This makes it critical to accurately diagnose bipolar disorder so that it can be appropriately managed.

A first step is to identify a patient’s subtype of depression 

Clues to differentiate bipolar from unipolar depression

Dr. Nasrallah offered 5 clues to help clinicians differentiate bipolar from unipolar depression when a patient presents with a major depressive episode. These clues should alert the clinician of the likelihood of an underlying bipolar illness: 

  1. Demographics: Early age of onset of the first depressive episode (<25 years old) or postpartum onset
  2. Family history: Diagnosis of a mood or substance use disorder or history of suicide among first degree relatives
  3. ‘Antidepressant misadventures’: Cycling through multiple antidepressant failures or antidepressant-induced mania or hypomania 
  4. The 3 C’s − Comorbidity, Chronicity and Chaos: Psychiatric and medical comorbidities are the rule rather than the exception in bipolar disorder, most commonly anxiety, substance use, obesity, migraine and diabetes, as well as relationship and vocational dysfunction
  5. Manic or hypomanic symptoms: Commonly presenting as racing thoughts and/or rapid speech, but persistent irritability lasting hours to days should also be a red flag 

Several clues can alert the clinician to an underlying bipolarity when patients present with a major depressive episode

Critical differences between bipolar I and bipolar II disorder

After differentiating unipolar from bipolar depression, it is imperative to distinguish between bipolar I and II disorders since they are managed differently. Moreover, patients with bipolar II disorder may have a higher risk of suicidality compared to bipolar I disorder.6 Dr. Nasrallah suggested 3 clues that point to an underlying bipolar II disorder:

  1. Higher frequency and duration of depressive episodes, leading to significantly more time spent in depressive illness
  2. Longer diagnostic delay
  3. Higher risk of comorbid psychiatric illness notably anxiety, personality disorders, attention deficit/hyperactivity disorder, and eating disorders

Clinicians may need to ‘dig’ deep during history-taking to uncover hypomanic episodes

Dr. Nasrallah concluded that both types of bipolar depression have severe lows, but bipolar I disorder has higher highs whereas bipolar II has less frequent and lower highs, which can be more difficult to recognize.7 Taking the time to accurately diagnose bipolar disorder through a careful history is important to minimize the potentially tragic outcomes of this serious and disabling illness.

Our correspondent’s highlights from the symposium are meant as a fair representation of the scientific content presented. The views and opinions expressed on this page do not necessarily reflect those of Lundbeck.

References

  1. Stephenson. Insights on Canadian Society: Mental disorders and access to mental health care. Statistics Canada: September 22, 2023. Available at Mental disorders and access to mental health care (statcan.gc.ca). Accessed July 11, 2024.
  2. Alonson et al. Molec Psychiatr 2011;16:1234-46.
  3. McIntyre RS et al. Lancet 2020;396(10265):1841-56.
  4. Gergel et al. Lancet Psychiatry 2024 Jun 14:S2215-0366(24)00172-X. Online ahead of print.
  5. Frye et al. Psychiatr Serv 2005;56:1529-33.
  6. Karanti et al. Bipolar Disord 2020;22(4):392-400.
  7. Regeer et al. Int J Bipolar Disord 2015;3:22.