Transcript:

Delineating between unipolar depression, which is sometimes called Major Depressive Disorder, and bipolar depression, can be challenging for providers. The reason for this is that unipolar and bipolar depression have similar overlapping symptoms. Key differences lie in the presence or absence of mania and the course of the condition over time.  

Interestingly, a large-scale study revealed that the onset for bipolar depression   came 6 years before that of unipolar depression. While the diagnostic boundary between unipolar depression and bipolar depression is distinct, their symptoms overlap which makes diagnosis difficult. Therefore, differentiating between the often-complex presentation of these disorders requires significant diagnostic skill.

For example, both conditions share depressive symptoms of sadness, hopelessness, pessimism, anxiety, sleep problems, and potentially suicidal thoughts. Symptoms of unipolar depression include changes in appetite, difficulty concentrating, fatigue, feeling emotionally numb, and moving or speaking slowly.

Bipolar depression includes the same symptoms of unipolar depression but also includes mania, hypomania, or a mixed presentation of both. While unipolar and bipolar depression share symptoms, there can be a difference in their frequency. According to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), a major depressive disorder is defined by at least 5 of the symptoms shown for a period of 2  weeks or more. One of these symptoms must include depressed mood and/or loss of interest or pleasure.

As mentioned, a diagnosis of bipolar disorder is defined by the presence of a single episode of mania or psychosis, whereas a diagnosis of unipolar is devoid of instances of elevated mood. The DSM-5 criteria for symptoms of a manic episode are shown here. Patients can display delusions of grandiosity paired with symptoms of irritability, jealousy, and suspiciousness. The sudden ability to complete numerous tasks at once, often at the expense of regular sleep, can mask the severity of the manic episodes. As the patient may have been depressed for a period of time, this perceived increase in functional ability can be met with a sense of relief.

Some symptoms can be associated with mania, as shown here, but are not used for  the purpose of diagnosis. During acute manic episodes, additional symptoms such as delusions, hallucinations, confusion, and violence may occur. It is important to note that when combined, these symptoms place patients with bipolar disorder at higher risk of suicide.

Despite overlapping symptoms between the 2  conditions, an accurate diagnosis is important for optimizing treatment approaches. Antidepressants are commonly used to treat unipolar depression. However, use of unopposed antidepressants in the treatment of bipolar depression is a concern. Studies have shown associations between antidepressant treatment in bipolar depression and treatment-emergent mania, mood destabilization, dysphoria induction, and suicidality.

When deciding on a treatment for bipolar disorder, it is important to note that non-serotonergic agents are the best choice for single therapy due to their ability to manage both manic and depressive symptoms in patients.

In this video we have discussed the complexities in identifying the diagnostic and treatment differences between unipolar depression and bipolar depression.

References: 

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