Transcript:

Bipolar disorder is a condition involving recurring episodes of changes in mood, thinking, and activity that vary in severity, duration, and frequency. These episodes can include a mix of manic or hypomanic and depressive symptoms in the same episode. These are commonly known as mixed episodes.  

The Diagnostic And Statistical Manual Of Mental Disorders, 5th edition (DSM-5) defines hypomania as a distinct period that lasts at least 4 consecutive days during which an individual experiences an abnormal and persistent high mood that can be either elevated or irritable. During this time, the individual may also have an increase in activity or energy that lasts most of the day, nearly every day.

The individual may experience a noticeable change in behavior in three or more of the following symptomatic areas lasting 4 days or more:

• Overinflated self-esteem or grandiosity
• Decreased need for sleep
• Pressured speech
• Racing thoughts
• Distractibility
• Restlessness and
• Risky behavior

Today, clinicians and researchers face a challenge due to the evolving nature of mixed episodes, which has resulted from multiple definitions over time.  

Prior to the DSM-5, the DSM-4 defined a mixed episode as the occurrence of both manic and depressive symptoms lasting at least seven days in an individual with bipolar disorder type I.  

Since then, the DSM-5 removed the term “mixed episode” and introduced “mixed features” as a specifier consisting of three or more symptoms of opposite mood polarity to be applied to manic or hypomanic episodes in bipolar disorder, and major depressive episodes (MDEs), in major depressive disorder (MDD).

A person with mixed features, according to this new definition, could experience any of the following symptoms:   

• Euphoria or depressed mood
• Increased/decreased interest in activities
• Overinflated ego or feelings of worthlessness
• Risky behavior or suicidal acts
• High or low energy
• Reduced need for sleep or early morning awakening
• Loss of appetite or disrupted mealtime, and  
• Racing thoughts or concentration difficulties

The DSM-5 attempts to distinguish between hypomanic or manic episodes, depressive episodes, and episodes with mixed features by using 12-item criteria consisting of symptoms as domains. The 12 diagnostic symptomatic domains are:

• Mood
• Emotional tone
• Thought content
• Manner of speech
• Behavior
• Energy level
• Sleep
• Thoughts
• Duration
• Minimum criteria  
• Appetite and Functioning  

For example, patients who present with manic/hypomanic or depressive episodes with mixed features are thought to have a more severe form of bipolar disorder and may experience more mood swings, irritability, and instability, less interest in enjoyable activities, and thus may have poorer outcomes.  

Patients with mixed mania may also have more frequent and longer episodes, shorter intervals between episodes, higher rates of suicide attempts, and a greater likelihood of substance abuse.

Neurotransmitter imbalance is believed to be one of the mechanisms influencing the different mood states in bipolar disorder.

This imbalance includes an increase in acetylcholine, as seen in the case of depression; catecholamine and cholinergic imbalance, which are seen in mixed episodes; and an increase in dopamine, as observed with mania.

Targeting these neurotransmitters is challenging and often requires a combination of medications, including second and third-generation antipsychotics as well as typical mood stabilizers. Newer anticonvulsants are also showing promise due to their tolerability and effectiveness. In severe cases, electroconvulsive therapy (ECT) may be an option.

To better manage these conditions, clinicians must have a thorough understanding of the clinical characteristics and various aspects of mixed features, as the number of patients experiencing them may be higher based on current DSM-5 criteria.