Symptoms of MDD May Actually Indicate Another Psychiatric Disorder

A session at the 2017 Neuroscience Education Institute (NEI) Congress presented by Stephen M. Stahl, MD, PhD, adjunct professor of psychiatry, University of California San Diego, emphasized the importance of making an accurate diagnosis in patients presenting symptoms of depression.

Several psychiatric disorders are commonly misdiagnosed as major depressive disorder (MDD) but may actually be bipolar disorder, pseudobulbar affect disorder (PBA), and post-traumatic depression (PTD), said the NEI chairman.

Stahl began the session by explaining that individuals with unipolar depression and “a bit of mania,” also known as depression with mixed features (DMX), are more likely to have an eventual diagnosis conversion to bipolar disorder. Indications of this can be seen from many clues across the spectrum including family history of bipolar disorder, suicidality, severe depression, antidepressant remission, and impulse control, said Stahl.

“The prognosis for depression with co-occurring (hypo)mania is much worse than for pure unipolar depression or bipolar depression without mixed features,” said Stahl.

Symptoms most commonly seen in DMX include: irritability, distractibility, psychomotor agitation, racing/crowded thoughts, increased talkativeness, emotional lability, and rumination.

Next, Stahl discussed PBA disorder, which occurs in the context of brain injury, including traumatic brain disorder (TBI), stroke, Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), and multiple sclerosis. PBA is characterized by uncontrollable, inappropriate laughing or crying. For psychiatrists, the most inclusive term for the disorder is involuntary emotional expression disorder.

Symptoms of the disorder include: pathological crying and laughing, irritability, aggression, and unpredictable and rapidly changing emotions. Treatment for the disorder include selective serotonin reuptake inhibitors and tricyclic antidepressants. Both therapies can help reduce the frequency and severity of PBA episodes and are typically prescribed at lower doses than for depression.

“PBA is often underrecognized, misdiagnosed, and undertreated,” said Stahl. “Only 40% of patients who discuss PBA symptoms with their clinician are diagnosed.”

The reason PBA is so frequently misdiagnosed is because is it often mistaken for depression, explained Stahl. However, there are several distinctions—the duration of a PBA episode is shorter, crying is not congruent with subjective mood in PBA, and other symptoms of depression are not associated with PBA.

For patients with TBI, depression is the most common psychiatric complication, said Stahl. More than 50% of patients with moderate to severe TBI will experience a depressive episode in the first year post injury, and they have a risk of suicide that is 5 times that of the general population.

PTD is an adjustment-based depression that may occur rather than biologically based depression after TBI. The difference between MDD and PTD is that PTD is characterized by more irritability, anger, and aggression versus sadness or fearfulness.

“Symptoms that are seemingly indicative of MDD may actually be manifestations of a different psychiatric illness,” concluded Stahl. “Making an accurate differential diagnosis in patients presenting with symptoms of depression is critical to the implementation of optimal patient care.”