This week’s podcast was stimulated by a letter from a listener:

My husband and I have been married for about a year and we are in our late twenties. I knew my husband had serious depression when he was in college, but he's been fine since then. Recently, though, I've been noticing something different. He will get very irritable with me for several days, which is really unlike him. He seems agitated and like he can't settle down, and at night he sleeps very poorly, so that's probably adding to it all. I got really concerned last week when I looked at his credit card statement and there were some random expenses that just didn't make any sense to me, but he got very nasty with me when I tried to ask him about it. Now, this week, everything is just fine again, but I am so worried about these times because it feels like he's having a personality change. Should I take him to a counselor? — Grace

I discussed this case with my colleague, psychiatrist Joe Zealberg, a retired professor of psychiatry at the Medical University of South Carolina. We agreed that the most likely diagnosis was bipolar disorder, with a “rule-out” of substance abuse and hyperthyroidism. Several aspects of this case are notable and could lead to a missed diagnosis. First, Grace’s husband had an agitated, irritable mood. Commonly, a manic mood is thought of as euphoric, but clinically, an irritable mood is often more common.

Second, the symptoms were not severe and evidently abated after several days. Could such a relatively mild presentation really warrant the quite serious diagnosis of bipolar disorder, especially since this could lead to long-term treatment?

The tip-off, for both Joe and me, was the cardinal symptom of poor sleep. Certainly, to have an irritable mood from time to time is not uncommon—not at all. But it is the co-existence of three cardinal symptoms of mania: poor sleep, agitated mood, and excessive spending, and the history of a previous significant depressive episode, that raise the index of suspicion for bipolar disorder. If there were a family history of bipolar disorder the likelihood of a bipolar disorder diagnosis would be even higher.

Let’s imagine that your clinician is highly suspicious but not 100% positive that this is bipolar disorder, and the young man goes into a serious depressive episode. Now the plot has thickened in a very worrisome way: If he has a bipolar vulnerability, treating his serious depression with an antidepressant could trigger a manic episode—a phenomenon called “switching," in which severe, manic episodes can be catastrophic, with sufferers sometimes becoming violent, highly inappropriate, or sexually impulsive. Hallucinations and delusions can occur, and sometimes hospitalization is essential to protect the safety of the sufferer and the family.

Yet, it is also a difficult path to recommend treatment with mood stabilizers in the absence of absolute certainty of the diagnosis. Mood stabilizing agents, such as lithium, antipsychotic agents, and/or anticonvulsant medications, all have potential side effects. The only responsible path is to have an open discussion of the issues with the patient and family and for the clinician and the family to make the decision together. If the family refuses mood stabilizers and wants antidepressants, the clinician should fully educate them about early warning signs of a manic “switch” with an emphasis on poor sleep as an early warning sign of incipient mania. Antidepressants should be started at very, very low doses and a family member should be assigned to keep an eye on the patient and reach out to the clinician at the first sign of switching.

Zealberg stressed how important the role of the family is in the diagnosis of bipolar disease. The disorder can present in an wide variety of ways. At its most extreme, a full-blown manic attack presents with weeks of sleeplessness, hallucinations, delusions, and sometimes terrifying violent behavior. At its most subtle, a person may have had a history of recurrent depressions with a manic episode occurring for the first time

Further complicating the diagnosis, it is extremely common for patients to have no memory of manic moods, even when they have been severe. A conversation with a family member helps not only to confirm the diagnosis but to create a supportive path for the patient moving forward.