Diagnosis in Bipolar Disorder: Dealing With Comorbidity

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BIPOLAR UPDATE

In the previous column in this series, there was a discussion of how to improve precision in diagnosing mania and hypomania. A method of improving accuracy in eliciting a history of these mood states was described in some detail, and the importance of identifying possible prebipolar depressions that may be followed by a first mania at a later point was also stressed. In the present column, the emphasis will be on the diagnosis of comorbid disorders that add to the symptoms presented by patients with bipolar disorder so that these symptoms can be targeted with the appropriate interventions. There is a tendency by some prescribers to target symptoms (such as insomnia, anxiety, or irritability) with medications that they believe to be effective for those symptoms, regardless of the diagnosis generating them. The more evidence-supported approach would be to treat those disorders with the medications that have been found most effective for them.¹

When there is apparent comorbidity, the clinician should first delineate the criteria-based DSM-5-TR diagnoses that are present. This process takes time. The evaluation may need to be spread over several appointments before reaching the complete diagnostic impression. Ninety minutes is frequently required to evaluate a new patient with complex issues in this manner, including the time for reviewing the previous record and writing the assessment.²

Often, in current managed care and public sector environments, clinicians are not allowed this much time (if employed) or may elect to take less time (in private practice) because of financial considerations and pressures. Experienced clinicians may convince themselves that they can do an adequate psychiatric assessment in less time and choose the most appropriate medications for the correct diagnoses; however, brief evaluations followed by quick prescribing often result in errors, and patients experience them as rushed and unsatisfying. These practices undermine confidence in and respect for our profession.² The first clinical encounter is an important experience that sets the stage for the ongoing therapeutic alliance with the patient.

So, it is crucial to take the necessary time to establish the diagnoses. Then, determine (in collaboration with the patient) the additional diagnoses that seem to be contributing the most to the patient’s distress or dysfunction, and treat those issues first with what the evidence best supports. For example, active and severe substance use disorders may deserve priority for management. Even cannabis use disorder can exacerbate bipolar disorder,³ and it may be essential to make a strong effort to persuade the patient to address this disorder first before introducing or modifying the medications prescribed for bipolar disorder or other potential comorbidities.

PTSD

Posttraumatic stress disorder (PTSD) is a very common comorbidity with bipolar disorder, especially in veterans. The irritability of patients with PTSD, when triggered by events, interactions, or memories of their trauma, can be mistaken for the irritable mood that is one of the possible mood types in the DSM-5-TR A criteria for bipolar mania (along with elevated or expansive mood).

Valproate is often prescribed for patients with irritable mood thought to be resulting from bipolar mania. However, if the irritability is due to PTSD, it will likely not respond to valproate, as was demonstrated in data from 2 negative controlled studies.^4,5 Clinicians should determine if the irritable mood occurs in discrete episodes of mania lasting at least several days and accompanied by the other manic symptoms in the mania criteria (noting that you need 4 other symptoms, not 3, of the 7 that are listed, if the mood is only irritable). If not, and the irritable mood invariably occurs when triggered by events that produce reexperiencing and the fight-or-flight adrenalized “zero to 100” immediate reaction to those triggers, then there is a good chance it could be due to PTSD. For these patients, the treatment would likely be more effective with an anti-adrenaline agent in the PTSD armamentarium, such as prazosin or clonidine.⁶

ADHD

Attention-deficit/hyperactivity disorder (ADHD) is another common comorbidity with bipolar disorder. Most adults with ADHD have emotional dysregulation, and this typically presents as chronic overreactions to various stresses.7 This, too, can be confused with the irritable mood of a manic episode.

Stimulants have been found effective for this emotional dysregulation as well as for the focus, concentration, and hyperactivity of patients with ADHD.⁷ Therefore, it is important to take the time to make this diagnosis, using the DSM-5-TR criteria. There are 18 symptoms in the criteria, 9 for inattention and 9 for hyperactivity; you need at least 5 to meet the criteria for each subtype. Consider which symptoms could be attributed to ADHD and which occur mainly or to a greater extent during discreet manic episodes. Stimulants can be used safely to treat ADHD in patients with comorbid bipolar disorder, preferably methylphenidate.⁸

Sleep Impairment

Sleep impairment is common in many diagnoses that are often comorbid with bipolar disorder. In mania, of course, there is a decreased need for sleep, and the treatment of choice would be an antimanic agent rather than a hypnotic or trazodone, as appears to be commonly used. However, very often, there are other contributing causes of the insomnia depending on the timing of this symptom. There are medical causes to be ruled out or managed, such as sleep apnea, restless leg syndrome (RLS), caffeinism, nocturia from prostate hypertrophy or diabetes, and pain syndromes, to name a few. Among psychiatric comorbidities, there is, again, PTSD—which is invariably associated with sleep disturbance, including difficulty initiating sleep and difficulty maintaining it due to nightmares, disturbed awakenings (without recalling a nightmare), and sleep terrors observed or heard by a bed partner.

A thorough evaluation of insomnia is always indicated to identify the leading cause(s), including asking patients about all those examples of PTSD-related sleep disturbance, not just nightmares. This is a much better approach than the shortcut of treating the symptom of insomnia by proceeding through a list of favorite hypnotics that might include antihistamines, benzodiazepines, zolpidem, gabapentin, melatonin, trazodone, mirtazapine, quetiapine, valproate, or some combination of these. Depending on the causes of the sleep problems that are identified (assuming it is not mania), the proper treatment might be continuous positive airway pressure, effective pain management, pramipexole for RLS, reduction of caffeine use, or prazosin for the nightmares and disturbed awakenings of PTSD.⁹

Anxiety

Anxiety symptoms are very common in patients with bipolar disorder. If the symptoms are due to an anxiety disorder, it may be reasonable to address those symptoms with antianxiety agents like buspirone, hydroxyzine, benzodiazepines, or possibly gabapentin. However, it is important to recognize that there may be another disorder that is the primary cause of the anxiety. Again, one option is PTSD, in which the anxiety is related to events, fears, triggers, and being unable to avoid reminders of their traumatic experiences. Buspirone and benzodiazepines have not shown efficacy for PTSD-related anxiety, and antidepressants are probably best avoided because of the comorbid bipolar disorder. Prazosin, once again, might be the preferred treatment.¹⁰

Concluding Thoughts

Comorbidities in patients with bipolar disorder are the rule rather than the exception. Good clinical practice requires us to spend the necessary time to complete a comprehensive evaluation to tease out the various comorbidities that are present and then to treat each diagnosis appropriately.

Dr Osser is an associate professor of psychiatry at Harvard Medical School in Boston, Massachusetts; a psychiatrist at the Veterans Affairs (VA) Boston Healthcare System, Brockton Division; and codirector of the VA National Bipolar Disorders TeleHealth Program. Dr Osser is a member of Psychiatric Times Editorial Board. He reports no conflicts of interest concerning the subject matter of this article.

References

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