Overlapping symptoms may obscure comorbid bipolar illness
An adult with function-impairing inattention could have attention-deficit/hyperactivity disorder (ADHD), bipolar disorder (BD), or both. Comorbid ADHD and BD often is unrecognized, however, because patients are more likely to report ADHD-related symptoms than manic symptoms.1
To help you recognize comorbid ADHD/BD—and protect adults who might switch into mania if given stimulants or antidepressants—this article describes a hierarchy to diagnose and treat this comorbidity. Based on the evidence and our experience, we:
- discuss how to differentiate between these disorders with overlapping symptoms
- provide tools and suggestions to screen for BD and adult ADHD
- offer 3 algorithms to guide your diagnosis and choice of medications.
Clinical challenges
Prevalence is unclear. Adult ADHD—with an estimated prevalence of 4.4%2—is more common than BD. Lifetime prevalences of BD types I and II are 1.6% and 0.5%, respectively.3 Studies of ADHD/BD comorbidity suggest wide-ranging prevalence rates:
Underdiagnosis. Adult ADHD/BD is a more severe illness than ADHD or BD alone and is highly comorbid with agoraphobia, social phobia, posttraumatic stress disorder, and alcohol or drug addiction. Adults with ADHD/BD have more frequent affective episodes, suicide attempts, violence, and legal problems.4 Diagnosing this comorbidity remains a challenge, however, because:
- identifying which symptoms are caused by which disorder can be difficult
- BD tends to be underdiagnosed9
- patients often misidentify, underreport, or deny manic symptoms1,10,11
- if a patient presents with active bipolar symptoms, DSM-IV-TR criteria require that ADHD not be diagnosed until mood symptoms are resolved.
Overlapping symptoms. ADHD and bipolar mania share some DSM-IV-TR diagnostic criteria, including talkativeness, distractibility, increased activity or physical restlessness, and loss of social inhibitions (Table 1).12 Overlapping symptoms also are notable within ADHD diagnostic criteria (Table 2). In the inattention category, for example, “easily distracted by extraneous stimuli,” “difficulty sustaining attention in tasks,” and “fails to give close attention to details” are considered 3 separate symptoms. In the hyperactivity category, “often leaves seat,” “often runs about or climbs excessively,” and “often on the go, or often acts as if driven by a motor” are 3 separate symptoms.
Given ADHD’s relatively loose diagnostic criteria and high comorbidity in adults with mood disorders, the question of whether adult ADHD/BD represents comorbidity or diagnostic overlap remains unresolved. For the clinician, the disorders’ nonoverlapping features (Table 1) can assist with the differential diagnosis. For example:
- ADHD symptoms tend to be chronic and BD symptoms episodic.
- ADHD patients may have high energy but lack increased productivity seen in BD patients.
- ADHD patients do not need less sleep or have inflated self-esteem like symptomatic BD patients.
- Psychotic symptoms such as hallucinations or delusions might be present in severe BD but are absent in ADHD.
Table 1
Overlap between DSM-IV-TR diagnostic criteria for ADHD and bipolar mania
| Overlapping symptoms | |
|---|---|
| ADHD | Bipolar mania |
| Talks excessively | More talkative than usual |
| Easily distracted/jumps from one activity to the next | Distractibility or constant changes in activity or plans |
| Fidgets Difficulty remaining seated Runs or climbs about inappropriately Difficulty playing quietly On the go as if driven by a motor | Increased activity or physical restlessness |
| Interrupts or butts in uninvited Blurts out answers | Loss of normal social inhibitions |
| Nonoverlapping symptoms | |
| ADHD Forgetful in daily activities Difficulty awaiting turn Difficulty organizing self Loses things Avoids sustained mental effort Does not seem to listen Difficulty following through on instructions/fails to finish work Difficulty sustaining attention Fails to give close attention to details/makes careless mistakes | |
| Bipolar mania Inflated self-esteem/grandiosity Increase in goal-directed activity Flight of ideas Decreased need for sleep Excessive involvement in pleasurable activities with disregard for potential adverse consequences Marked sexual energy or sexual indiscretions | |
| ADHD: attention-deficit/hyperactivity disorder | |
| Source: Adapted and reprinted with permission from reference 12 | |
Table 2
DSM-IV-TR diagnostic criteria for attention-deficit/ hyperactivity disorder
| Inattention |
≥6 symptoms have persisted ≥6 months to a degree that is maladaptive and inconsistent with developmental level. The patient often:
|
| Hyperactivity/impulsivity |
≥6 symptoms have persisted ≥6 months to a degree that is maladaptive and inconsistent with developmental level. The patient often:
|
| Diagnosis requires evidence of inattention or hyperactivity/impulsivity or both |
| Some hyperactive/impulsive or inattentive symptoms that caused impairment were present before age 7 |
| Some impairment from symptoms is present in ≥2 settings (such as at school, work, or home) |
| Symptoms do not occur exclusively during the course of a pervasive developmental disorder, schizophrenia, or other psychotic disorder and are not better accounted for by another mental disorder (mood disorder, anxiety disorder, dissociative disorder, or a personality disorder) |
| Source: DSM-IV-TR |