by David Feifel, MD, PhD
Dr. Feifel is Associate Professor in Residence, Department of Psychiatry; Director, Neuropsychiatry and Behavioral Medicine Program; Director, UCSD Adult ADHD Program, University of California, San Diego Medical Center, San Diego, California.
Disclosures
Dr. Feifel has received research funding, consulting, or speaking fees from the following pharmaceutical companies: Abbott Laboratories, AstraZeneca, Argolyn Biosciences, Eli Lilly and Co., Bristol-Myers Squibb, Solvay, Janssen, Wyeth, Macneil, and Shire.
Print Citation
Psychiatry (Edgemont) 2007;4(12):60-62
A good cartoon can sometimes capture a complex phenomenon with simplicity and humor. One of my favorite cartoons shows a patient stripped to his boxer shorts standing in a physician’s examination room. Behind the patient is an enormous rhinoceros thrusting its horn into the patient’s flank. The physician is pensively standing back, taking in the scene before him with one hand on his chin. The caption reads “Mr. Grimbly, I think it may not be kidney stones after all.” Implicit in this scene is a preceding situation in which the physician assumed the patient’s unilateral flank pain was due to kidney stones. Presumably, it was only when the patient’s pain did not respond to conventional treatment for kidney stones that the physician finally stepped back and recognized what would seem to be obvious—that a rhinoceros was the source of the flank pain. I am fond of this particular cartoon because it captures a common phenomenon in psychiatry that is encountered by anyone who works with adult patients that have attention deficit hyperactivity disorder (ADHD). However, instead of flank pain, the presenting condition is depression and/or anxiety.
Just as a primary care physician is likely to immediately think “kidney stones” when confronted with complaints of sharp unilateral flank pain, psychiatrists are trained to immediately think “clinical depression” or “generalized anxiety disorder” when a patient presents with features of either of these conditions. However, it is important to recognize that ADHD may sometimes be the rhinoceros behind features of clinical depression or anxiety in an adult. Whereas a rhinoceros as an etiology for a chronic medical condition is an absurdly rare phenomenon, adult ADHD is most definitely not. Approximately 4.5 percent of the adult population suffer from ADHD.1 Furthermore, it is well recognized that adults with ADHD have high rates of depression and anxiety.[1] Perhaps more relevant to the average physician is the high prevalence of ADHD among patients recognized as having depression or anxiety. One third of adults with ADHD have a depressive disorder (major depression or dysthymia) and approximately one in eight have generalized anxiety disorder.[1]
The common term used to describe the concurrent existence of additional psychiatric condition(s) is comorbidity. However, describing depression or anxiety in a patient with ADHD as a comorbid condition is often misleading. While they may have similar environmental or genetic etiologies, comorbid conditions are nevertheless usually independent conditions that exist concurrently in a patient. In contrast, depression and anxiety features that occur in patients with ADHD frequently are a direct result of the ADHD and continue to exist only by virtue of untreated symptoms of ADHD. This is a relationship between disorders similar to a parasite-host relationship, in which the parasite depends on a host organism for its existence and continued survival. Thus, rather than comorbidity, a more accurate term perhaps to describe situations of depression or anxiety features occurring in a patient with ADHD might be parisito-morbidity.
When people experience the chronic underachievement that characterizes ADHD for long periods of time, they have an increased likelihood of becoming despondent and demoralized. This is best understood by the famous “learned helplessness” model of depression made famous by the psychologist Martin Seligman,[2] who observed that animals exposed to unavoidable painful stimuli eventually stop attempting to escape the stimuli and exhibit a psychomotor retardation, suggesting they have become reconciled to their circumstance.
An analogous situation may arise in adult patients with ADHD. Sometimes anxiety rather than depression is the more prominent consequence in ADHD adults. In both cases, the depression or anxiety is generated and sustained by the impairment caused by the ADHD. This parisito-morbid relationship, if recognized, affords the potential to eliminate both conditions by effectively treating the “host” condition—the ADHD. On the other hand, a failure to recognize an ADHD rhinoceros can lead to prolonged suffering in patients and frustrating trials of treatment for depression or anxiety with limited benefit. Thus, it is very important to screen for ADHD in all patients presenting with depression or anxiety.
If ADHD is found to exist in a depressed or anxious patient, the next step is to attempt to elucidate whether the depression and/or anxiety is comorbid or parisito-morbid with the ADHD. Patients with depression that is parisito-morbid to ADHD often, when asked, do not express the global existential features of major depression, but rather feel that if their frustrated attempts to accomplish certain goals were met with a degree of success commensurate with their innate abilities (e.g., intelligence) and the effort they are putting forth, they would not feel depressed.
Sometimes this can become apparent by asking a few well selected questions. For example, “If you did not have the difficulty you are experiencing (keeping a job, succeeding in school, passing your board exams, etc.), do you think you would still feel as depressed as you do now?”
For patients who present with anxiety and ADHD, inquiring about the content of their anxious feeling can help distinguish comorbid and parisito-morbid anxiety. People suffering from a bona-fide generalized anxiety disorder worry about a number of distinct bad events and do so out of proportion to the realistic likelihood of that bad outcome occurring. They are often known by others to be general “worry-worts” by nature. In contrast, people whose anxiety is derived from their ADHD tend not to be generalized worriers and may be quite positive in outlook on the whole, but will have fairly circumscribed worry directed at some productivity demand placed upon them (e.g., school, work, etc.). Rather than an unrealistic worry, their apprehension stems from an implicit or explicit awareness of their ADHD-related limitations. The student with ADHD will become anxious about school, the employee about work. Furthermore, episodes of anxiety will commonly arise at times of increased demand or expectations (e.g., following a promotion).
The above described clinical clues that features of depression or anxiety in a patient is in fact parisito-morbid of untreated ADHD should lead clinicians to considering focusing on treating the underlying ADHD first and foremost. In fact even when it is not clear whether depression or anxiety in a patient with ADHD is comorbid (i.e., independent) or parisito-morbid, there are good reasons to focus treatment on the ADHD first. Treatments for ADHD are generally more efficacious, robust, and rapid than treatments for depression or anxiety. Therefore, a strategy for treating the ADHD first is likely to yield an empirical answer to the question as to whether the coexisting depression or anxiety emanates from the ADHD or is self-sustaining in its own right. The one exception to an ADHD-first approach may be when a depression is associated with substantial suicidal risk. In such cases, treatment for depression cannot be delayed.
In summary, ADHD is a highly prevalent condition in adults, but many psychiatrists are not yet as facile at recognizing its existence as they are at recognizing depression and anxiety. Because ADHD in an adult can frequently be a host condition for other psychiatric symptoms, such as depression and anxiety, clinicians need to develop the routine practice of screening for ADHD in all patients who present with features of anxiety and depression. When identifying and recognizing ADHD coexisting with depression or anxiety features, a clinician should attempt to determine whether the depression or anxiety are likely to be independent of or generated and sustained by the ADHD (comorbid vs. parisito-morbid). When evidence suggests the latter case or when it is not clear, there is good reason to aggressively treat the ADHD first, as often successful treatment of the ADHD will resolve or greatly reduce the depression or anxiety.
References
1. Kessler RC, Adler L, Barkley R, et al. The prevalence and correlates of adult ADHD in the United States: Results from the National Comorbidity Survey Replication. Am J Psychiatry 2006;163:716–23.
2. Seligman MEP, Maier SF. Failure to escape traumatic shock. J Exp Psychol 1967;74:1–9.
