In the United States and Europe, the lifetime prevalence of cyclothymic disorder is in the 0.4%-2.5% range, with no apparent gender differences.[2,3] The onset of the disorder is usually in adolescence or early adulthood, as it was in this patient. The likelihood that a patient with cyclothymic disorder will subsequently develop bipolar I or bipolar II disorder is 15%-50%. Thus, the status of mood episodes in this patient should regularly be monitored and not be assumed to be unchanging. The diagnosis of a personality disorder can only be made when the person is aged 18 years or older. Although traits may be present earlier, for the purposes of diagnosis, a personality is considered formed only at age 18 years or older.
A genetic or familial risk for cyclothymic disorder may exist among relatives of persons with bipolar I disorder. On the basis of the description in this patient's family history, it is possible that her father had a prior manic episode, which might qualify him for a diagnosis of bipolar I disorder if the episode was not explained by other medical or substance use contributors. If he does have bipolar I disorder, that may present a predisposition for cyclothymic disorder in this patient.
Other diagnostic considerations for this patient might include these disorders:
Substance/medication-induced bipolar and related disorders
Bipolar disorder due to another medical condition
Substance/medication-induced bipolar and related disorders are distinguished from cyclothymic disorder by the judgment that a substance/medication (especially stimulants) is causally related to the mood symptoms. The frequent mood swings would be expected to resolve after cessation of substance/medication use. High-level athletes are at some risk for misuse of substances, including stimulants and anabolic androgen steroids, for performance enhancement purposes; these substances can contribute to mood swings that may resemble bipolar spectrum illness. In this case, the patient denied illicit drug use or misuse of prescription medications, and her urine toxicology screening results were reassuring. She consumes a fair amount of caffeine, but not to the point that it would cause her episodic mood symptomatology.
In bipolar disorder due to another medical condition, findings from the history, physical examination, or laboratory studies would suggest a general medical cause of the mood symptoms. Thyroid dysfunction and traumatic brain injury (such as in sport-related concussion) are two such possible causes. In this case, there is no evidence of such conditions causing the symptoms.
Borderline personality disorder is associated with brief, recurrent shifts in mood. However, persons with this disorder tend to have mood instability in the form of irritability, anxiety, and sadness, and not elation, euphoria, or increased energy.
Eating disorders are disproportionately common in athletes. In addition, overexercise is not uncommonly part of these disorders, especially in athletes. Although screening for an eating disorder should be performed in this patient, an eating disorder would not explain her mood episodes. Her body mass index, laboratory results, and vital signs are normal (except for very mild bradycardia, which is not uncommon in athletes); these findings are reassuring, though they do not rule out all eating disorders. It is interesting that while experiencing hypomanic symptoms, this patient overexercises to a much greater extent than her baseline high level of exercise. This may explain her history of multiple overuse injuries and current evidence of "shin splints." Figure 2 is an example of a tibial stress fracture that can develop due to overexercise.
Overexercise can occur in bipolar disorder, especially during episodes of hypomania or mania, perhaps as a functional outlet for excess energy, as part of overall increased goal-directed activity, or even consciously or subconsciously to perpetuate the elevated hypomanic/manic mood state. Many things that have antidepressant properties, including exercise and antidepressant medications, may serve to incite or intensify a manic mood state.
This patient mentioned that she feels a baseline state of anxiety on the rare occasions when she is not experiencing hypomanic or depressive symptoms. Further clinical questioning is needed to determine whether these symptoms persist in a way that would meet the criteria for a comorbid anxiety disorder. Insufficient information is given in the vignette to make a determination at this time.
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Cite this: Claudia L. Reardon. A 22-Year-Old Female College Athlete With Wild Mood Swings - Medscape - Jun 17, 2022.