Does Temperament Affect Bipolar Treatment Adherence?

Current medication regimens used in bipolar I disorder produce suboptimal patient outcomes more often than not.

Manic or depressive episode recurrence has been estimated at 37% within 1 year of treatment initiation, rising to 60% within 2 years. Lithium, the “gold standard” for bipolar disorder treatment, yields significant symptom control in only 50% to 60% of patients.

Nonadherence to lithium treatment may be a major contributing factor, as it has been estimated as high as 60%. This treatment nonadherence increases the likelihood of manic or depressive episode recurrence and also predisposes patients to become resistant to medications that have worked well for them in the past.

The July 2015 issue of the Nordic Journal of Psychiatry examined the impact of temperament, a patient’s habitual inclination or mode of emotional response, on treatment adherence in euthymic bipolar I.

The investigators employed the Structured Clinical Interview for DSM-IV Axis I Disorders to identify a total of 80 bipolar I patients. They assessed affective temperament using a self-rated instrument that measures 5 variations of it: dysthymic, cyclothymic, hyperthimic, irritable, and anxious.

Using the Morisky Medication Adherence scale, the researchers determined patients’ adherence and categorized it as poor, moderate, or high. Those considered poorly or moderately adherent were grouped as treatment nonadherent.

Overall, 67.5% of bipolar I patients were nonadherent to treatment. Twenty-six patients were considered adherent to treatment, while 54 were deemed nonadherent.

Adherent and nonadherent patients differed significantly in cyclothymic and anxious temperament scores, with nonadherent patients tending to have more mood swings, irritability, and anxiety.

These results suggest that health care providers should take precautions when bipolar I patients with cyclothymic and anxious temperaments are under their care, because these patients need more support to maintain adequate medication adherence.

In the meantime, more study is needed to elucidate the role of temperament in bipolar I disease progression, such as determining whether temperament directly influences the course of disease, or does so through its impact on treatment adherence.