Bipolar disorder and population health

Abstract

Research has shown the majority of individuals with bipolar disorder do not receive treatment from a psychiatrist in a 12 month period. A large proportion of individuals with bipolar disorder in the United States seek treatment in primary care, rather than specialty mental health care, settings. Individuals with bipolar disorder seen in primary care settings have high symptom severity and functional impairment, but are less likely to receive treatment with mood stabilizing medications for bipolar disorder. We have found in clinical practice one-third of patients with bipolar disorder improved after receiving treatment in primary care in a statewide collaborative care program. The collaborative care approach originally developed for treating patients with depression in primary care may need to be strengthened or adapted for treating patients with bipolar disorder. Strategies such as telehealth or enhanced collaborative care also addressing psychosocial needs may be needed to effectively treat the patients with bipolar disorder already seeking treatment in primary care.

Bipolar disorder has a lifetime prevalence of 4.4% of the general population, or approximately 14 million individuals in the United States based on 2015 population estimates (1). The prevalence of bipolar disorder is similar in men and women, and across races and ethnicities (1). Incident bipolar disorder often occurs in late adolescence, providing an opportunity for intervention and sustained management over many years in adulthood. However, detection remains a problem, and of those eventually diagnosed, an average of 6–8 years passes between symptom onset and diagnosis (2). Many individuals with bipolar disorder experience chronic symptoms, and bipolar disorder remains a leading cause of disability in the United States. A significant need exists to improve the health of the population, or entire group, of individuals with bipolar disorder.

What proportion of individuals with bipolar disorder receives treatment?

Findings published in 2007 showed that almost all individuals with bipolar I or II disorder (89% and 95% respectively) received treatment for bipolar disorder at least once during their lifetime, and approximately two-thirds had ever received treatment from a psychiatrist (1). However, the picture is different when looking at receipt of treatment during the past 12 months. Figure 1 illustrates where individuals with bipolar disorder reported receiving treatment in the past 12 months.

Figure 1.

Treatment setting in past 12 months for individuals with bipolar disorder

The proportion of individuals with bipolar I disorder, bipolar II disorder or subthreshold bipolar disorder receiving treatment from a psychiatrist, general medical clinician, or no treatment in the past 12 months

About one-third of individuals with bipolar I or II disorder reported not receiving treatment for bipolar disorder in the past 12 months (1). Individuals who did receive treatment were equally divided into those having received treatment from a psychiatrist and those having received treatment from a general medical clinician such as a primary care clinician (1). An even smaller proportion of people with subthreshold bipolar disorder received treatment. In the past 12-month period, two-thirds of people with subthreshold bipolar disorder reported not receiving any treatment, and only 8% received treatment from a psychiatrist.

Although many patients with bipolar disorder seek care in general medical settings few receive effective medication treatment. Many patients in primary care often receive no medication treatment, or treatment with medications other than mood stabilizing medications such as antidepressant medications (1,3). Antidepressant use in individuals with bipolar disorder remains controversial with effective use in some patients with bipolar II disorder (4). However a recent consensus statement (5) recommended avoiding use of antidepressant medications in individuals with bipolar depression concurrently experiencing two or more manic symptoms, which the STEP-BD study showed occurred in approximately half of patients with bipolar depression (6).

Not receiving effective medication treatment is a significant problem since individuals with bipolar disorder often experience chronic, but treatable, symptoms. Individuals followed for an average of 12 years experienced symptoms approximately half of the weeks during the study period, with depressive symptoms occurring significantly more often than manic or hypomanic symptoms (7). Presence of depressive symptoms is associated with recurrence of a mood episode in individuals with bipolar disorder (8), suggesting that treatment of residual depressive symptoms could reduce the incidence of mood episode recurrence. Individuals with bipolar disorder who have not received treatment, or received ineffective medication treatment over the past 12 months, may have experienced missed opportunities for having treatment adjusted or intensified to manage recurrent or chronic symptoms.

How can a greater proportion receive high quality treatment?

One option for improving the health of individuals with bipolar disorder could be improving the quality and intensity of mental health care in the general medical setting since many patients are only seen in this setting in a 12 month period. Furthermore, office visits resulting in a diagnosis of bipolar disorder increased more rapidly in primary care compared to specialty mental health settings from 1995 to 2010 (9). Medication treatment is usually necessary in providing high quality care to individuals with bipolar disorder and could be offered in primary care settings. Improving patients’ well-being will also require determining how to effectively address the psychosocial needs of patients with bipolar disorder in primary care (10). However there are currently numerous barriers to primary care clinicians prescribing mood stabilizing medications and limited resources to address psychosocial needs in primary care settings.

To understand how to improve the quality of care delivered in primary care, we explored the characteristics of 740 primary care patients with bipolar disorder (11). We found that patients presented with an average symptom burden of moderately-severe depressive symptoms, co-occurring PTSD symptoms, and substance use problems (11). Fifty-seven percent had ever received treatment from a psychiatrist, and one-third of patients had one or more prior psychiatric hospitalizations. Current suicidal ideation was present in over half of the sample, and about 10% reported homelessness (11). This is consistent with prior findings that patients with bipolar disorder in primary care have significant symptom severity, and psychosocial impairment similar to patients seen in mental health settings (12).

Patients in our study were receiving treatment from primary care clinicians assisted by a psychiatrist and a care manager using a collaborative care model intended to treat patients with depression. Collaborative care treatment includes team-based care offering multiple opportunities for patient assessment, symptom measurement, and treatment intensification (guided by a consulting psychiatrist) for patients who are not achieving treatment targets. Despite having treatment supported by a care manager and psychiatrist, and average treatment duration of 30 weeks, we found that 33% of patients in our primary care sample experienced significant clinical improvement (11).

Future directions

Improving the mental health outcomes for the entire population of individuals with bipolar disorder will need to include effectively identifying and treating patients in primary care settings since a significant proportion of patients seek care in such general medical settings. Detecting bipolar disorder using structured screening measures supplemented with additional clinical information may also be applicable to some primary care settings (12, 13). Accurately identifying primary care patients with bipolar disorder could help provide patients with higher quality of care such as treatment with mood stabilizing medications and psychotherpay. For these patients seen only in primary care, it will be important to develop strategies for intensifying treatment when residual depressive or manic symptoms or mood episodes are present.

The collaborative care approach originally developed for treating patients with depression in primary care may need to be strengthened and adapted for treating patients with bipolar disorder. Two options for doing this could be direct consultation with a psychiatrist during initial treatment stages, or direct medication management by a psychiatrist, perhaps using telehealth care technologies to provide high quality treatment in primary care. In addition to initial psychiatric consultation, frequent opportunities for changing or intensifying treatment, including use of psychotherapy, will be necessary to address persistent depressive and other symptoms commonly found in patients with bipolar disorder.