Treating Bipolar Disorder in Primary Care

Psychiatrists practicing integrated behavioral health care are increasingly being asked to advise and assist in the treatment of patients with bipolar disorder. Joseph Cerimele, M.D., M.P.H., is an integrated care psychiatrist with a special interest in bipolar disorder, and in this month’s column, he provides a timely overview of the treatment of bipolar disorder in primary care. —Jürgen Unützer, M.D., M.P.H.

Bipolar disorder has historically been viewed as a specialist-treated illness, though increasingly many patients with bipolar disorder present to and receive treatment in primary care settings. There are several ways to consider the illness burden of bipolar disorder in primary care settings, including:

• Prevalence compared with that of the general population

• Proportion of patients seeking treatment in primary care

• Clinical characteristics

• Quality of care in primary care

• General medical illness burden

In general, the prevalence of bipolar disorder in primary care settings is approximately twice that of bipolar disorder found in the general population. The National Comorbidity Survey Replication (NCS-R) results estimated the general population prevalence of bipolar I and II disorder at about 1 percent each, and subthreshold bipolar disorder at about 2.4 percent, based on assessments using structured interviews.

In primary care studies, structured interviews of random primary care samples revealed bipolar disorder I or II in up to approximately 4 percent of the patients. Prevalence estimates increased to up to 9 percent when including individuals with bipolar I, bipolar II, or subthreshold bipolar disorder illnesses. Among primary care patients presenting with a psychiatric symptom complaint, up to 10 percent of patients were found to have bipolar disorder on a structured interview.

Another way to look at the bipolar disorder illness burden in primary care is to consider where individuals with bipolar disorder seek care. Results from the NCS-R showed that over their lifetime, almost all patients with bipolar I or II disorder had received treatment from a psychiatrist. However, in the past 12-month period, about the same proportion of people with bipolar I or II disorder sought treatment in primary care settings as those seeking treatment from psychiatrists. Among individuals with subthreshold bipolar disorder, approximately 2.5 times as many people sought treatment in primary care compared with specialty psychiatric care over the last 12 months. Most people received treatment from a psychiatrist at least once during their lifetime, but few have received treatment from a psychiatrist in the past 12 months. It seems over time patients move between receiving treatment in primary care and specialty mental health settings.

Our research on patients with bipolar disorder in Washington state had similar findings. The majority of patients with bipolar disorder in our sample had previously been treated by a psychiatrist, and over one-third of patients had been previously psychiatrically hospitalized, though all were currently seeking treatment in primary care. Furthermore, the patients with bipolar disorder seeking treatment in primary care had a high depression symptom burden, co-occurring problems such as substance use, and significant psychosocial impairment. However, many patients didn’t improve with treatment in primary care.

Quality of care measures such as receipt of appropriate medication treatment and co-occurrence of general medical problems are additional ways to consider the illness burden of patients with bipolar disorder seen in primary care. Research from the Department of Veterans Affairs showed that patients with bipolar disorder treated exclusively in primary care settings were more likely to have co-occurring general medical problems and less likely to receive optimal medication treatment for bipolar disorder. Other studies including the NCS-R have also shown that patients with bipolar disorder treated in primary care settings were less likely to receive mood-stabilizing medication and more likely to receive either no medication treatment or antidepressant medication without mood-stabilizing medication.

General medical illnesses such as diabetes or chronic obstructive pulmonary disease frequently occur in individuals with bipolar disorder and can have significant consequences. Results published in 2013 from Sweden showed that individuals with bipolar disorder had a shortened life span by about nine years compared with individuals without bipolar disorder. Premature mortality was due to chronic illnesses, infections, and accidents/suicide. Notably, however, individuals who had medical problems detected and treated earlier on had a lower risk of mortality, approaching the risk of those without bipolar disorder. Chronic illnesses such as cardiovascular diseases are commonly detected and treated in primary care, suggesting that pairing general medical and bipolar disorder treatments could improve individuals’ overall well-being and health outcomes.

Going forward, we need to think about how psychiatrists can support treating patients with bipolar disorder who seek treatment in primary care. Additionally, patients currently seeking treatment from a psychiatrist may eventually shift care into primary care settings, which underscores the importance of communication with primary care colleagues. Care models supporting treatment of patients with psychiatric illnesses in primary care such as collaborative care may offer other avenues for improving the mental health, and perhaps general health, outcomes of patients with bipolar disorder seen in primary care. ■