It is impossible to underestimate the extent to which bipolar disorder affects the family members and caregivers of our patients.
First of all, bipolar disorder has a strong genetic component. Up to 67% of children with at least one affected parent will go on to develop an affective disorder (Bipolar Disord. 2001;3:325-34 and Bipolar Disord. 2006;8:710-20). In bipolar disorder, multiple neurotransmitter systems as well as the limbic corticostriatal systems are dysfunctional. The dysfunction of the latter is manifested by increased activity in the amygdala and decreased activity in frontal cortical regions (Annu. Rev. Clin. Psychol. 2006;199-235), which might impair the brain’s capacity to regulate emotion. The extremely high prevalence of affective disorders in the children of affected parents might be attributable to this dysfunction.
Second, bipolar disorder affects the family members and caregivers of patients through the family environment. About 90% of family members of patients with bipolar disorder experience subjective burden (for example, feelings of emotional distress) that correlates with the severity of the patient’s illness symptoms (Bipolar Disord. 2007;9:262-73). Family members with higher subjective burden are less likely to practice appropriate health behaviors and, as a result, are in poorer physical health than are family members of patients without mental illness. Higher levels of caregiver burden also are also associated with more emotion-focused coping and lower mastery among caregivers of patients with bipolar disorder (J. Nerv. Ment. Dis. 2008;196:484-91).
Because of this high subjective burden and to other factors such as objective (financial) burden, stigma, and turmoil in bipolar families, family members of patients with bipolar disorder exhibit high rates of depression, anxiety, and other psychiatric symptoms. In fact, caring for relatives with bipolar disorder doubles the risk of recurrence of a major depressive episode in those with a preexisting diagnosis of major depressive disorder.
Additionally, since these depressed or anxious family members usually appear in psychiatrists’ offices in their caregiver roles for their relatives with bipolar disorder, their psychiatric disability is often either unappreciated or unnoticed by clinicians (Bipolar Disord. 2010;12:627-37).
This is unfortunate, because rates of psychiatric disability in family members of patients with bipolar disorder are high (J. Affect. Disord. 2010;121:10-21). Specifically, up to 40% of caregivers qualify for more than one current psychiatric diagnosis, while 60%-80% had at least one lifetime psychiatric diagnosis. Of note, nonbiological relatives had substantially higher rates of psychiatric disability than did biological relatives, indicating that partners of patients with bipolar disorder were more likely to have a familial mental illness themselves. This indicates that patients with bipolar disorder might tend to choose partners who also suffer from mental illness, a pattern known as assortative mating.
Most of the psychiatric diagnoses in caregivers reflect high levels of mood and anxiety symptoms. Depending on the study populations selected, 30%-40% of primary caregivers reported significant depressive symptoms or qualified for a mood disorder (Bipolar Disord. 2005;7:126-36 and Fam. Process 2002;41:645-57). Most of those diagnoses were major depressive disorder (69%), while 20% of caregivers qualified for a diagnosis on the bipolar spectrum (J. Affect. Disord. 2010;121:10-21).
The severity of depression in family members or caregivers might be related to either or both bipolar disorder severity and the stigma associated with it. In other words, family members’ moods might fluctuate with that of the patient; they might be more depressed during acute episodes and find that their depression lifts between episodes.
Finally, 40%-60% of caregivers qualify for a diagnosis of generalized anxiety disorder; as with depression, the nonbiological relatives were more symptomatic than were the blood relatives, lending support to the theory of assortative mating.
Just as mood symptoms of bipolar disorder influence depression and anxiety levels in the family members of patients, the reverse is also true, and the symptom load in caregivers affects the course and the outcome of the illness in their relatives with bipolar disorder. Subjective burden and/or depression compromise caregivers’ ability to effectively manage the demands associated with caregiving, which in turn leads to less favorable patient outcomes. Some of this process is mediated by the increased stress level in the family, which in turn is a reflection of high expressed emotion (EE) (Br. J. Psychiatry 1972;121:241-58). High EE refers to high levels of criticism, hostility, and emotional overinvolvement from a caregiving family member during or immediately after a patient’s acute episode of illness. Patients with bipolar disorder who return to high-EE families after an acute episode are two to three times more likely to relapse in the subsequent 9 months than are patients who return to low-EE families.