More childhood onset bipolar disorder in the United States than Canada or Europe: Implications for treatment and prevention

Evidence of a high or increasing incidence of childhood onset bipolar disorder in the United States (US) has been viewed skeptically. Here we review evidence that childhood onsets of bipolar disorder are more common in the US than in Europe, treatment delays are longer, and illness course is more adverse and difficult. Epidemiological data and studies of offspring at high risk also support these findings. In our cohort of outpatients with bipolar disorder, two of the major vulnerability factors for early onset - genetics and environmental adversity in childhood - were also greater in the US than in Europe. An increased familial loading for multiple psychiatric disorders was apparent in 4 generations of the family members of the patients from the US, and that familial burden was linked to early onset bipolar disorder. Since both early onset and treatment delay are risk factors for a poor outcome in adulthood, new clinical, research, and public health initiatives are needed to begin to address and ameliorate this ongoing and potentially devastating clinical situation.

Illnesses in siblings of US patients with bipolar disorder relate to multigenerational family history and patients severity of illness

BACKGROUND

Patients with bipolar disorder from the US have more early-onset illness and a greater familial loading for psychiatric problems than those from the Netherlands or Germany (abbreviated here as Europe). We hypothesized that these regional differences in illness burden would extend to the patients siblings.

METHODS

Outpatients with bipolar disorder gave consent for participation in a treatment outcome network and for filling out detailed questionnaires. This included a family history of unipolar depression, bipolar disorder, suicide attempt, alcohol abuse/dependence, drug abuse/dependence, and "other" illness elicited for the patients' grandparents, parents, spouses, offspring, and siblings. Problems in the siblings were examined as a function of parental and grandparental problems and the patients' adverse illness characteristics or poor prognosis factors (PPFs).

RESULTS

Each problem in the siblings was significantly (p<0.001) more prevalent in those from the US than in those from Europe. In the US, problems in the parents and grandparents were almost uniformly associated with the same problems in the siblings, and sibling problems were related to the number of PPFs observed in the patients.

LIMITATIONS

Family history was based on patient report.

CONCLUSIONS

Increased familial loading for psychiatric problems extends through 4 generations of patients with bipolar disorder from the US compared to Europe, and appears to "breed true" into the siblings of the patients. In addition to early onset, a variety of PPFs are associated with the burden of psychiatric problems in the patients' siblings and offspring. Greater attention to the multigenerational prevalence of illness in patients from the US is indicated.

More illness in offspring of bipolar patients from the U.S. compared to Europe

BACKGROUND

Evidence suggests that patients with bipolar disorder from the United States have an earlier age of onset and a more difficult course of illness than those from Germany and the Netherlands. These characteristics were related to a greater family burden of psychiatric illness and the experience of more psychosocial adversity in childhood. We hypothesized that this greater illness burden would extend to the offspring of the US patients.

METHODS

968 outpatients (average age 41) with bipolar illness gave informed consent for participation in a treatment outcome network and filled out a detailed questionnaire about their illness and family history of illness, including whether their offspring had a diagnosis of depression, bipolar disorder, alcohol or substance abuse, suicide attempt or "other" illness. Of those with children, 356 were from the US and 132 were from Europe.

RESULTS

Compared to the Europeans, offspring of patients from the US had significantly (p<0.001) more depression, bipolar disorder, drug abuse, and "other" illnesses. The number of illnesses in the offspring was related to the bipolar parent being from the US, having had childhood adversity, more than 20 prior episodes, and more parental psychiatric illness.

CONCLUSIONS

While the findings are limited by their basis on self report, the distribution of the percentages in the US offspring are similar to those of Axelson et al. (2015) who used direct interviews. The higher burden of illness in the offspring and their in direct progenitors from the US compared to Europe warrant new attempts at better treatment and prevention.

Multigenerational Positive Family History of Psychiatric Disorders Is Associated With a Poor Prognosis in Bipolar Disorder

The authors assessed how family history loading affected the course of illness in patients from the United States. A total of 676 outpatients with bipolar disorder from the United States rated their illness and provided a parental and grandparental history of mood disorder, substance abuse, and other clinical conditions. A positive family history for each illness was associated with almost all of the seven poor prognosis factors established in the study (abuse in childhood, early onset, anxiety and substance abuse comorbidity, rapid cycling, multiple episodes, and worsening of severity or frequency of episodes). Family history for psychiatric difficulties in parents and grandparents was associated with a more complex and difficult course of bipolar illness.

More pernicious course of bipolar disorder in the United States than in many European countries: implications for policy and treatment

BACKGROUND

There is some controversy but growing evidence that childhood onset bipolar disorder may be more prevalent and run a more difficult course in the United States than some European countries.

METHODS

We update and synthesize course of illness data from more than 960 outpatients with bipolar disorder (average age 40) from 4 sites in the U.S. and 3 sites in Netherlands and Germany. After giving informed consent, patients reported on parental history, childhood and lifetime stressors, comorbidities, and illness characteristics.

RESULTS

Almost all aspects of bipolar disorder were more adverse in patients from the US compared with Europe, including a significantly higher prevalence of: bipolar disorder in one parent and a mood disorder in both parents; childhood verbal, physical, or sexual abuse; stressors in the year prior to illness onset and the last episode; childhood onsets of bipolar illness; delay to first treatment; anxiety disorder, substance abuse, and medical comorbidity; mood episodes and rapid cycling; and nonresponse to prospective naturalistic treatment.

LIMITATIONS

Selection bias in the recruit of patients cannot be ruled out, but convergent data in the literature suggest that this does not account for the findings. Potential mechanisms for the early onset and more adverse course in the U.S. have not been adequately delineated and require further investigation.

CONCLUSIONS

The data suggest the need for earlier and more effective long-term treatment intervention in an attempt to ameliorate this adverse course and its associated heavy burden of psychiatric and medical morbidity.

A systematic review of gender-specific rates of unipolar and bipolar disorders in community studies of pre-pubertal children

OBJECTIVES

Gender-specific rates of unipolar and bipolar disorders are well established for cases with post-pubertal onset. However, there is less certainty about these rates in pre-pubertal children. We undertook a systematic review of community studies that report gender-specific rates for unipolar and bipolar disorders in young children, particularly cases of major depression and mania.

METHOD

Computer databases (Medline, EMBASE, Index to Theses, and PsychInfo) were searched for non-clinical observational studies using recognized diagnostic criteria to identify unipolar and bipolar disorders in children aged ≤ 12 years. A meta-analysis was undertaken to calculate pooled odds ratios (ORs) for caseness for major depression by gender. The limited data on bipolar disorder were summarized.

RESULTS

Analysis of 12 studies (>15,000 children), indicated that the community prevalence of unipolar disorders was higher in boys (1.3%) than in girls (0.8%). Rates of major depression were low (0.61%), but boys were significantly more likely to meet diagnostic criteria than girls (OR = 1.61; 95% confidence interval: 1.11-2.35). Five studies, assessing >5,000 children, identified only one case with a probable diagnosis of mania.

CONCLUSIONS

This systematic review suggests that boys aged ≤ 12 years are significantly more likely to experience major depression than girls. However, in younger children, community rates of major depression are low, and it is frequently suggested (but not proven) that most cases are comorbid. The absence of mania suggests either that childhood bipolar phenotypes do not resemble post-pubertal onset cases or that there are problems of case ascertainment.

More stressors prior to and during the course of bipolar illness in patients from the United States compared with the Netherlands and Germany

Considerable data suggest that compared to some European countries, in the U.S. there are more childhood onset bipolar disorders, more adverse courses of illness, and greater treatment resistance. Psychosocial variables related to these findings have not been adequately explored. Therefore we analyzed psychosocial stressors in three time domains: childhood; the year prior to illness Onset; and the Last Episode from questionnaires in 968 outpatients (mean age 41) with bipolar I or II disorder; 676 from four sites in the U.S. and 292 from three in the Netherlands and Germany (abbreviated here as Europe). Compared to the Europeans, those from the U.S. had significantly more stressors in childhood and prior to the last episode. Stressors prior to the last episode were related to: childhood stressors; an earlier age at illness onset; anxiety and substance abuse comorbidity; lower income; both parents having an affective illness; and feeling more stigma. These data suggest a greater prevalence of adverse life events in childhood and over the course of bipolar illness in the U.S. compared to the Netherlands and Germany. Clinical, therapeutic, and public health approaches to these illness-relevant stressors require further exploration.

Neurobiological correlates of illness progression in the recurrent affective disorders

Some clinical aspects of affective illness progression, such as episode-, stress-, and substance-induced sensitization, have been well documented in the literature, but others have received less attention. These include cognitive deficits, treatment-refractoriness, and neurobiological correlates of illness progression, which are the primary focus of this paper. We review the evidence that cognitive dysfunction, treatment resistance, medical comorbidities, and neurobiological abnormalities increase as a function of the number of prior episodes or duration of illness in the recurrent unipolar and bipolar disorders. Substantial evidence supports the view that cognitive dysfunction and vulnerability to a diagnosis of dementia in old age increases as a function of number of prior mood episodes as does non-response to many therapeutic interventions as well as naturalistic treatment. Neurobiological abnormalities that correlate with the number of mood episodes or duration of illness include: anatomical, functional, and biochemical deficits in the prefrontal cortex and hippocampus, as well as amygdala hyperactivity and cortisol hyper-secretion. Some neurotrophic factors and inflammatory markers may also change with greater illness burden. Causality cannot be inferred from these correlative relationships. Nonetheless, given the potentially grave consequences of episode recurrence and progression for morbidity and treatment non-responsiveness, it is clinically wise to assume episodes are causing some of the progressive cognitive and neurobiological abnormalities. As such, earlier and more sustained long-term prophylaxis to attempt to reduce these adverse outcomes is indicated.