CLINICAL DESCRIPTION

DSM-5 breaks out bipolar and related disorders into their own chapter (American Psychiatric Association 2013). The DSM-5 criteria for bipolar disorders are the same for children and adults with a few exceptions: cyclothymic disorder (the required duration is 1 year instead of 2 years) and major depressive episode (in children and adolescents, irritable mood can be substituted for depressed mood, and in children, lack of expected weight gain can qualify instead of weight loss).

In the past three decades, the diagnosis of bipolar disorder in children was a focus of significant scrutiny and controversy as some researchers postulated that bipolar disorder manifested differently in children than in adults. They asserted that children presented with a “broad phenotype” of bipolar disorder marked by ultra-rapid-cycling or sustained mixed episodes, chronic irritability, and explosive outbursts. Subsequent research at the National Institute of Mental Health has since suggested that this group of children represents a different clinical entity and that these children do not progress to develop classic or narrow-phenotype bipolar disorder in adulthood. Disruptive mood dysregulation disorder (DMDD), introduced in DSM-5, was designed to capture this population. The intent was that only children for whom the strict application of diagnostic symptom criteria (i.e., present with discrete manic or hypomanic episodes of sufficient duration that are a clear departure from their baseline functioning and mood) is met should be assigned a diagnosis of bipolar type I or bipolar type II disorder.

EPIDEMIOLOGY

Bipolar disorder in children is extremely rare. Mania is rare before middle adolescence but by late adolescence is nearly as common as in adults. A community survey of high school students found a lifetime prevalence of 1% for all bipolar disorders. An additional 5.7% of the sample had persistent subthreshold hypomanic and associated symptoms (Lewinsohn et al. 1995). In one study, 45% of children and adolescents diagnosed with DSM-IV-TR bipolar disorder not otherwise specified converted to bipolar type I and type II over 5 years (Axelson et al. 2011). Family history of mania or hypomania was the strongest predictor of conversion. Approximately 20% of all patients with bipolar disorder have their first episode during adolescence.

ETIOLOGY

Biological and genetic factors play a large role in the etiology of bipolar disorder. More than one third of first-degree relatives of individuals with bipolar spectrum disorder have symptoms that meet criteria for a bipolar spectrum disorder. Twin studies also demonstrate significant heritability for the disorder (Althoff et al. 2005). In addition, schizophrenia and bipolar disorder likely share genetic contributions (Lichtenstein et al. 2009), and relatives of individuals with schizophrenia have a higher risk of developing either bipolar disorder or schizophrenia. However, environmental factors such as physical and sexual abuse, negative parenting styles, poor social supports, and prenatal alcohol exposure may influence development of the disorder.

COURSE AND PROGNOSIS

Mania and hypomania occurring before adulthood are often misdiagnosed or not recognized. Heedless risk taking, highly energized affect, and developmentally inappropriate sexual preoccupation and behavior are useful markers for mania. Precocious sexuality in a child with manic symptoms should not be presumed to be evidence of sexual abuse. Grandiosity is expressed in different ways than in adults, but the experienced clinician can distinguish these beliefs from normal bragging or childhood fantasy (Geller et al. 2002b). Manic or hypomanic decreased need for sleep must be differentiated from insomnia, resistance to bedtime, or substance use. Family history and longitudinal course may provide important clues. Childhood-onset bipolar disorder carries a worse prognosis than bipolar disorder of adult onset. There is frequent comorbidity with anxiety disorders (62.9%), behavior disorders (attention-deficit/hyperactivity disorder [ADHD], intermittent explosive disorder, oppositional defiant disorder [ODD], conduct disorder) (44.8%), and substance use disorders (36.6%) (Merikangas et al. 2011).

Prospective studies of adolescents and longitudinal studies of children of parents with bipolar disorder suggest that anxiety disorders may be an early manifestation in individuals who subsequently develop bipolar disorder (Duffy et al. 2007; Henin et al. 2005; Lewinsohn et al. 2002).

EVALUATION AND DIFFERENTIAL DIAGNOSIS

Both mania and agitated depression may be confused with ADHD, but mood disorders are typically episodic, whereas ADHD is a chronic condition with onset in early childhood. Symptoms of bipolar disorder that best discriminate from ADHD are elation, grandiosity, flight of ideas/racing thoughts, decreased need for sleep, and hypersexuality (Geller et al. 2002a). Mania in childhood and adolescence is frequently misdiagnosed as schizophrenia because the initial manic episode can include psychotic symptoms. Manic or depressed youth may have some symptoms of ODD or conduct disorder that are secondary to their mood symptoms. Of course, disruptive behavior disorder may precede bipolar disorder or develop in parallel. Secondary mania may result from prescribed medication (e.g., steroids, carbamazepine, antidepressants, stimulants), illegal drugs (e.g., cocaine, amphetamines), metabolic abnormalities (especially hyperthyroidism), or central nervous system disturbances (e.g., tumor, trauma, multiple sclerosis, epilepsy, infections). Of note, DSM-5 allows for a manic episode or hypomanic episode to be diagnosed if the episode emerges in the context of antidepressant treatment as long as the full syndrome persists beyond the physiological effects of the treatment. This should be distinguished from a medication-related side effect of sleeplessness, agitation, or irritability that desists after cessation of the medication.

Bipolar disorder is frequently comorbid with ADHD, ODD, conduct disorder, substance and alcohol use disorders, and anxiety, but teasing apart the distinct diagnoses can be challenging during an acute manic episode.

TREATMENT

It is extremely difficult to implement controlled trials in youth with bipolar disorder. Attempts have been made to extrapolate from research on adults, but the findings are not consistent. All of the mood-stabilizing medications have significant side effects. Drugs with current U.S. Food and Drug Administration indications for pediatric bipolar disorder/mania are lithium (age 12 years and older); the atypical antipsychotics aripiprazole, risperidone, asenapine, and quetiapine (age 10 years and older); and olanzapine (age 13 years and older; other drugs should be considered first because of weight gain). Aripiprazole and lithium have approved indications for prevention of recurrence of mania. Compared with adults, youth with mania have greater response to the atypical antipsychotics, but youth experience lower effect sizes with the mood stabilizers divalproex and lithium. In a direct comparison in youth with bipolar disorder, risperidone was faster and more effective than divalproex in acutely reducing symptoms of mania (Pavuluri et al. 2010). The Treatment of Early Age Mania (TEAM) study (Geller et al. 2012) found risperidone to be superior to both divalproex and lithium.

In contrast to the usual preference for monotherapy in pediatric psychopharmacology, combinations of medications are often needed for mania. Efficacy in bipolar depression remains elusive. Because of the risk of precipitating mania, antidepressants are generally not used in bipolar depression until treatment with a mood stabilizer is established. See Chapter 17 (“Psychopharmacology”) for information on the use of lithium, antipsychotic medications, and anticonvulsants.

There are multiple empirically supported psychosocial interventions to be added to medication treatment, especially for adolescents. Models include Family-Focused Treatment for Adolescents (FFT-A) (Miklowitz et al. 2008), family psychoeducation, child- and family-focused cognitive-behavioral therapy, and others (Weinstein et al. 2013).