Update on Bipolar Disorder: Epidemiology, Etiology, Diagnosis, and Prognosis

Author: Charles L. Bowden, MD, University of Texas Health Science Center at San Antonio

[Medscape Mental Health 2(6), 1997. © 1997 Medscape, Inc.]

Abstract: Bipolar disorder, or manic-depressive illness, continues to be a diagnostic challenge, even for experienced clinicians. The primary difficulty is differentiating major depression from bipolar disorder, since many patients present during a depressive episode and do not consider their hypomanic or manic episodes part of the disease. A careful history and discussion with significant others such as family members can aid in diagnosis.

Introduction

Expenditures related to affective disorders in the US were an estimated $20.8 billion in 1985, with direct treatment costs comprising 58.4% of the total that year. By 1990, the total associated costs had increased to $30.4 billion.[1] A 1991 report from the National Institutes of Mental Health indicated that previous estimates of bipolar-related expenditures may have been too low, with 1991 total costs for bipolar illness alone estimated at a staggering $45 billion. Direct costs totaling $7 billion consisted of expenditures for treatment-related inpatient and outpatient care, as well as nontreatment-related costs such as use of the criminal justice system. The $38 billion in indirect costs included the lost productivity of wage-earners ($17 billion), homemakers ($3 billion), those who have been institutionalized ($3 billion), individuals who committed suicide ($8 billion), and caregivers of manic-depressive family members ($6 billion).[2]

Given that affective disorders represent 21% of the costs of all mental illnesses,[1] and because bipolar disorder is a particularly recalcitrant mental health problem, research directed at comprehensive strategies to reduce the prevalence of bipolar variants is essential to lessen the suffering of patients and their families, and to ease the economic burden of this illness on limited societal resources. The growing body of research on bipolar disorder has allowed further refinement of symptom classifications and an increase in available therapeutic options, with a trend toward multidrug therapy. The challenge for clinicians is to identify the most appropriate management strategy for a particular patient, a process that is often complicated by comorbid conditions, substance abuse, and noncompliance.

Bipolar disorder is one of the earliest described mental maladies: In 1921, when Kraepelin applied the term manic-depressant insanity to cyclic episodes of mania alternating with depression, the syndrome had already been recognized for over 2000 years.[3] The term bipolar disorder was introduced in the mid-1970s by Kendell in a largely unsuccessful attempt to lessen confusion between this condition and schizophrenia.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-III), published in 1978, was the first to include bipolar disorder as a distinct diagnosis. Revised diagnostic criteria were published in the DSM-III-R in 1987. Further revisions were approved for the DSM-IV, published in 1994.[4]

Yet because misdiagnosis is still common, as many as 2 out of 3 people with bipolar disorder do not receive appropriate treatment.[5]

Lithium (Li) was first used to treat manic episodes in the late 1940s,[6,7] but it was not approved for clinical use in the US until 1970. Despite Li's marked antimanic activity, response to it is inadequate for about half of those with bipolar illness.[8-11] Noncompliance with lithium therapy is a significant problem due to intolerance of adverse effects such as perceived mental sluggishness, thirst, polyuria, and weight gain.[12,13]

These shortcomings have contributed to continued interest in effective alternative therapies for bipolar disorder, most notably the studies that led to the approval by the FDA of divalproex in 1994.

Manifestations of Bipolar Disorder

Bipolar disorder is so named because it is characterized by alternation between states. Yet, it actually is part of a diverse, heterogeneous group of chronic disturbances that produce cyclic episodes of elation or depression, evidenced by varying cognitive and behavioral symptoms. Moreover, the disease can present with significant psychotic features, and there is greater recognition in recent years that most excited psychoses with a biphasic course belong in the bipolar spectrum.[14] Symptoms can vary from episode to episode. There is also variation in degree of polarity, intensity of symptoms, duration of episodes, and rapidity of cycling.

Mania and depression have historically been considered to be polar opposites on a continuum wherein normal mood lies somewhere in the middle. However, manic and depressive symptoms often co-occur in patients, worsening or improving in tandem. Based primarily on intensity of symptoms, manic-depressive illness can be subdivided into 3 categories: (1) a manic episode with or without a previous major depressive episode constitutes bipolar I disorder[4]; (2) depression interspersed with episodes of hypomania constitutes bipolar II disorder; and (3) hypomania cycling with less severe periods of depressive symptoms termed cyclothymia. The mood spectrum is wide, and many patients' manifestations do not fit easily into these 3 discrete categories.

Mania and hypomania. Manic episodes are characterized by an abnormally or persistently elevated, expansive, or irritable mood for at least 1 week, accompanied by at least 3 of the following: inflated self-esteem or grandiosity, decreased sleep, talkativeness, flight of ideas, distractibility, increase in goal-directed activity, or excessive involvement in pleasurable activities that may have painful consequences (DSM-IV). These episodes are usually, but not always, interspersed with periods of depression. Although some patients experience periods of severe mania and depression (bipolar I category), bipolar II illness is nearly as common. The illness course characteristics and functional sequelae of bipolar I and II disorder are quite similar, suggesting that both warrant similarly vigorous treatment.[15] Usually there is a history of a major depressive episode, but with a milder alternate elevated (hypomanic or irritable) state. Many patients do not recognize their hypomanic periods as dysfunctional because they lack subjective distress during the episode.

Depression. The core characteristics of depression are diminished interest, energy, and ability to experience pleasure. This is frequently accompanied by profound pessimism and despair. Symptoms are less variable in the depressed phase, although severity varies widely--both individually and from patient to patient. Irritability, anger, paranoia, emotional turbulence, and anxiety are common. Slowed mental activity, impaired volition, hypochondriacal thinking, retarded or regressive behavior, extreme fatigue, insomnia, and loss of appetite are also common. Excessive sleeping and psychomotor retardation are somewhat more characteristic of bipolar depression than of major depressive disorder.

Mixed mania. Mixed states of simultaneous mania or hypomania and depressive symptoms occur frequently: about 40% of all manic episodes have mixed features. While the mix of symptoms can vary in degree, frequency, and duration, this episode is usually characterized by depressive symptoms in the midst of mania.[14]

Cyclothymia. Cyclothymia is characterized by a pattern of mood swings between hypomania and less severe depression than is typically seen with either bipolar I or bipolar II patterns. At least one third of patients with this symptom pattern go on to develop full-blown bipolar disease after several years; many have a family history of bipolar disorder.

Rapid cycling. The 13% to 20% of people with bipolar disorder who within a year experience 4 or more episodes of depression, mania, or hypomania (demarcated by either a switch to the opposite pole or a period of remission) are classified as rapid cyclers. However, only about 20% of those with a rapid-cycling course demonstrate this pattern from the onset of their first episode. It is more common in women classified as bipolar type II. When rapid cycling occurs, the number of episodes, rather than cycles, is counted. As in mixed-state disorders, this pattern appears to be a (transient or chronic) Li-resistant variant of bipolar illness. This group is often helped by other mood stabilizers, which suggests that they may constitute a distinct pathologic subgroup. Antidepressants, especially tricyclic antidepressants (TCAs), may induce rapid cycling in some people with bipolar disorder.

Epidemiology

The significant morbidity and mortality associated with bipolar disorder make it a major public health problem. About 1.6% of the US population has bipolar disease.[16] Its prevalence seems to be rising. The recognized incidence is probably an underestimate because of underreporting and underrecognition of manic and hypomanic episodes. Bipolar II and cyclothymia prevalence rates are low because most studies have included only bipolar I disorder. Even when bipolar II patterns are included, the difficulty of establishing a history of hypomanic episodes leads to underdiagnosis. Assessing cyclothymia is even more difficult.

Risk factors. The lifetime risk in most countries is reported as 1% to 1.5%, and is probably around 2% when bipolar II symptomatology is included. A recent study of 38,000 community subjects from 10 countries showed striking cross-national similarities in the epidemiology of bipolar disorder. The study conducted in the US, Canada, Puerto Rico, France, Germany, Italy, Lebanon, Taiwan, Korea, and New Zealand found the mean age at onset to be approximately 25 to 35 years in each country. It confirmed the lack of a gender difference in incidence of bipolar disorder, and the earlier age of onset of bipolar disorder than of major depression.[17]

There is no apparent gender difference in incidence of bipolar disorder, but hormonal factors may account for gender differences in the clinical course of illness (eg, higher rates of rapid cycling among women) and deserve further study.[18]

There is strong evidence for an inherited predisposition to bipolar disorder in most patients. Nearly two thirds have a positive family history of affective illness.[19] If 1 parent has a major affective illness, the risk to the offspring has been found to be 25% to 30%.[20] If 2 parents have affective illness and one is bipolar, the risk of affective illness in the offspring may be as high as 50% to 75%.[21] The risk is even greater if there is an extensive multigenerational history of bipolar illness. Relatives of people with bipolar illness frequently have unipolar illness and substance abuse disorders.[20]

Episodes are seasonal in some persons, with depression being more common during spring (March through May) and autumn (September through November), and manic episodes being more likely during the summer.[22] The autumn onset of depression was supported by results of a study comparing relapse patterns among bipolar I patients in northern and southern hemispheres.[23] Suicide attempts have generally been reported to coincide with depressive and mixed manic episodes, peaking in spring and, to a smaller degree, in October. A biological link between depressive episodes and mixed manic episodes in bipolar disorder is the high frequency of elevated cortisol levels, in contrast to normal levels in elated, or pure, mania.[24,25]

First occurrences are more likely before age 30, and recurrences are the rule.[26] Adolescence through the early 20s is the peak age of onset: about 25% of first episodes occur before age 20. The earlier the onset, the greater the likelihood of psychotic symptoms and the more obvious the genetic link.

Prognosis

Bipolar disorder persists for life, with a cumulative debilitating impact on patients' lives and relationships. Ongoing illness can sometimes be indistinguishable from the social or occupational consequences of either mania or depression. Long-term studies of the course of manic-depressive illness have had many methodological limitations, which make straightforward conclusions difficult to reach. One problem is that the diagnosis and selection of patients differ across the various studies; another is that different definitions for recovery and relapse have been used. Most studies have been retrospective rather than prospective.

Factors that have been associated with a less favorable illness course in more than one controlled study include presence of psychosis, a concurrent substance abuse disorder, a greater lifetime number of illness episodes (possibly as few as 3 confers poor prognosis), bipolar disorder secondary to general medical conditions, and mixed and rapid cycling.[27,28]

In a recent survey of members of the National Depressive and Manic-Depressive Association (DMDA) who have bipolar disorder, 59% had their first symptoms during childhood or adolescence, and 45% of respondents said that they experience "frequent" recurrences. Childhood or adolescent onset was associated with frequent recurrence. Both early onset and frequent recurrence were associated with increased social morbidity.[5] In light of its chronic and relapsing nature, the disorder remains a significant public health problem.

Mortality. The mortality rate for untreated manic-depressive illness is higher than that for most types of heart disease and some types of cancer. The risk of suicide is high in this population: about 15% to 25% of people with untreated or inadequately treated (ie, symptomatic) bipolar illness attempt suicide.[29] Although a greater proportion of women attempt suicide, there is no gender difference among those who succeed. Attempts are more common during the first episode, but become increasingly serious with subsequent episodes. Suicidal intent is usually communicated to others. Unfortunately, most people who attempt suicide have recently seen a physician, but few have been correctly diagnosed and treated appropriately.

Etiology

The genetic predisposition to bipolar disorder suggests a biological etiology. Researchers seeking to confirm a biochemical basis have focused on diverse neurotransmitter systems and their interactions, neuroendocrine abnormalities,[30] neuropeptides, electrolytes, and, most recently, membrane transport systems. Small samples and the difficulty of clinical implementation have limited the utility of these findings. Several studies do indicate greater noradrenergic activity during manic than depressive illness episodes, and a specific link of noradrenergic dysfunction to bipolar disorder,[31] not major depressive disorder has been identified.[21,32] Recent reports of reduced levels of key substances involved in intraneuronal signal transduction (protein kinase C, marcks protein) have the potential to link biochemistry to improved pharmacotherapy for bipolar disorder. Recently published structural neuroimaging studies in mood disorders suggest that a smaller frontal lobe, cerebellum, caudate, and putamen appear present in unipolar depression, whereas a larger third ventricle but smaller cerebellum and temporal lobe appear present in bipolar disorder. The most recent studies of intracellular signaling systems and brain structure and function continue to have the serious limitation of small samples that may be atypical.[33]

Other medical causes. Manic and hypomanic symptoms can reflect neuropathologies, infections, metabolic disturbances, and other conditions, including drug effects.[34,35] Reversible causes of bipolar disorder should always be considered when evaluating symptomatic patients. The term secondary mania is applied to bipolar conditions resulting as sequelae to other medical disorders, such as stroke, brain trauma, infections, substance abuse, and metabolic and endocrine disorders.[36] Secondary mania is frequently precipitated by sleep disruption and is not typically associated with family history of mood disturbances.[37] Manic symptoms tend to predominate, and irritability is more common than euphoria. Li is not so effective with secondary mania.[28,38] Recognition of secondary mania is therefore important for planning treatment--an added reason for establishing the presence of comorbidity. Medical problems and drug effects also can underlie depression. It is therefore imperative that a comprehensive assessment consider underlying diseases or drugs that can precipitate manic depression.

Comorbid conditions. If a patient has no family history of affective illness or responds poorly to treatments for bipolar disorder, other medical conditions (such as renal or hepatic dysfunction, thyroid disease, or other metabolic illness, infections, tumors, or seizures) should be considered. The association with hypothyroidism is seen particularly in women with rapid-cycling bipolar illness.[39]

Psychotic symptoms occur with more severe mania but can also occur in conjunction with depression.

Eating disorders, panic attacks, borderline personality disorder, ADHD, and compulsive behavior all may be evidence of bipolar disorder or other psychologic syndromes.[40,41]

Dual diagnosis with substance abuse, especially cocaine and alcohol abuse/dependence, is common. In fact, dependence on these chemicals is more prevalent among people with affective disorder than it is in the general population, although the sequence of their respective occurrences is debated. The ECA study found that 41% of people with bipolar I disorder have abused or were dependent on 1 or more of the following: marijuana, cocaine, opiates, barbiturates, LSD, and PCP; 46% abused or were dependent on alcohol. It is estimated that about 35% (range, 3% to 75%) of people with bipolar disorder also have been diagnosed as being alcoholics, compared with about 8% of the general population.[42] Conversely, the incidence of bipolar disorder in people who abuse alcohol is several times greater than its occurrence in the general population (about 6% to 9%).[43] Alcohol abuse is most likely to occur during manic or mixed phases.

Recent research has found that bipolar patients who abuse drugs or alcohol have an earlier onset and worse course of illness compared with those who do not. These individuals are more likely to experience irritable and dysphoric mood states and increased treatment resistance, and to require hospitalization.[44]

Diagnosis

The chronicity of bipolar disorder makes both diagnosis and management challenging, even for experienced clinicians. Without a detailed history, symptoms may be missed. A focus limited to current symptoms is likely to be misleading, especially when symptom clusters are not clearly apparent.

Diagnostic criteria of mood disorders. The occurrences of major manic and depressive episodes are the key DSM criteria for the diagnosis of bipolar I disorder, including at least 1 manic episode severe enough to impair occupational function or to require hospitalization. A manic episode is defined as a distinct period of elated (or irritable) mood characterized by 3 or more of the following symptoms: grandiosity, needing less sleep, over-talkativeness or pressured speech, racing thoughts, flight of ideas, distractibility, increased goal-directed activity, or impulsive behavior. To meet the criteria for mania, at least 3 of these symptoms must persist for at least a week, 4 if the mood is only irritability.

To meet the criteria for major depression, the depressed mood (or anhedonia) must persist for 2 weeks or longer, with at least 5 symptoms occurring almost daily. Manic and depressive episodes differ significantly in onset and duration. Manic episodes are usually detectable in a matter of hours or at most a few days, whereas depressive episodes can take weeks to fully develop.

Mania or manic episodes. The mood of manic states is typically accompanied by heightened energy and increased physical and mental activity, such as talkativeness; faster speech, thought, and movement; heightened arousal (eg, perceptual acuity, libido, paranoia); sleeplessness; irritability; and impulsivity. Mania is subclassified according to symptoms: hypomania, acute mania, delirious mania, or chronic mania.

In acute mania, the initial mood is like a hypomanic state, but irritability and lability become more prominent. Thinking can race so fast that it becomes fragmented, accompanied by incoherent speech. The person is easily distracted, with activity becoming frenetic, apparently aimless, and occasionally violent. Psychotic symptoms, such as paranoia, grandiose delusions, illusions, and hallucinations, may be part of more severe presentations.

Delirious mania, although relatively rare, is serious. It is characterized by the sudden onset of complete disorientation to time and place. Although it is difficult to differentiate from other types of delirium, delirious mania responds to standard treatments for mania.

A small number of people with bipolar disorder experience chronic mania. Some of this symptomatology may represent inadequate prophylactic treatment, or lack of it.

Mixed mania. Mixed states may appear as transitional phenomena in an otherwise classic bipolar course, or they may make up an independent pattern that dominates the clinical picture. Independent mixed states appear frequently in major bipolar I disease. When they do, they predict a greater likelihood of chronicity and deterioration, including comorbid substance abuse and organicity. Symptoms can be mixed to various degrees. Either mania or depression may appear "pure," with only a single symptom of the opposite mood. For example, a subjective sense that something is wrong can accompany an elevated mood, or a depressed person may have racing thoughts. More complex combinations of symptoms also occur.

The most frequent mix is manic depression, that is, a depressed mood that is concurrent with speeded manic thought processes and physical activity, which are at least as severe as in nonmixed states. Mixed mania is often associated with a history of substance abuse, a high incidence of suicidal ideation, and attempted suicide.

Distinguishing between mixed states, agitated depressions, and borderline conditions is often a clinical challenge. Response to Li tends to be poor; divalproex yields better response rates and is the preferred initial treatment of mixed mania.

Hypomania. The positive feelings experienced during periods of hypomania can be so pleasurable that some patients deliberately do not adhere to the drug regimen that normalizes mood swings. In any case, patients rarely perceive hypomanic episodes as problematic even though family, friends, and significant others recognize the serious consequences to the person and those around him or her.

Mania and hypomania differ chiefly in cognition and the intensity of behavioral changes. The hypomanic person usually feels energetic, self-confident, and has a sense of well-being, but his or her irritability, impaired judgment, and indiscretions can be quite disruptive. An enhanced ability to think and concentrate may improve productivity, promoting an accompanying sense of accomplishment. Hypomania is not associated with psychotic symptoms, nor does it require hospitalization. Sometimes hypomania escalates to acute mania.

Cyclothymia. Characterized by episodes of hypomania and depressive symptoms not meeting criteria for a major depression, cyclothymia is manifested as changes in energy level. The onset is usually in early adulthood, with a subsequent, somewhat sporadic, annual, or biennial pattern. In children and adolescents, the duration must be at least 1 year to receive the diagnosis.[4] Episodes are more common in spring or fall and last for 3 to 10 weeks. Recurrences appear to be unrelated to life events, although a stressful period often precedes the initial episode. Patients with cyclothymia respond to Li and to mood stabilizers about as well as those with full-blown bipolar illness.

Symptom patterns are not different from those of bipolar disorder, except that they are less severe--and so are associated with less functional impairment. Subtypes have been identified and defined according to whether depressive or hypomanic symptoms predominate: In pure cyclothymia, both types of symptoms occur with equal frequency, but the cycle may be irregular. In the predominantly depressed pattern, there are few hypomanic episodes, whereas the hyperthymic pattern is characterized by hypomanic episodes interspersed only occasionally by depressed periods.

Many patients with cyclothymia have a family history of bipolar disorder. About one third eventually develop the full-blown illness, and most patients with bipolar I or II illness had previously experienced mood swings consistent with a pattern of cyclothymia for several years.

Rapid cycling. The occurrence of 4 or more distinct episodes of mania, hypomania, depression, or a mix of each within a 12-month period characterizes rapid cycling. Rapid cycling may comprise 13% to 20% of the incidence of bipolar disorders--with higher percentages reported by tertiary referral centers. Rapid cycling can occur in both bipolar I and II disorders. These patients respond less well to Li and carbamazepine (CBZ) than do patients with classic acute mania. Response to divalproex appears to be better. All current antidepressants, alone or in combination with Li, appear to predispose to rapid cycling.

Because it is easier to define the onset of an episode than its termination, cycle length is measured from the onset of one episode (mania or depression) to the onset of the next episode of the same pole. Episode duration tends to be relatively constant, but cycle lengths vary considerably, which reflects varying periods of normalcy. The average duration of episodes is 4 to 13 months, and depression usually lasts longer than mania. Cycle length depends upon the duration of (1) the index episode, (2) the intervening episode of the opposite pole, and (3) whatever periods of normalcy occur in between.

Diagnostic considerations. Most psychiatrists easily recognize the euphoric manic patient. However, several recent studies have established that nearly 50% of all manic patients have dysphoric or mixed mania at some time during an episode. Subtypes of bipolar disorder, including rapid cycling, mixed episodes, secondary mania, and milder hypomanic states and cyclothymia, are more difficult to distinguish. Obviously, the presence of medical conditions that could contribute to the syndrome or exacerbate or precipitate mania, depression, or cycling must be ruled out. For example, intoxication, thyroid disease, neuropathologies, substance abuse, or over-the-counter medication use should be considered.

Because clinical features may be a key to determining an appropriate therapeutic strategy, there must be emphasis on staging or characterizing the initial illness presentation, including subtype (subsyndromal affective symptoms or euthymia). For example, if patients with rapid cycling of bipolar II symptoms are treated for unipolar depression (as they often are), they may cycle into hypomania/mania or even convert to a rapid cycle. If the person is depressed, it is important to identify anergy (with or without atypical features) or agitation. Recurrent hypomanic periods and severe mood-incongruent psychotic symptoms may presage nonresponse to Li and thus indicate the need for alternative therapy.

Unfortunately, DSM criteria do not include the illness course criteria essential to diagnostic accuracy. Life charting, or mood disorder flow charting, elucidates the temporal pattern, including episodic stability (static or accelerating), symptom sequence (mania-depression-wellness interval/depression-mania-wellness interval/irregular sequencing), and episode frequency (rapid or ultra-rapid cycling). Of course, obtaining an accurate, detailed history is difficult, especially when a person experiences either hypomanic or cyclothymic patterns.

The same patient who did not seek help during hypomanic periods will typically present when he/she experiences depression or suicidal ideation. The depressed patient may have little, if any, awareness of prior hypomania. The diagnostic objective, therefore, is to reconstruct the episodic history of occurrence, duration, and intensity via interviews of both the patient and significant others (eg, family members). It is important to determine whether symptoms have been associated with specific life events. Family members can usually recount if the patient had altered patterns of sleep or energy level, productivity and impulsivity, or mood swings, poor judgment (eg, spending sprees), and hypersexuality.

Factors that may be associated with a favorable course of, or relatively better response to, a specific treatment should be assessed. In general, absence of psychosis or rapid cycling, good premorbid functioning, or a history of a clear-cut affective episode that responded to mood-stabilizing agents are all suggestive of a favorable outcome.

Bipolar disorder may present differently in children and adolescents than in adults. In one study that compared symptomatology of 40 adolescent to 88 adult hospitalized bipolar patients, the adolescents displayed a higher rate of mixed episodes, higher ratings for depressive symptoms, including suicidality and depressed mood, and a lower rate of psychotic features.[45] Such differences in presentation may result in underrecognition and misdiagnosis of bipolar disorder in this age group. Akiskal[46] has suggested that many juvenile-onset depressions may be precursors to adult bipolar disorders, particularly when characterized by irritability, labile moods, and explosive anger indicative of mixed episodes.

Misdiagnosis among older patients is also a possibility. In a small cohort of 13 patients referred to a geriatric mental health center, Baker[47] confirmed the referring diagnosis in 7 of the 13 and gave a new psychiatric diagnosis to 1. Of the remaining 5, 4 who had been diagnosed with schizophrenia were found instead to have an affective disorder (2 bipolar, 2 depressed), and 1 who had been diagnosed with dementia was found to have bipolar disorder. This study suggests that many older psychiatric patients are misdiagnosed when the assessment is not rigorous and systematic.

Life charting. Life charting is a useful method for delineating and monitoring the course of affective illness retrospectively and prospectively, including the effect of interventions. The life chart is a systematic, graphic representation of episode occurrences, preceding and concurrent life events and comorbidities, the severity of functional impairment, and therapeutic interventions. It can be started at an initial interview, even if this is over the phone. The clinician then continues to add details. An episode that requires hospitalization is automatically rated as severe.

Differential diagnosis. Schizophrenia is a common differential consideration, given the significant overlap of symptoms across the 2 conditions. Severe mania in adults or any stage of mania in adolescents may appear indistinguishable from schizophrenia. The DSM criterion for the diagnosis of mania (ie, bipolar disorder, manic episode) with psychotic features is the simultaneous occurrence of mood and psychotic symptoms in the absence of pathognomonic symptoms of schizophrenia. Until a clear differentiation is possible, a provisional diagnosis of bipolar disorder is generally preferred because it carries less stigma and has fewer implications for treatment. The diagnosis can then be changed to schizophrenia if manic symptoms do not respond to treatment, or psychotic symptoms persist for 6 months or longer, or the manic symptoms have a shorter course than the psychoses or occur infrequently. Some studies have indicated that upper-class and middle-class people are more likely to be diagnosed as manic-depressive than people with lower socioeconomic status, especially urban blacks, who are often mistakenly diagnosed as schizophrenic.[48]

Borderline personality disorder is distinguishable from rapid cycling by the degree of variation exhibited over hours or days and the typically quick response to appropriate intervention or stimulation. Also, sleep and appetite patterns are usually not altered. Borderline personality disorder is a pervasive pattern of instability encompassing relationships (extreme idealization and devaluation), self-image (distorted), affect (markedly reactive, intense, inappropriate, and uncontrolled), and control over impulses (reckless or binge spending, eating, sex, substance use, etc.), which begins by early adulthood. The person with borderline personality may experience chronic feelings of emptiness and transient stress-related paranoia and may exhibit recurrent suicidal or self-mutilating behavior, gestures, or threats. Many of the symptoms of bipolar disorder overlap with those of mania, and approximately 30% of patients with borderline personality meet criteria for a bipolar disorder.

Because drugs and bipolar illness both alter mood, cognition, and behavior, there is considerable symptom overlap between drug abusers and persons with manic-depressive illness. Thus, it is not surprising that substance abuse can mask bipolar symptoms. Substance abuse can also precipitate an episode of manic or depressive psychosis. Moreover, psychoses induced by LSD, PCP, or amphetamines can be attributed to schizophrenia rather than bipolar disorder. Of course, drug effects can mimic nearly any psychiatric disorder, particularly with chronic drug use. Differential diagnosis can be aided by paying attention to symptom chronology and family history, by conducting a detailed interview about drug use, and, as sometimes indicated, by obtaining a drug-screen urinalysis.

Summary

Bipolar disorder is a chronic, lifelong condition that requires careful observation and history-taking to make an accurate diagnosis. To ensure diagnostic accuracy, it is important to carefully consider the illness course and treatment response, family history, and the presence or absence of affective symptoms and their relationship to psychosis. Bipolar can be confused with depression, since some patients do not view their hypomanic or manic episodes as a disorder and only come for clinical consultation during depressed episodes.

About the Author

Dr. Bowden is Nancy U. Karren Professor of Psychiatry and Pharmacology at the University of Texas Health Science Center at San Antonio and is Editor-in-Chief of Medscape Mental Health.