Bipolar disorder is characterised by cycles of mania and depression, which vary in intensity, duration and frequency. In its classic presentation, particularly when manic symptoms are evident, bipolar disorder does not usually present a diagnostic dilemma to the physician. However, milder cases of mania or depressive episodes interspersed with hypomania may make diagnosis more difficult. Early onset bipolar disorder – especially pre-puberty – may also be a diagnostic challenge.
When confronted with psychotic symptoms, some clinicians automatically diagnose schizophrenia. Bipolar disorder can however, also present with psychotic symptoms in both manic and the depressive phases, leading to bipolar disorder potentially being misdiagnosed as schizophrenia. The depressive phase of bipolar disorder usually precedes a manic or hypomanic episode, making it difficult to predict if bipolarity will be the result of an initial depressive episode as the disorder progresses over time. The following symptoms are more often associated with bipolar disorder than with other psychotic conditions:
In moderate to severe cases, patients with bipolar disorder are usually quickly identified. However, in mild cases the identification and treatment can be delayed – usually as a result of misdiagnosis or absence of diagnosis. In adolescents, the acceptance of chaotic behaviour and mood dysregulation as a part of normal development can prevent the recognition of a significant mood disorder. Therefore, particular attention should be paid to the early detection and appropriate management of mood disorders in the primary care setting.
One study noted that some patients with bipolar disorder experienced delays of up to 5 years before a proper diagnosis was made (Evans, 2000). This was partly due to patients not seeking treatment; 35% of patients failed to seek treatment for as long as 10 years from their initial episode. Delays in diagnosis are also due to the difficulty of diagnosing bipolar disorder; 34% of patients received a diagnosis other than bipolar disorder when they first consulted a physician (Evans, 2000).
The diagnostic criteria for depressive and manic episodes are listed below.
DSM IV diagnostic criteria for a major depressive episode (American Psychiatric Association, 1994)
DSM IV Diagnostic criteria for a manic episode (American Psychiatric Association, 1994)
Manic episodes can be subdivided into three groups: mania, hypomania and mixed episode mania. Mania is the classic acute manic state, as described in the DSM-IV criteria above. Hypomania shares the same clinical features as pure mania, but is less severe, may not require hospitalisation and may cause less impairment in functioning. The symptoms are still noticeable to others and are often associated with significant social and vocational difficulties (Evans, 2000; NIMH, 2000).
In the majority of cases, patients will experience distinct episodes of mania and depression. However, depressive symptoms can often occur during a manic episode. This is called a mixed episode and is defined by sufficient depressive and manic symptoms occurring concurrently, such that diagnostic criteria for both conditions are met. Approximately 30% of patients with bipolar disorder will experience a mixed symptom episode during the course of their illness (Keck, Jr. et al, 2001).
Secondary mania is mania (or hypomania/mixed mania) occurring as a result of a concurrent medical condition. It can be differentiated from primary mania by a later age of onset in patients with no family history of mania or affective disorders. Treatment for secondary mania may differ from that of primary mania. Secondary mania associated with the central nervous system (CNS) or renal disease may be more effectively treated with anticonvulsants whereas secondary mania associated with liver disease may be more effectively treated with lithium (Evans, 2000).Read about the treatment of bipolar disorder.
Bipolar I and II Disorder
There are 2 distinct forms of bipolar disorder and different criteria must be met for a diagnosis of either, see below.
Required for the diagnosis of bipolar I(Keck, Jr. et al, 2001; NIMH, 2000):
Required for the diagnosis of bipolar II:
Diagnostic Instruments and Rating Scales
Diagnostic instruments are available to assist the clinician in the diagnosis of bipolar disorder. There are a number of useful tools, including the Structured Clinical Interview for DSM-IV (SCID), Schedule for Affective Disorders and Schizophrenia (SADS) and the Mini-Mental State Exam (MINI). These all require extensive clinician training for optimal use and are not suitable for screening.
A new screening questionnaire for bipolar disorder – the Mood Disorders Questionnaire (MDQ) – has recently become available. While it has only been tested on 198 patients as a screening instrument for bipolar spectrum in psychiatry; it was shown to be both specific and sensitive in distinguishing bipolar disorder from other psychiatric conditions (Hirschfeld et al, 2000; Maj et al, 2002). Each new patient should be asked to complete a MDQ before seeing a clinician and if the answer to two or more questions were positive, the patient should be assessed in greater detail to exclude a diagnosis of bipolar disorder.
The severity of the depressive and manic episodes can be measured objectively, using a variety of symptom rating scales. Some of the tools most often used in the assessment of patients with bipolar disorder are the Young Mania Scale and the Brief Psychiatric Rating Scale; both of these require rater training to ensure rating reliability.
Last updated: 20.12.2011