Bipolar disorder: diagnostic issues

John W G Tiller and Isaac Schweitzer
Med J Aust 2010; 193 (4): S5. || doi: 10.5694/j.1326-5377.2010.tb03889.x
Published online: 16 August 2010

The term bipolar disorder applies to a range of conditions that are likely to have different aetiologies, including genetic or family vulnerability, precipitation by stressful life events, physical illness or drugs including antidepressants. The essential features of bipolar disorders are cyclical mood disorders including distinct sustained periods of mood elevation. Mood elevation is critical in differentiation from unipolar disorders, specifically major depressive disorder, recurrent type.

Bipolar disorders are classified in a number of ways. One diagnostic system is described in the Diagnostic and statistical manual of mental disorders, fourth edition, text revision (DSM-IV-TR),1 which is United States based; another is described in the International statistical classification of diseases and related health problems, 10th revision (ICD-10),2 which is World Health Organization and predominantly European based. Although these diagnostic classifications have similarities, there are several differences in their detail. Here we refer to the DSM-IV-TR1 criteria, unless otherwise specified. Box 1 provides a summarised approach to classifying bipolar disorder.

Bipolar I disorder

The most florid presentation of bipolar disorder is type I, in which mood elevations are marked and include clinical features of mania (see Box 2 for a guide derived from DSM-IV-TR criteria for a manic episode1). This illness has a distinct period of abnormality with persistently elevated, expansive, or irritable mood lasting at least a week, or requiring hospitalisation.

Individuals who are manic will experience disturbances in their perception, thinking and behaviour, which are largely determined by their illness rather than by external circumstances. For instance, while a patient is psychotic, he or she may report hallucinations such as voices saying he or she is wonderful and the leader of the people, or even a representative of God. These hallucinations are usually, but not always, consistent and congruent with patients’ mood states. They may have grandiose thinking patterns, incongruent with their actual circumstances in life. They may, for example, believe they are extremely powerful, king of the world, or even “the Messiah”.

Thinking can be so fast that the patient’s speech cannot keep up. Patients may be distractible, expansive and irritable. Although at first they might seem able to multitask, they usually end up moving from one activity to another in a distracted fashion. As the illness worsens, they tend to become more disorganised.

Typically, the need for sleep is reduced; patients may feel rested after only 2 or 3 hours of sleep, and may be so preoccupied and active that they do not consume enough food and fluids. If this persists, they may collapse from exhaustion. They tend to be socially disinhibited, loud and intrusive, and have impaired judgement. Risk taking can increase — for example, driving too fast, drinking excessive amounts of alcohol or using illicit drugs. Patients may gamble exuberantly or spend excessively, beyond their normal budget and financial resources. Sexual arousal and libido may increase during mania and patients can get into sexual misadventures with partners who they may never have chosen when not ill. This may lead to unprotected sex and expose patients to sexually transmitted diseases. These complications can add to the burden of disease and disability, including financial complications such as bankruptcy.

Although patients with bipolar disorder can seriously endanger their lives by these high-risk activities, including activities undertaken while under the influence of drugs or alcohol, they rarely attempt or commit suicide during this phase of the illness. Nonetheless, they are at increased risk of accidents and may die by misadventure.


Although bipolar disorder is defined by mood elevation, the greatest disability and risk occurs during depression, which is typically the dominant phase of the illness, especially for those who are untreated. Depression typically takes up 30%–50% of the patient’s life and mania takes up about 5%–10%, with a semblance of normality making up the remainder of the patient’s life.3-5

It is common for individuals to have one or more episodes of bipolar depression before their first manic episode. An initial diagnosis of major depressive disorder is often made until a manic episode results in a change of diagnosis to bipolar I disorder.

Features of depression associated with bipolar disorder (referred to as bipolar depression) are essentially the same as those of major depression (see Box 3 for a guide derived from DSM-IV-TR criteria for a major depressive episode1) but occur in patients with a history of mania or hypomania. Depressive features themselves cannot distinguish bipolar disorder from unipolar depression, although some features appear more commonly in bipolar disorder.6 These include the tendency to have atypical features of depression, with symptoms such as hypersomnia (rather than insomnia) and hyperphagia (rather than anorexia). These features are indicative, rather than diagnostic, of bipolar depression. The presence of psychotic symptoms in the depressive phase also suggests an increased likelihood of bipolar disorder (see Mitchell et al).7

During bipolar depression, patients can feel desperate about the depth and severity of and disability from their low mood. They may not recall or be able to think of the prospect of returning to normal mood and normal life — they may not even recall antecedent mood elevations. They can also feel suicidal; 10%–19% of patients diagnosed with bipolar disorder commit suicide.8 Suicide usually occurs during a depressive episode (79%)9 when the risk of suicide is 15 times that of the general population.10 Patients with bipolar disorder who have attempted suicide are over four times more likely than those who have not attempted suicide to subsequently attempt or complete suicide.11

As bipolar depression requires different treatments than those used for unipolar depression, treatment resistance (ie, the loss of effectiveness of antidepressants that initially appeared effective) may be a hint of bipolar disorder. Although this may seem paradoxical, antidepressants may be ineffective, only briefly effective or more destabilising than helpful for many patients with bipolar disorder. Antidepressant use is more likely to increase the rate of mood cycling, induce mood elevation or result in a mixed state than mood-stabilising agents (see Malhi et al).12

Bipolar II disorder

Bipolar II disorder is characterised by cyclical mood and defined by mood elevation in a patient who has had at least one or more major depressive episodes. The persistently elevated, expansive or irritable mood (referred to as hypomania) only needs to last at least 4 days (see Box 4 for a guide derived from DSM-IV-TR criteria for a hypomanic episode1), rather than a week as in mania; however, if the patient is hospitalised during hypomania, the diagnosis becomes bipolar I disorder. The ICD-102 criteria differentiate hypomania on the basis of a persistent mild elevation of mood with less disorganisation than in mania, rather than the more marked mood elevation and disorganisation of mania.

Patients may experience elevation in quite a subtle way that they perceive as constructive and refer to as “my usual self”. In this phase, they may need less sleep than normal yet do not feel tired. They may feel more creative than usual, active, alive, energetic and productive, and can indeed be so. Sociability and sex drive increase, and risk taking may occur. Patients can present as the “life and soul of a party”. Patients are unlikely to present to doctors with hypomania. They may value hypomania as their preferred state, and they can feel that a normal mood is “below par” or describe normal mood as “depressed”. Although some patients may make disadvantageous business and personal decisions because their judgement is affected by their illness, others can be extraordinarily successful through taking business or personal risks. The diagnosis of hypomania is typically made in retrospect and it is helpful to interview a significant other when making the diagnosis; comments such as “he is up and down like a yoyo” may reflect hypomania.

Mixed episodes

Mixed episodes occur when patients have features of mood elevation and depression simultaneously. DSM-IV-TR1 criteria for a mixed episode require that the patient has full features of both mania and depression. Using this approach, mixed episodes do not include mixed states where only some criteria are met, or states in which there are simultaneous features of both elevation and depression but not the severity of either mania or major depression. Many experts in psychiatry view the DSM-IV-TR1 criteria as being too strict and limiting. In contrast, ICD-102 criteria allow for the diagnosis of a mixed episode in the presence of either of a mixture of manic and depressive symptoms or a rapid alteration between manic and depressive symptoms.

Clinicians must be mindful that mania and depression can coexist, and that patients with bipolar disorder may present as angry, irritable and dysphoric. In these circumstances, antidepressants may worsen symptoms.

Substance misuse

Bipolar illnesses are often complicated by use of alcohol or illicit drugs. Substance misuse is more common in bipolar I disorder (50%) than bipolar II disorder (39%); alcohol is the most commonly misused substance (42% and 34% for bipolar I and II, respectively),3 and illicit drug use is also common. Sometimes the mood disorder will be undiagnosed in the context of florid substance misuse. Diagnosis can be problematic in such patients because alcohol and many drugs can cause substantive mood alterations that remit without treatment once substance use ceases.

Neurological changes in bipolar disorder

Consistent with a prevailing view that bipolar disorder has a primary biological basis, structural neuroimaging studies have revealed a reduction in central nervous system volume in patients with bipolar I disorder and increased rates of deep white matter hyperintensities.13 There may be a loss of hippocampal volume, consistent with that seen in untreated depression.14,15 There are also significant cognitive deficits in bipolar disorder, even during euthymia, which can impede functioning.16 These impairments can result in patients who seem to have achieved symptomatic recovery not regaining full social and occupational rehabilitation. Thus, a goal of treatment should be a full remission of all symptoms and rehabilitation, rather than only alleviation of mood symptoms.16


Diagnosis of bipolar disorder requires at least one episode of mood elevation, either mania or hypomania. However, the dominant and most disabling phase of this illness is depression. Establishing the correct diagnosis is important as the prognosis is different to that for major depressive disorder, and treatments are generally different. Diagnosis may not be possible on first presentation of depression, but only made after a subsequent mood elevation. Clinicians should review diagnoses regularly, and remain open to bipolar diagnoses as it is possible to confuse these with major depressive disorder, schizophrenia and substance misuse. Corollaries of effective diagnosis are an informed patient and appropriate treatments, with the potential for better outcomes.

  • John W G Tiller1
  • Isaac Schweitzer2

  • 1 Department of Psychiatry, Albert Road Clinic, University of Melbourne, Melbourne, VIC.
  • 2 Department of Psychiatry, The Melbourne Clinic, University of Melbourne, Melbourne, VIC.



We thank Ms Iveta Krivonos, Research Assistant, for assisting in the preparation of this article.

Competing interests:

John Tiller is on the Board of Directors of Therapeutic Guidelines Limited (unpaid position) and has received speaker fees and travel assistance from AstraZeneca, Eli Lilly, Lundbeck, Pfizer, Schering-Plough and Wyeth. Isaac Schweitzer has received payment for board membership and honoraria from AstraZeneca, Eli Lilly, Lundbeck, Pfizer, Schering-Plough and Wyeth.

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