Abstract
Recent work suggests that a broad clinical spectrum of bipolar disorder is more common than previously thought and that the disorder may affect up to 5% of the population. The correct definition and diagnosis of hypomania is central to the identification of bipolar disorder. In this review we focus on recent diagnostic and clinical advances relating to bipolar disorder, with particular reference to hypomanic states. We also highlight some of the controversies in this field and discuss ways in which clinicians might improve their detection of bipolar disorders.
‘When you’re high it’s tremendous. The ideas and feelings are fast and frequent … Shyness goes, the right words and gestures are suddenly there, the power to captivate others a felt certainty … Sensuality is pervasive and the desire to seduce and be seduced irresistible’ (Jamison, 1995: p. 67).
‘In hypomania, there is an increased pressure of speech with prolixity, an abnormal liveliness of expressive movements, superficial bustling activity and a tendency to be argumentative and irritable if thwarted in any way. The patient is interested in everything, starts many projects, and finishes none … the elated mood leads to faulty judgement and a lack of consideration for others … hypersexuality may lead to venereal disease in men and pregnancy in women … the mental illness may be obvious only to the relatives and doctors, and other outside observers may merely regard the patient as a cheerful chap or somewhat of a “card” ’ (Fish, quoted by Hamilton, 1974: p. 73).
Although Kay Jamison’s evocative description of the early stages of mania contrasts with the phenomenological account provided by Frank Fish (writing in the 1960s), these two quotations illustrate a fundamental point about the presentation and diagnosis of hypomanic states. People with mild manic symptoms rarely complain about feeling unwell (indeed, many enjoy their ‘supernormal’ levels of functioning), whereas family members and psychiatrists will usually be quick to recognise the behavioural manifestations of the illness. In this review, we focus on some of the recent advances in our understanding of the presentation and detection of hypomania.
Diagnostic issues
The study of less severe forms of bipolar disorder has been neglected for many years, but developments in clinical phenomenology, nosology and epidemiology have given rise to renewed interest in the correct definition and diagnosis of hypomania.
Categories v. dimensions
Many of the diagnoses used in psychiatry, including those described in ICD–10 (World Health Organization, 1992) and DSM–IV (American Psychiatric Association, 1994), are categorical in nature and based on a checklist approach that specifies an arbitrary number of symptoms as a threshold for diagnosis. Although these classifications have been of considerable value, they fail to reflect the clinical reality that psychiatric presentations are often dimensional rather than all-or-nothing phenomena.
For mood disorders, one of the consequences of this has been the proliferation of a large collection of diagnoses, ranging from major (unipolar) depression through to severe psychotic disorders such as schizoaffective disorder. Not surprisingly, the dividing line between what might be considered normal temperament and full-blown mood disorder can often appear blurred. A good illustration of this is the retention of sub-threshold disorders such as dysthymia and cyclothymia in ICD–10 and DSM–IV. For bipolar disorder, the accurate detection of hypomania is of pivotal diagnostic importance and has considerable implications for treatment.
What is the correct definition of hypomania?
Although ICD–10 and DSM–IV are generally in agreement over what constitutes a core manic symptom, there are important differences in the guidance that they provide for the diagnosis of hypomania. In ICD–10, hypomania is considered to be a lesser degree of mania lasting ‘several days’ and causing ‘considerable interference with work or social activity’. In contrast, DSM–IV stipulates that hypomania occurs ‘without [my italics] marked social or occupational dysfunction’ (leading to a diagnosis of bipolar II disorder). Full-blown mania in DSM–IV refers to any persistent elevation of mood lasting more than 1 week that causes functional impairment (and leads to a diagnosis of bipolar I disorder).
Thus, many patients with ICD–10-defined hypomania may actually satisfy DSM–IV criteria for mania. This confusion is compounded in the UK by an apparent overuse of the term ‘hypomania’. It is not uncommon for a patient who has been hospitalised for weeks with severe mania to be given a discharge diagnosis of hypomania (Goodwin, 2002).
Some of the core manic symptoms of hypomania may be more common than others. For example, ‘increased activity’ and ‘increased energy’ are almost universal, whereas ‘increased talkativeness’ does not feature in over a quarter of hypomanic presentations (Fig. 1⇓) (Wicki & Ansgt, 1991).
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Frequency of core manic symptoms in hypomania (data from Wicki & Angst, 1991).
Prevalence rates for bipolar disorders depend on the diagnostic criteria applied to people with recurrent major depression, and central to this issue is the correct definition of the boundaries of hypomania. The minimum duration required for a diagnosis of hypomania in the DSM has changed significantly over the years. In the Research Diagnostic Criteria it was 2 days (Spitzer et al, 1978), in DSM–III (1980) and DSM–III–R (1987) it was not specified, and in DSM–IV it has been set arbitrarily at 4 days. Within the past few years, a group of experts on bipolar disorder have recommended reverting to the threshold of 2 days, for two reasons. First, most people with bipolar disorder report a median duration of hypomanic symptoms of 1–3 days (rather than 4 or more) (Benazzi & Akiskal, 2003). Second, several longitudinal studies have reported that people who experience brief hypomanic periods do not differ from those with longer periods in terms of features age at illness onset, family history of mania and lifetime illness chronicity (Akiskal et al, 2000; Angst et al, 2003; Benazzi & Akiskal, 2003; Judd et al, 2003).
Dysphoric (or mixed) hypomania
The traditional view of hypomania as a predominantly euphoric mental state is challenged by recent studies. Many people with bipolar disorder experience ‘dysphoric’ or ‘mixed’ hypomanic periods that can be diagnostically challenging (Akiskal et al, 2003a). Some studies have estimated that at least half of all mood episodes in bipolar disorder are mixed presentations (Cassidy & Carroll, 2001).
In a recent 7-year naturalistic study of 908 people with bipolar disorder within the Stanley Bipolar Treatment Network, Suppes et al(2005) found that out of 1044 visits in which the patients met DSM–IV criteria for hypomania, in 57% of cases they also met criteria for ‘mixed hypomania’ (defined as a Young Mania Rating Scale score ≥12 and an Inventory of Depressive Symptomatology score ≥15). Mixed hypomania was much more likely in women than in men, supporting previous findigns of an overrepresentation of mixed states in female patients with bipolar disorder (Arnold et al, 2000; Benazzi, 2003).
Differential diagnosis of hypomania
The diagnosis of hypomania can also be more difficult because hypomanic symptoms can feature prominently in a number of other conditions. A commonly encountered difficulty is the differentiation of hypomania from periods of elevated mood, overactivity and grandiosity that can occur in individuals with extrovert or cyclothymic personalities. Similarly, people with DSM–IV cluster B personality disorders (particularly borderline personality disorder) who do not have a mood disorder can present with high levels of affective arousal that can mimic hypomania. Diagnosis in these patients is often made even more difficult by their concurrent use of drugs such as cannabis, amphetamine and cocaine.
Leaving aside concerns about the clinical validity of a diagnosis of adult attention-deficit hyperactivity disorder (ADHD) (Asherson, 2004; Zwi & York, 2004), some individuals presenting with hyperactivity, disinhibition and inattention may be misdiagnosed as being hypomanic. However, the differentiation of ADHD from hypomania should usually be straightforward if based on a systematic assessment for other hypomanic features such as elevated or irritable mood, inflated self-esteem and decreased need for sleep.
As with all psychiatric diagnoses, care should be taken to eliminate a clear organic cause for hypomanic symptoms, such as the use of stimulant drugs or an endocrine abnormality like hyperthyroidism. Box 1⇓ shows the most common differential diagnoses for hypomania. A key issue in its differential diagnosis is that the psychiatric assessment should focus not only on the present mental state but also on the longitudinal history and temporal pattern of recurrent mood episodes (be they depressive, manic or mixed).
Differential diagnosis of hypomania
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Levels of elevated mood and overactivity that lie within normal limits
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Drug misuse: cannabis, amphetamine, methylenedioxymethamphetamine (MDMA, ecstasy) and cocaine
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Cyclothymia
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Cluster B personality disorder (e.g. borderline personality disorder)
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Attention-deficit hyperactivity disorder
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Endocrinopathy such as hyperthyroidism (rare)