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Whereas full-blown mania is unmistakable, milder ‘hypomanic’ episodes are often missed since patients regularly only present during depressive episodes and can be misdiagnosed as having unipolar depressive illness.
The diagnosis of bipolar II disorder exists in the American Psychiatric Association’s DSM classification manuals (current edition DSM-5 was published in 2013) and not in the World Health Organisation’s current classification manual of ICD-10. However, it is likely to be included in ICD-11, due in 2018, and is used regularly by psychiatrists in their clinical practice worldwide, who find it useful to differentiate bipolar I and bipolar II disorder. The diagnosis of bipolar I disorder is given to patients as a lifetime diagnosis if they have experienced at least one manic episode. Most patients experience more than one such episode as well as episodes of depressed mood. In fact a minority (15 per cent) of patients with bipolar I disorder just experience repeated manic episodes without depressive swings, however, the concept of ‘unipolar mania’ is not currently included in diagnostic classification manuals, since patients are considered at high-risk of future depressive episodes even if they have mostly experienced elated mood.
Ms A is a 32-year-old secretary living in shared rental accommodation. She smokes 10 cigarettes per day and drinks socially at the weekends. She does not take any illicit substances. Her relationship with her boyfriend of 12 months is going well and they are planning to live together in his apartment.
She experienced her first episode of depression when she was aged 19, shortly after she lived away from home for the first time. She was treated with escitalopram by her GP. The episode resolved after about three months. She subsequently experienced a number of further bouts of depressive symptoms during her 20s. Sometimes these resolved on their own. At other times she attended her GP and each time was prescribed an SSRI antidepressant, which she tended to stop herself after several weeks. However these episodes increased in frequency and severity and by her late 20s, she was having two episodes of troublesome depressive illness each year.
At the age of 30, while taking the antidepressant escitalopram, she became more overactive and displayed disinhibited behaviour. Her thoughts began going faster than normal and she reported waking early in the morning, full of energy. Her friends and family noticed that she was more talkative than usual and she behaved in ways that were inappropriate – most notably she telephoned her boss at 2am one night in order to notify him about a work matter that she was worrying about. She was more irritable at work and had begun snapping at work colleagues over minor matters. She had started going out to pubs on her own and was more likely to start chatting to strangers. There were no delusions or hallucinations. She realised that she “wasn’t right”, felt “anxious and stressed” and was concerned that she could not seem to get to sleep. She accepted an urgent referral to psychiatric services and was assessed in the community mental health team base. Her escitalopram antidepressant was stopped and she was commenced on olanzapine and given an outpatient appointment and community mental health nurse follow-up. In the subsequent days her sleep improved and her mood returned to normal.
On further probing of her history in psychiatric consultations, she admitted to several previous milder episodes of being overactive and irritable throughout her 20s. During these episodes she tended to feel better than normal, needing less sleep, being more active physically, and trying new hobbies for brief periods. These episodes sometimes lasted for a few days and the longest lasted for a few weeks. She didn’t consider them “abnormal” because she felt in control of her behaviour and she put them down to just part of her “personality”. She also reported that her maternal uncle was admitted to hospital with “manic-depression” in his 30s for several weeks and had taken the drug lithium for many years after that. Routine bloods confirmed that her haematological, renal, hepatic and thyroid function were all within normal ranges. She was diagnosed with bipolar II disorder.
After about six weeks of olanzapine treatment she developed depressive symptoms, with tearfulness, social withdrawal, anxiety, feelings of worthlessness, difficulty staying asleep at night and struggling to get out of bed in the morning. She felt tired most of the day. She had been consuming a lot of high calorie food and had put on 5kg in weight. Her olanzapine was stopped by the treating team. She was commenced on lamotrigine and her mood improved, although she continued to experience anxiety symptoms. Quetiapine was added to her medication regime and increased to a dose of 300mg. She has continued on lamotrigine 150mg BD and quetiapine 300mg nocte for two years now. She continues to experience some mood swings especially in response to social stressors, but she states that these are much milder and less troublesome than they had been previously. She sleeps well and has made other efforts to regularise her lifestyle, as recommended by her psychiatrist. These include a consistent sleep routine, regular exercise, avoiding excess alcohol consumption and engaging in simple relaxation and stress control techniques. She is now thinking about starting a family with her boyfriend, but is concerned about passing on her illness to her children and whether it is safe to take her medication during pregnancy.
The diagnosis of bipolar II disorder is given to patients as a lifetime diagnosis when a patient experiences at least one hypomanic episode and at least one depressive episode. Depressive episodes tend to be more numerous in bipolar II disorder and patients often do not present in their hypomanic episodes. About 10 per cent of individuals initially diagnosed as having bipolar II disorder on the basis of hypomanic episodes will eventually experience a full blown manic episode, at which point their lifetime diagnosis would be regraded to bipolar I disorder. There are specific clinical criteria that should be met for the diagnosis of an individual episode of mood disorder – included here are the criteria in accordance with DSM-5:
1) Manic episode
Core criteria for a manic episode are a distinct period of elated or irritable mood accompanied by persistent overactivity and increased energy lasting for at least a week and accompanied by at least three of the following associated symptoms (four if only irritability rather than elated mood is present):
Reduced need for sleep;
Increased activity or psychomotor agitation;
Racing thoughts or ‘flight of ideas’;
Disinhibited behaviour (eg, socially inappropriate, overspending);
In more severe episodes, grandiosity crosses the threshold of psychosis, the most common features of which are mood congruent grandiose delusions and auditory hallucinations.
2) Hypomanic episode
Core and associated criteria for a hypomanic episode are the same as for a manic episode, however (i) the time criterion is four days and (ii) the episode is not severe enough to cause marked social and occupational dysfunction. The episode must nevertheless be clearly different from the person’s baseline and mood disturbance/functional change is observable by others. Unlike a manic episode, a hypomanic episode is often associated with enhanced goal-directed and therefore effective and even creative behaviours, is unlikely to require hospitalisation and would not be severe enough to drive symptoms of psychosis.
3) Depressive episode
Diagnostic criteria for a depressive episode in the context of a lifetime diagnosis of bipolar disorder are essentially the same as those for unipolar depression. These comprise core symptoms of persistently depressed mood and/or loss of interest or ability to enjoy things (anhedonia) for at least two weeks accompanied by at least four of the following associated features:
Substantial weight loss or decrease in appetite;
Insomnia, characteristically waking early in the morning (or hypersomnia in atypical cases);
Psychomotor retardation (or agitation);
Worthlessness or guilt;
Reduced ability to concentrate;
Recurrent thoughts of death or suicide.
Episodes of bipolar depression are often more severe and long lasting than those of unipolar depression and have poorer response rates to antidepressant medication than unipolar depression.
Bipolar disorder is unique amongst mental illnesses in being triphasic in nature and the treatment of the phases of mania/hypomania, bipolar depression and maintenance differs. Anti-manic agents are used for the acute treatment of mania/hypomania. For the most part these are antipsychotic agents that are also used in the treatment of schizophrenia and other psychoses, such as olanzapine, risperidone, quetiapine, aripiprazole and haloperidol. Given the agitation and sleep disturbance characteristic of a manic episode, often short-term benzodiazepines are used for their sedative properties, especially during inpatient care. However, ‘mood stabilising’ medications, such as lithium carbonate and sodium valproate are also effective anti-manic agents and these may be used on their own to resolve an elated episode — in practice this tends to apply largely to mild hypomanic episodes in the context of bipolar II disorder, since the level of agitation and distress associated with a full blown manic episode tends to warrant the more calming and sedative effects of antipsychotic medication.
Bipolar depression on the other hand requires a different approach, the initial aspect of which is to optimise mood stabilising treatment – for example, adding a mood stabiliser or optimising its dose (serum level in the case of lithium carbonate). Some patients will respond to a mood stabiliser such as lamotrigine when used as monotherapy, as in the case study above. Others may require the addition of more than one mood stabiliser or the addition of a mood elevating antipsychotic medication (eg, quetiapine) or an antidepressant medication — however antidepressants should not be prescribed on their own for the treatment of bipolar depression due to the risk of precipitating a manic/hypomanic episode and instead only in combination with mood stabilising treatment in order to reduce this risk.
A general treatment principle for the maintenance or prophylaxis phase of bipolar disorder, whether I or II, is the inclusion of mood stabilising medication to reduce the risk of future episodes of mood exacerbation. Although treatment success for an individual with a manic/hypomanic episode is very high at over 95 per cent, the vast majority of patients will experience further episodes without prophylaxis. As well as mood stabilisers such as lithium carbonate, sodium valproate, carbamazepine and lamotrigine, antipsychotic medications such as quetiapine, aripiprazole, risperidone and olanzapine have a role to play in the maintenance phase of bipolar disorder. Such antipsychotic medications are often included within a medication regime for patients with bipolar disorder, both because of their mood stabilising properties and also because they have calming and sedative properties that can be helpful for anxiolysis and sleep control, as in the case of Ms A in this article’s case report.
Effective psychosocial interventions for bipolar disorder largely are focused upon psychoeducation and there is clear trial evidence of the benefit of such programmes. Psychoeducation can be delivered in individual or group formats and focuses upon education about the illness and its medical treatment, medication adherence and monitoring, optimising lifestyle regulation and sleep management, recognising relapse signatures and intervening early, minimising destabilisers, such as illicit substance and alcohol misuse.
References available on request