Epidemiology

Recent estimates place mental health disorders as one of the three leading causes of total burden of disease and injury in Australia, alongside cancer and cardiovascular disease.^4,5,6 In middle age, it is the leading cause of non-fatal disease burden in the Australian population. There is no doubt that mental health disorders have a high prevalence, are disabling and are high cost in both human and socioeconomic terms.^4,5

In terms of disability, it has been estimated that having moderate to severe depression is the equivalent of having congestive cardiac failure,⁶ chronic severe asthma or chronic hepatitis B.⁵ Severe post traumatic stress syndrome was comparable to the disability from paraplegia and severe schizophrenia was comparable to quadriplegia, in terms of disability.⁵ Over the last 10 years emergency department (ED) presentations have risen 8% in the USA, whereas mental health presentations for the same time period have risen 38%, contributing significantly to ED overcrowding.⁷ This trend has been mirrored in Australia.

Contributing to this may be:

The Australian Institute of Health and Welfare report into Mental Health Services in 2007 estimated that there were over 190 000 occasions of service to Australian EDs where the primary problem was thought to be due to a mental health disorder. This was estimated to be approximately 3.2% of total presentations to public hospital EDs.⁴ This correlates well with other studies and US figures, which estimate 2–6 % of emergency medicine presentations are primarily due to mental health disorders.^1,7,8,9

Two-thirds of these people are between the ages of 15 and 44 years (compared to 42% for the general population presenting to a suburban ED. 29% have anxiety and neurotic disorders, 21% mental and behavioural disorders due to psychoactive substance abuse, 19% mood disorders and 17% schizophrenia or delusional disorders.⁷

This, of course, is a gross underestimate of the prevalence of mental health disease in the ED as many patients remain undiagnosed, and many have active medical conditions and a mental health diagnosis may be secondary.⁸

It is estimated that 17.7% of adult Australians admitted to hospital report a mental health issue in the previous 12 months. An estimated 0.4–0.7% of the adult population suffer from a psychotic episode in any one year.⁵ Mental health issues are highly prevalent and relevant.

Introduction to the mental state examination

The mainstreaming of mental health patients into general EDs has brought problems and anxieties for staff. Staff often feel a lack of confidence because they are dealing with a population of patients unfamiliar to them. They also feel inadequate due to poor assessment skills.^9,10

Mental health patients are often seen as ‘low yield’, unrewarding and there is often a negative attitude expressed toward them.^9,10 A high proportion have drug and alcohol intoxication. This confounds the evaluation and treatment, lengthens the stay of these patients within the ED and delays their disposition. Mental health patients are sometimes perceived as ‘frequent flyers’ – victims of chronic disease that can never be cured – and can be seen as burdensome and unrewarding.

These negative attitudes have resulted in mental health patients being assigned lower triage categories and longer waits to be seen by staff than mainstream patients. They have a higher chance of leaving before assessment has begun or is complete and the overall increase in length of assessment time has the potential to increase violence in the ED.^9,10

With this in mind, there has been much work over the last 10 years on the assessment of mental health patients in a general ED.

ABC of the MSE

A mental state examination (MSE) is analogous to the management of severe trauma. There is an initial risk assessment looking for immediately life-threatening risks to the patient or staff. The triage nurse and the treating doctor should then obtain a brief collateral history from the emergency services or carers, and initial management is based on this assessment. Regardless of threat, all assessments should balance the safety of both patient and staff with privacy and dignity.⁹

Assessment should be based on:²

• appearance and affect

• behaviour

• conversation

• drug and/or alcohol intoxication.

If the situation is relatively controlled, the formal mental health assessment should then take place. Further information is gathered from the community. A provisional assessment and management plan is developed in conjunction with the mental health team, and appropriate disposition is arranged (Fig. 20.1.1).

Fig. 20.1.1 The mental health assessment process.

Triage

The Mental Health Triage Scale (Table 20.1.2) has been developed and modified to be included into the Australian Triage Scale (ATS).^3,9,11 It is very broad and asks the triage nurse to make four assessments: risk of suicide/self harm, risk of aggression/harm to others, risk of absconding and whether the patient is intoxicated. From this, the triage nurse determines the ATS and urgency of initial treatment. It is also helpful to determine if the patient is known to a mental health service.

Table 20.1.2 The Mental Health Triage Scale

ATS 2	Patient is violent, aggressive or suicidal, or is a danger to self or others
	Requires police escort/restraint
ATS 3	Very distressed or acutely psychotic
	Likely to become aggressive
	May be a danger to self or others
ATS 4	Long-standing or semi-urgent mental health problem and/or has supporting agency/escort present
ATS 5	Patient has a long-standing non-acute mental health disorder but has no support agency
	Many require referral to an appropriate community resource

Many centres have developed a triage risk assessment proforma. For ease of use, many of these have included ‘tick box’ areas. A compilation of multiple assessment tools used throughout Australia is shown in Tables 20.1.3, 20.1.4 and 20.1.5.^{1,2,3,5,11,12}

Table 20.1.3 Brief screening suicide risk template

Mental state	Active disease
	Depression
	Psychosis
	Hopelessness/despair/guilt/shame
	Anger/agitation
	Impulsivity
Suicide attempts/thoughts	Continual/specific thoughts
	Formulated plan
	Intent
	Past history of attempt with high lethality
	Means
	Suicide note
	Risk of being found
	Organizing personal affairs
Substance abuse	Current misuse
Supports	Lack of or hostile relationships
Loss	Recent major loss (even perceived): significant relationship, job, housing, financial difficulties, independence
	Recent/new diagnosis of major illness or chronic illness
Patients then stratified into high, medium or low risk

Table 20.1.4 Aggression risk tool

Alert on chart

Previous history of violence/threatening behaviour: verbal or physical

Aggressive behaviour/thoughts

Homicidal ideation

Use of weapons previously

Access to weapons

Intoxicated

Middle aged male

Patient then stratified into high, medium or low risk

Table 20.1.5 Risk of absconding

Mode of arrival

Police

Handcuffed

Family/carer coercion

Voluntary

Past history of absconding behaviour

Alert on chart

Verbalising intent to leave

Lack of insight into illness

Poor/non-compliance with medication

Patients then stratified into high, medium or low risk

It is recommended that any patient who scores ‘high risk’ in any one area or ‘medium risk’ in two areas is treated as a ‘high risk’ patient. Ensuing management of ‘high risk’ patients depends on: local protocols, levels and presence of security, police intervention, restraint and sedation guidelines and guidelines for the urgent assessment by ED and/or by mental health services.

Aims of mental health assessment

The aims of the formal mental health assessment are to determine the following:

Only if all of the above are answered, can management and appropriate disposition be considered.

The formal psychiatric interview

The process of obtaining a mental health assessment is different to that of a general medical assessment. In a general medical history, a series of questions is asked and the response is written. In a mental health assessment, responses are also interpreted. The interviewer is asked to form an opinion as to how thoughts are processed, based on observations. The interviewer is asked to interpret the patient’s thought patterns by what and how the patient tells the interviewer.

Presenting complaint

The patient is asked to recall the sequence of events prior to presentation to the ED. The interviewer should explore the circumstances of the behaviour, reasons for it, degree of planning or impulsivity, and its context. Were drugs and alcohol involved? Was there a recent precipitating event? It is often useful to get the patient to recall the previous 48–72 h leading up to the event.

This usually leads to questioning regarding current difficulties. The interviewer should explore the nature of current problems. They may be financial or legal problems, isolation, bereavement, impending or actual loss, or diagnosis of major illness. Have there been any recent changes and who are their usual support people/person? An exploration of significant relationships is important along with the depth and duration of these relationships. It is useful to explore the patient’s usual coping methods when under stress.

Mood and affect

There should be formal questioning regarding the patient’s mood (internal feelings) and whether it is in keeping with affect (external expression). The mood may be incongruent with affect, swing wildly between extremes (labile) or be completely inappropriate.

Usually mood is assessed by asking about the patient’s ability to cope with activities of daily living such as eating, weight loss or gain, sleep disturbance (early morning wakening or trouble getting to sleep) and general hygiene. The patient’s ability to concentrate may also diminish with increasing mood disturbance, reflected by the ability to perform normal work duties.

This may lead to direct questioning regarding mood and thoughts of suicide. It is important to be direct in asking the patient about suicide and whether they have a formulated plan. A well thought out plan with clear means of carrying out threats is of great concern.

Delusions and hallucinations

Delusions and hallucinations are often personal and the patient may not want to disclose intimate thoughts and beliefs to the interviewer. Hallucinations may be auditory, visual, tactile, olfactory, somatic or gustatory. The context in which they occur should be explored. Hypnagogic (occurring just before sleep) and hypnopompic (occurring on wakening) hallucinations are more benign than others. Common themes for all types of hallucinations include suicide, persecution, religion, control, reference, grandeur or somatization.

Insight and judgement

Insight is the degree of understanding of what is happening and why. This may be:

It is important to determine the patient’s level of insight. This determines appropriate treatment and management, level of supervision required and the likelihood of compliance with treatment.

Introduction

Emergency physicians are facing a significantly increased volume and complexity of mental disorder presentations. Increased numbers relate to increased community care for chronic mental illness, the ageing population and frequent substance abuse. Intoxicated patients, with and without mental disorder, are increasingly being presented to emergency departments (EDs) for assessment due to concerns about patient or community safety. These patients frequently display impulsive, suicidal or violent behaviour and are often difficult to manage. A thorough understanding of the assessment and appropriate disposition of mental disorder presentations is essential for all emergency physicians.

The concept of differentiating an organic from a psychiatric basis for a mental disorder is becoming increasingly blurred as research shows the biological and genetic basis of many traditional psychiatric illnesses. The accepted terminology for classification of mental disorder is also rapidly changing. One accepted Western standard is the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV).¹ To emphasize the biological basis of many traditional psychiatric illnesses, DSM-IV no longer uses the term ‘organic mental disorder’. Despite this change, current clinical management and disposition still revolve around the traditional distinction of organic (medical) from psychiatric problems.

In practice emergency physicians need a simple classification defining the principal diagnosis of the presenting mental disorder consistent with current DSM-IV terminology. This should assist diagnostic, management and disposition accuracy. Table 20.2.1 is such a suggested classification. A more simplistic grouping into psychiatric, medical, substance-related or anti-social behaviour may even suffice. Correct assignment by the emergency physician to the appropriate classification, and hence appropriate disposition, reduces medical costs and morbidity.²

Table 20.2.1 A simple classification of principal diagnosis of mental disorder for emergency physicians

General approach

Patients with abnormal behaviour labelled as psychiatric after routine medical and psychiatric assessment frequently have a final diagnosis of a medical cause or precipitant for the mental disorder. The incidence of missed medical diagnosis ranges between 8 and 46%.^2–4 A prospective study of ED patients in the USA showed a medical diagnosis in 63% of patients with first psychiatric presentations.⁵ Deciding whether a particular presentation of mental disorder is medical or psychiatric is often difficult, as there are very few absolutes that distinguish medical from psychiatric illness. Careful collection and weighing of appropriate information commonly leads to an accurate differential diagnosis.

Some diagnoses and dispositions can be determined quickly after a medical and psychiatric history, with the addition of a mental state and full physical examination. This may sometimes take place without expensive diagnostic procedures.⁶ Other presentations are difficult and require extensive and intensive evaluation, repeat evaluation, observation in hospital and significant investigations before the diagnosis is clear.

Many initial assessments in EDs are difficult and inaccurate owing to the presence of intoxicating substances or difficult patient factors. The latter may include poor communication ability, poor cooperation with examination, antisocial behaviour, intentional obscuring of information or denial of problems. Intoxicated patients may have other complex and distracting issues, such as threats of violence or self-harm, possible head injury, possible unknown substance overdose, and poor cooperation with necessary history, examination and investigations. A non-judgemental approach with prudent intervention based on known or likely risks, close monitoring in a safe environment, and repeated reassessment of physical and mental state over time are necessary to obtain an accurate diagnosis and optimal outcome.

Studies on medical clearance by ED staff, primary-care physicians and psychiatrists have repeatedly shown a poor ability to discover medical conditions. This failure is commonly due to one or more of the following factors: inadequate history, failure to seek alternative information from relatives, carers and old records, poor attention to physical examination, including vital signs, absence of a reasonable mental state examination, uncritical acceptance of medical clearance by receiving psychiatric staff and failure to re-evaluate over time.⁷ A recent study noted that medical conditions were most easily identified in the ED by the triage nurse or medical officer asking whether any medical conditions existed in addition to the patient’s psychiatric complaints.⁸

Conversely, studies have shown that many patients admitted with a medical diagnosis frequently have a physical presentation of a classic psychiatric disorder. In addition, patients who frequently present to EDs with physical problems commonly have abnormal illness behaviour. Inability to recognize this leads to inappropriate diagnosis and management, with subsequent treatment failure.

Psychiatric patients also have a higher incidence of physical illness than the general population. The comorbid illness may not have been diagnosed previously in this socially disadvantaged population.

Evaluation requires a thorough approach and a commitment of time and effort. Special skills are required for medical clearance and psychiatric interview. A coordinated and focused medical and psychiatric assessment has the highest yield of correct diagnoses.² Proformas may improve compliance and documentation of important details.

Triage

Triage is vital, as many patients presenting with apparent psychiatric problems have medical conditions. The patient previously labelled psychiatric must be carefully triaged to avoid any new medical problems being overlooked. Psychiatric patients have been found to express their physical illnesses in different ways from those without mental illness. They may be suffering from severe or life-threatening illness, but fail to communicate this to their medical carers. Correct identification at the point of entry by nursing staff facilitates correct management and reduces morbidity and mortality.⁹ Many patients with psychiatric illness are also a significant risk to themselves or others, and require urgent intervention. Questions regarding safety should always be raised¹⁰ (Table 20.2.2).

Table 20.2.2 Triage safety questions¹⁰

Nursing staff should use a triage checklist to identify likely organic presentations (Table 20.2.3). These are indications for urgent medical assessment. If these are absent and a psychiatric diagnosis is likely, then an appropriate urgency rating by Australasian Triage Scale for psychiatric presentations should be applied. This triage categorization for psychiatric presentations has been developed and verified, and allows reasonable waiting time standards for urgency to be applied (Table 20.2.4).¹¹

Table 20.2.3 High-yield indicators of organic illness

Introduction

Suicide is a deliberate act of intentional self-inflicted death. It is the most extreme expression of suicidality, which also comprises suicidal thoughts, threats, planning and attempted suicide through deliberate self-harm (DSH). Although suicide is uncommon, 10% of people who commit suicide are seen in an emergency department (ED) in the month prior to death, with a substantial proportion not having psychosocial assessment, thus providing an opportunity for intervention.^1,2 The major ED impact, however, is in the assessment of large numbers of potentially suicidal patients, accurate risk stratification, and initial control and management of these patients.

DSH is a maladaptive response to stress and a manifestation of suicidality, but can also occur without any intent to die with other psychiatric and personality disorders.³ Deliberate self-harm is a common ED presentation (approximately 0.5% of all ED visits⁴) and the goals of management include treatment of the physical sequelae, assessment of risk of non-fatal or fatal repetition, and diagnosing and commencing treatment of potentially reversible psycho-social causes.⁵

Incidence

In Australia there were approx 2100 deaths per year from suicide in 2004 and 2005, with age-standardized rates of approximately 16.4 per 100 000 in males and 4.3 in females.⁶ Suicide accounts for 1.6% of deaths in Australia and is in the top 10 causes of death despite a reduction of approximately 30% in suicide rates from 1997 to 2004.⁷ Suicide rates are similar in the UK, New Zealand, Canada and the USA, suicide accounting for 1–2% of all deaths in these countries.^6,8–11 The national rates of suicide vary: Japan, Scandinavian and Eastern European countries have population suicide rates as high as 25:100 000, whereas some southern European and Middle Eastern countries have rates less than 5:100 000.^11,12

Hospital presentations for DSH are at least 10 times higher than suicide rates.^6,9 In the 1997 Australian National Survey of Mental Health, 0.3% of males and 0.4% of females reported they had made a suicide attempt in the previous 12 months. Most of these are not reported or are reported as accidents. Hence unrecognized DSH is at least as frequent as that recognized. The same survey reported 2.7% of males and 4.5% of females experienced suicidal thoughts within 12 months.¹³ This rate may be as high as 25% in certain populations and age groups.^14,15

Aetiology

No specific psychological or personality structure is associated with suicide, and patients who commit suicide or DSH do so for many unrelated reasons. The precipitant may be a personal crisis or life change amplified by poor social support, substance abuse or psychiatric disorder. Intoxication may decrease inhibitions enough to allow an act to proceed.

The most frequent methods of suicide in Australia are hanging (approximately 50% of male and 40% of female suicide deaths) and deliberate self-poisoning (approximately 30% of males and 40% of females). Firearms accounted for 7% of suicide deaths in Australia in 2005, a rate which has declined from 20% a decade prior, possibly due to firearm restriction legislation.⁶ Proportions due to each method vary according to region, residence, age and sex.^1,16 In the USA, firearms accounted for 57% of male and 32% of female suicide deaths. In many developing countries, organophosphate or antimalarial poisoning is the most common method of suicide.^17,18

One-third of patients with DSH express a wish to die, but most seek attention or want to communicate distress. Other reasons include release of tension, escape from a stressful situation, blotting out distressing thoughts, eliciting guilt, manipulating others, expressing anger or grief, or escaping from custody. Many patients threaten suicide or exaggerate suicidality to increase the likelihood of admission to hospital. These patients are more likely to be substance dependent, antisocial, homeless, unmarried and in legal difficulty. However, these instances of secondary gain should not be assumed to be the cause of the suicidality and the behaviour should be taken seriously.

Most cases of medically serious DSH are due to self-poisoning, with 90% associated with alcohol intoxication. The most common drugs are non-prescription analgesics and psychotropic drugs. Many overdoses are related to recreational drug use and may be accidental rather than deliberate, although this distinction is often difficult. Self-injury usually involves cutting of the wrist or forearm. Some people self-inflict cigarette burns, excoriate their skin or hit themselves. More violent forms of self-injury are less common and suggest serious suicidal intent. Bizarre self-mutilation may occur in psychotic patients who may not necessarily have an intention to die. Self-immolation, suicide bombing and hunger striking as forms of protest are special concerns.

Patient characteristics

Assessment

A person who expresses suicidal ideation or commits an act of DSH is sending a distress signal that emergency physicians must recognize and assess for further risk. Suicidality should also be assessed in patients with symptoms or signs of depression, unusual behavioural changes, substance abuse, psychiatric disorders, complainants of sexual violence,²⁸ and those who present with injuries of questionable or inconsistent mechanism, such as self-inflicted lacerations and gunshot wounds or motor vehicle accidents involving one victim.

Assessment requires a systematic, multidisciplinary approach involving prior staff education, appropriate triage, observation and restraint procedures, and a planned strategy for assessment followed by treatment and disposition. The priorities are to define the physical sequelae of the act, risk of further suicidal behaviour, psychiatric diagnoses and acute psycho-social stressors. These aspects are those that can then be targeted for short-term interventions.

Definitive treatment and disposition

Following necessary medical treatment and suicide-risk stratification, disposition may involve involuntary or voluntary admission to a psychiatric or medical ward, short-term or overnight observation, or discharge with appropriate follow-up. Restraint and involuntary admission may be necessary for the high-risk patient who wishes to self-discharge. Approximately 30% of DSH patients are admitted for psychiatric inpatient care but the factors involved in the decision for psychiatric hospitalization following DSH are not well understood and involve a complex evaluation of risk, potential for treatment and social supports.³⁷

Overnight observation allows drug intoxication to resolve so that proper psychiatric assessment can take place. An overnight stay in hospital can also help resolution of many acute areas of conflict and make psychiatric evaluation more accurate. ED short-stay wards are appropriate for these admissions, especially if a multi-disciplinary team is available to review the patient and institute management and follow-up.

Important elements of management involve neutralizing the precipitating problem, treatment of psychiatric illness and environmental interventions such as family counselling, encouraging a support network, and developing coping and problem-solving skills.³⁸ Open discussion about suicide should be undertaken and a firm stance should be maintained that suicide is an ineffective solution. Alternative, non-suicide solutions should be reinforced. Other factors that should be addressed whilst patients are in hospital include problems with relationships, employment, finances, housing, legal problems, social isolation, alcohol and drug abuse, and bereavement. In this regard, medical social workers or mental health nurses are invaluable.³⁹ For greatest effect, these should be available after hours and on weekends since the majority of DSH presents after hours.⁴⁰ For repeat attenders or manipulative patients who are often socially isolated, hospitalization should not be a substitute for social services, substance-abuse treatment and legal assistance, although admission may be necessary while appropriate supports are put in place.⁴¹

Discharge is appropriate for the low-risk patient who is cooperative, no longer suicidal, not intoxicated, has no underlying psychiatric or substance abuse disorder, and has strong social support with the precipitating problem having resolved due to the act or subsequent assessment and intervention in hospital. Discharged patients should make a commitment to seek help if they reach a crisis point, and the physician should be available to help. This can be part of a commitment to a non-suicidal behavioural plan between the patient and clinician. This contract should be with the clinician who will arrange definitive care. Contracts may delay the patient’s suicidal impulses so that other treatment strategies can be implemented. If discharged, there should be liaison with the patient’s general practitioner and therapist, and follow-up should be confirmed where possible within 1–2 days.

Pharmacotherapy involves the treatment of the underlying psychiatric disorder. Antidepressants decrease the risk of attempting suicide, although the lethality of suicide attempts is increased if tricyclic antidepressants are taken in overdose. Selective serotonin reuptake inhibitors may have a more selective effect in decreasing suicidal behaviour and are less toxic in overdose. These factors make this class of drugs an attractive choice for depressed patients who are suicidal, but any long-term therapeutic drug should, ideally, be prescribed by the doctor who will provide definitive follow-up.⁴²

Consequences

Prevention

Comprehensive strategies for prevention of suicide have been or are being developed in Finland, Norway, Sweden, Australia and New Zealand.¹² Suicide prevention focuses on psychiatric, social and medical aspects, and usually involves public education, media restrictions on reporting of suicide, school-based programmes with teacher education, training of doctors in detection and treatment of depression and other psychiatric disorders, alcohol and drug-abuse information, enhanced access to the mental health system and supportive counselling after episodes of DSH. Decreasing the availability of lethal methods may involve legislative changes such as more stringent gun control, restricting access to well-known jumping sites or changes to availability or packaging of tablets.⁵⁷ Overall, studies into the effectiveness of suicide-prevention strategies have shown inconsistent reductions in suicide rates following interventions.⁵⁸ Approaches to reduce DSH repetition have also shown disappointing results.⁵⁹ Improved recognition and treatment of mental illness, improved social services, and drug- and alcohol-support services may be of greater benefit than specific suicide-prevention strategies.

Conclusion

Assessment of suicide risk is an important skill in emergency medicine since many patients present to EDs with suicidal thinking or behaviour. Although the risk of suicide for an individual patient is remote and cannot be predicted, emergency physicians can provide a system for assessment and identification of risk groups. Acute interventions can attempt to prevent short-term completion of suicide or repetition of DSH, since emergency physicians are predominantly involved in the care of these patients, often using short-stay wards. A team approach involving psychiatry and social work is necessary in most cases, with many minor problems resolved by a short-term hospital admission, brief crisis intervention and intense short-term follow-up.

Introduction

The need to determine the presence and severity of a depressive syndrome is a very frequent task in the emergency department (ED). Assessment of depression is necessary in relation to a variety of patient presentations. The classic ED situation is the overdose, or other attempted suicide or self-harm, where the assessment of depression forms part of further evaluation after the patient has been medically stabilized. It is also becoming more common for patients to present to the ED complaining of depression (often on the advice of family, friends or crisis helplines) without having harmed themselves. Patients with a variety of medical conditions, especially conditions which are chronic or disabling, also often develop a depressive syndrome that can form a major part of the reason behind an ED attendance. Some patients who present to EDs with personal crisis or self-harm may have been identified as suffering from a personality disorder, but nevertheless need assessment for comorbid depression. The evaluation of depressive symptoms is also an important aspect of the assessment of patients seen in the ED with alcohol and drug abuse problems.

In these assessments it is very important to have a clear concept of the syndrome of ‘clinical depression’. This syndrome is called ‘depressive episode’ in The International Classification of Disease – 10th edition¹ (ICD-10) and ‘major depression’ in the Diagnostic and Statistical Manual of Mental Disorders – 4th edition² (DSM-IV). The importance of diagnosing a depressive episode lies principally in determining the presence of a clinical syndrome which is in need of treatment, is likely to respond to treatment and is likely to persist without treatment. The clear delineation of a depressive episode is also an essential basis for differential diagnosis from other medical and psychiatric conditions, and for distinguishing between the clinical syndrome of depression and the day-to-day fluctuations of mood and states of dejection, pessimism, frustration and disappointment which are the lot of all human beings.

The diagnosis of a depressive episode depends on the pervasive presence of a sufficient number of a specific list of symptoms. The list of symptoms contributing to the depressive episode syndrome in ICD-10 is shown in Table 20.4.1. The DSM-IV syndrome of major depression has the same list of symptoms, with the exception of ‘loss of confidence or self-esteem’. An adequate number of these symptoms must be present for at least 2 weeks before the diagnosis of depressive episode can be made. The pervasiveness of the symptoms is defined principally by the specifications that they must be present ‘most of the day’ and for ‘nearly every day’.

Table 20.4.1 Symptoms contributing to the diagnosis of a depressive episode in ICD-10¹

ICD-10 further classifies depressive episodes into mild, moderate and severe, according to the total number of symptoms present (mild = 4/10 symptoms, moderate = 6/10 symptoms and severe = 8/10 symptoms). However, it is important to note that both the mild and moderate categories require the presence of at least two of the first three symptoms, that is the patient must have two of depressed mood, loss of interest or loss of energy, most of the day, nearly every day, for at least 2 weeks. The diagnosis of severe depressive episode requires the presence of all three of the first three symptoms.

The diagnosis of a depressive episode does not in any way depend on the presence or absence of a precipitating life event or situation. The ICD-10 also has a category of brief depressive reaction (one of the ‘adjustment disorders’), which forms part of the differential diagnosis of a depressive episode. This syndrome is defined by the presence of a precipitating life event and depressive symptoms. However, if the depressive symptoms are of sufficient number, pervasiveness and duration as to qualify for the description of a depressive episode, then this diagnosis should be made regardless of the presence of a precipitant. The notion that ‘this patient’s depression is understandable given the circumstances’ should never detract from a proper evaluation of the severity and duration of the symptoms.

It is an ICD-10 requirement that depressive syndromes which form part of a bipolar disorder, or are secondary to alcohol or other drug abuse or to a medical condition, should be given a different diagnostic category (‘bipolar affective episode, current episode mild, moderate or severe depression’, ‘mood disorder due to psychoactive substance use’ or ‘organic mood disorder’). The distinction is important because the treatment implications may be significant.

Epidemiology

Clinical depression, defined as ‘major depression’ or an ICD-10 ‘depressive episode’, is a very common condition. Extensive epidemiological community surveys in many populations around the world have established that the 6-month prevalence rate of major depression is in the range of 2–5% in any population.³ The epidemiological research has also shown that only a minority of persons with current depressive syndromes are receiving active treatment.³

The age onset of the first depressive episode is typically in the third decade, but can be at any age. The male to female ratio is 1:2. A person who has had one episode of clinical depression has an 80% chance of recurrence, and patients with recurrent depression have an average of four episodes in their lifetime.⁴

Incomplete recovery is common. Studies of hospitalized patients have shown that, while at least 50% of patients recover from an index episode within 6 months, 30% remain symptomatic for more than a year and 12% for more than 5 years.⁵

There is some evidence for an increase in the prevalence of major depression, and a younger age of onset, over the last 40 years.⁶

Aetiology

The aetiology of depression is complex, involving both genetic and environmental factors. Important environmental factors include childhood experiences of adversity or neglect, and stresses in adult life. The effect of genetic factors may be mediated in part through inherited predispositions to excessive worry and anxiety.³

Precipitating life events, especially those involving loss, are known to play a part in triggering individual episodes of depression.⁷ This effect is greatest for the first episode of depression. Second and subsequent episodes are more likely to occur without identifiable precipitating events,⁸ suggesting that the first episode has a neurobiological priming effect.⁹

Neurobiological changes in depression are also complex. Based in part on the supposed mechanism of action of antidepressant medication, early work focused on evidence of depletion of amine neurotransmitters in the central nervous system.¹⁰ More recent research has suggested depression may involve alterations in neural cell populations, especially in the hippocampus.¹¹

Prevention

Depression is a major public health problem. The World Health Organization has determined that in 1990 depression was the fourth leading cause of disease burden in the world and that by 2020 it would be the second leading cause of disease burden.¹² Public health measures have included campaigns to raise awareness of depression both in the general public and in healthcare providers. ED staff can play a very significant role in case identification and in ensuring referral for effective treatment.

Clinical features

The syndrome described as a ‘depressive episode’ (or ‘major depression’) is defined principally by its symptoms and, to a lesser extent, signs. As the severity of the depressive episode is also dependent on specific characteristics of the individual symptoms and signs (as well as the total number of symptoms) it is also important to understand the varieties of their manifestations.

Differential diagnosis

The differential diagnosis of the depressive syndrome is important because there are several other clinical disorders involving depressed mood or other symptoms of depression which have a different prognosis and treatment.

Assessment

The assessment of the patient for depression should cover:

It is generally a good idea to start the interview with some basic social information. Does the patient live alone? How is he or she occupied or employed? Is there a supportive relationship or other family? This information assists in understanding the context of the symptoms and helps with treatment planning.

Exploration of precipitating events is important partly because these worries are likely to be occupying the mind of the patient and discussion of these issues helps to build rapport in the interview.

Identification of the presence and severity of the depressive symptoms is the most important part of the assessment. Unfortunately, it is often not done systematically and the ‘diagnosis’ of depression is made only on the basis of a patient’s statement about ‘being depressed’ and one or two other symptoms such as sleep and appetite disturbance. Systematic evaluation requires detailed exploration of the symptoms described above. Particular attention should be paid to the persistence, pervasiveness and duration of the symptoms. If this systematic approach is taken it is possible to determine:

The proper diagnosis of a depressive syndrome and the assessment of the severity of the syndrome are of major importance in treatment planning.

There may be insufficient time in an emergency interview to explore fully the previous psychiatric history. However, it is useful to ask if the patient has been depressed before, whether or not any previous episodes were treated and what was the response to previous treatment. It is also important to identify any previous episodes of mania in case the depressive episode may be a presentation of bipolar disorder.

Mental state examination focuses on the signs described above. Persistently sad affect and noticeable psychomotor agitation or retardation are indicators of more severe depression. Similarly, if the patient’s conversation is very preoccupied with themes of failure, despair, guilt or death the depression is likely to be more severe. Inquiry about these matters should be extended to look for delusional beliefs. Useful questions may include ‘Do you feel responsible for bad things happening?’, ‘Do you feel there is something drastically wrong with you?’ or ‘Do you believe you deserve punishment?’. Understanding the patient’s level of insight into his or her condition is also important to treatment planning, particularly if involuntary treatment should become necessary due to the risk of suicide.

Risk assessment is multi-faceted. If the patient has attempted suicide through overdose or other means, inquiry should be made about the circumstances of this attempt, the patient’s understanding of the lethality of the attempt and whether or not the patient sought help afterwards or made an effort to conceal the attempt. The patient’s current thoughts about suicide and his or her attitude to suicide are also relevant. Many patients admit to having thoughts of suicide but indicate that they would be deterred from suicidal action by, for example, having responsibility for dependent children. The disappearance of these ‘protective factors’ from a patient’s considerations is an indicator of worsening risk. Patients with psychotic depression may be at higher risk because they lack such ‘emotional’ constraints on suicidal behaviour. Other factors associated with increased suicide risk include lack of supportive relationship, living alone, being unemployed and current alcohol abuse.

A primary medical condition causing depressive symptoms is likely to be suggested by other symptoms and signs, or be pre-existing. There are no mandatory investigations for the assessment of a depressive episode, although checking thyroid biochemistry is sensible.

Inquiry should be made about alcohol and other drug-use patterns, and especially recent changes in pattern use. A person with long-standing alcohol or other drug abuse is likely to have a substance-induced mood disorder, and needs to address this as the major focus of treatment. A recent marked increase in alcohol or other drug use may indicate an attempt to self-medicate for a depressive syndrome.

It is always useful to ask the patient if she or he is currently seeing a psychiatrist, psychologist or other mental health therapist, or has a good relationship with a trusted GP. These existing healthcare professionals can often be the natural starting point in planning treatment interventions.

Treatment

Treatment for a depressive episode involves the prescription of specific antidepressant medication or a specific course of psychotherapy or both.