Introduction

The next two chapters describe depressive disorders and bipolar disorder. These conditions are also called mood disorders because one of their main features is abnormality of mood. Nowadays the term is usually restricted to disorders in which this mood is depression or elation, but in the past some authors have included states of anxiety as well. In this book, anxiety disorders are described in Chapter 8. Mood disorders have in the past been referred to as ‘affective disorders’, a term that is still used fairly widely.

Depressive disorders

It is part of normal experience to feel unhappy during times of adversity. The symptom of depressed mood is a component of many psychiatric syndromes, and is also

commonly found in certain physical diseases (e.g. in infections such as viral hepatitis, and some neurological disorders). In this chapter we are concerned neither with normal feelings of unhappiness nor with depressed mood as a symptom of other disorders, but with the syndromes known as depressive disorders.

The central features of these syndromes are:

● depressed mood

● negative thinking

● lack of enjoyment

● reduced energy

● slowness.

Of these, depressed mood is usually, but not invariably, the most prominent symptom.

 

Clinical features

Depressive syndromes

The clinical presentations of depressive states are varied, and they can be subdivided in a number of different

ways. In the following account, disorders are grouped by their severity. The account begins with a description of the clinical features of an episode of severe depression, together with certain important clinical variants that can influence the presentation of depressive disorders. Finally, the special features of the less severe depressive disorders are outlined. What constitutes an ‘episode’ of clinical depression is inevitably a somewhat arbitrary concept. The symptoms listed for the diagnosis of ‘depressive episode’ in the ICD-10 classification and the various levels of severity are shown in Box 9.1. Similar symptoms (five or more) are required for the diagnosis of ‘major depressive episode’ in DSM-5 except that the symptomatology in DSM-5 includes psychomotor agitation or retardation. DSM-5 also specifically requires that the symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Severe depressive episode

In a severe episode of depression, the central features are low mood, lack of enjoyment (anhedonia), negative thinking, a nd reduced energy, all of which lead to decreased social and occupational functioning.

Appearance

The patient’s appearance is characteristic. Dress and grooming may be neglected. The facial features are characterized by a turning downward of the corners of the mouth, and by vertical furrowing of the centre of the brow. The rate of blinking may be reduced. The shoulders are bent and the head is inclined forward so that the direction of gaze is downward. Gestures and movements are reduced. It is important to note that some patients maintain a smiling exterior despite deep feelings of depression.

Mood

The mood of the patient is one of misery. This mood does not improve substantially in circumstances where ordinary feelings of sadness would be alleviated—for example, in pleasant company or after hearing good news. The low mood is, in this sense, pervasive. Moreover, the mood is often experienced as different from ordinary sadness. Patients sometimes speak of a black cloud pervading all mental activities. Some patients can conceal this mood change from other people, at least for short periods. Some try to hide their low mood during clinical interviews, which makes it more difficult for the doctor to detect. The mood is often worse first thing in the morning when the patient wakes, improving as the day wears on. This is called diurnal variation of mood.

Depressive cognitions

Negative thoughts (‘depressive cognitions’) are important symptoms that can be divided into three groups:

● worthlessness

● pessimism

● guilt.

In feeling worthless, patients think that they are failing in what they do and that other people see them as a failure; they no longer feel confident, and discount any success as a chance happening for which they can take no credit. Pessimistic thoughts concern future prospects. Patients expect the worst. They foresee failure in work, the ruin of finances, misfortune for family, and an inevitable deterioration in health. These ideas of hopelessness are often accompanied by the thought that life is no longer worth living and that death would come as a welcome release. These gloomy preoccupations may progress to thoughts of, and plans for, suicide. It is important to ask about these ideas in every case Feelings of guilt often take the form of unreasonable

self-blame about minor matters—for example, patients

may feel guilty about past trivial acts of dishonesty or

letting someone down. Usually these events have not

been in patients’ thoughts for years, but when they

become depressed they flood back into their memory, accompanied by intense feelings. Preoccupations

of this kind strongly suggest depressive disorder. Some

patients have similar feelings of guilt but do not attach

them to any particular event. Other memories are

focused on unhappy events; patients remember occasions when they were sad, when they failed, or when

their fortunes were at a low ebb. These gloomy memories become increasingly frequent as the depression

deepens. Patients blame themselves for their misery

and incapacity, and attribute it to personal failing and

moral weakness (a view not uncommonly held by the

wider public).

Goal-directed behaviour

Lack of interest and enjoyment (also known as anhedonia) is

frequent, although it is not always complained of spontaneously. Patients show no enthusiasm for activities

and hobbies that they would normally enjoy. They feel

no zest for living and no pleasure in everyday things.

They often withdraw from social encounters. Reduced

energy is characteristic (although depression is sometimes associated with a degree of physical restlessness

that can mislead the observer). Patients feel lethargic,

find everything an effort, and leave tasks unfinished. For

example, a normally house-proud person may leave the

beds unmade and dirty plates on the table. Work outside

the home becomes increasingly difficult and academic

achievement declines. Understandably, many patients

attribute this lack of energy to physical illness. Anhedonia

is an important symptom because it is an important way

of distinguishing depression of at least moderate severity

from milder disorders. It is also a key symptom of melancholic depression (see ‘Classification by symptomatic

picture’ below).

Psychomotor changes

Psychomotor retardation is frequent (although, as

described later, some patients are agitated rather than

slowed down). The retarded patient walks and acts

slowly. Slowing of thought is reflected in their speech;

there is a significant delay before questions are answered,

and pauses in conversation may be unusually prolonged.

Agitation is a state of restlessness that is experienced

by the patient as inability to relax, and is seen by an

observer as restless activity. When it is mild, patients are

seen to be plucking at their fingers and making restless

movements of their legs; when it is severe, they cannot

sit for long, and instead pace up and down.

Anxiety is frequent, although not invariably present,

in severe depression. (As described later, it is common

in less severe depressive disorders.) Another common

symptom is irritability, which is the tendency to respond

with undue annoyance to minor demands and frustrations, and can be a core presenting feature in adolescents

in particular.

Biological symptoms

There is an important group of symptoms that is often

described as ‘biological’ (also referred to as ‘melancholic’,

‘somatic’, or ‘vegetative’). These symptoms include sleep

disturbance, diurnal variation in mood, loss of appetite, loss

of weight, constipation, loss of libido, and, among women,

amenorrhoea. They are very common in depressive disorders of more severe degree (but less usual in mild depressive disorders). Some of these symptoms require further

comment.

Sleep disturbance in depressive disorders is of several kinds. The most characteristic type is early-morning

waking, but delay in falling asleep and waking during

the night also occur. Early-morning waking occurs 2 or

3 hours before the patient’s usual time of waking. He

does not fall asleep again, but lies awake feeling unrefreshed and often restless and agitated. He thinks about

the coming day with pessimism, broods about past failures, and ponders gloomily about the future. It is this

combination of early waking and depressive thinking that

is important in diagnosis. It should be noted that some

depressed patients sleep excessively rather than waking

early, but they still report waking unrefreshed.

Weight loss in depressive disorders often seems to be

greater than can be accounted for merely by the patient’s

reported lack of appetite. In some patients the disturbances of eating and weight are towards excess—that is,

they eat more than usual and gain weight. Usually eating brings temporary relief of their distressing feelings.

Complaints about physical symptoms are common in

depressive disorders. They take many forms, but complaints of constipation, fatigue, and aching discomfort anywhere in the body are particularly common.

Complaints about any pre-existing physical disorder

usually increase, and hypochondriacal preoccupations are

common.

Other features

Several other psychiatric symptoms may occur as part

of a depressive disorder, and occasionally one of them

dominates the clinical picture. They include depersonalization, obsessional symptoms, panic attacks, and more rarely, dissociative symptoms such as fugue or loss of function of a limb. Complaints of poor memory are also common; depressed patients commonly show deficits on a wide range of neuropsychological tasks, but impairments in the retrieval and recognition of recently learned material are particularly prominent. Sometimes the impairment of memory in a depressed patient is so severe that the clinical presentation resembles that of dementia. This presentation, which is particularly common in the elderly, is sometimes called depressive pseudodementia (Chapter 14).

Psychotic depression

As depressive disorders become increasingly severe, all of the features described above occur with greater intensity. There is complete loss of function in social and occupational spheres. Inattention to basic hygiene and nutrition may give rise to concern about the patient’s wellbeing. Psychomotor retardation may make interviewing difficult or impossible. In addition, there may be delusions and hallucinations, in which case the disorder is referred to as psychotic depression (depressive psychosis is a synonym). As with other psychotic states, insight is impaired and patients (usually of blameless character) regard themselves as wicked and being justly punished for their misdeeds.

The delusions of severe depressive disorders are concerned with the same themes as the non-delusional thinking of moderate depressive disorders. Therefore they are termed mood-congruent. These themes are worthlessness, guilt, ill health, and, more rarely, poverty. Such delusions have been described in Chapter 1, but a few examples may be helpful at this point. Patients with a delusion of guilt may believe that some dishonest act, such as a minor concealment when filling in a tax return, will be discovered and that they will be punished severely and humiliated. They are likely to believe that such punishment is deserved. Patients with hypochondriacal delusions may be convinced that they have cancer or venereal disease, while patients with a delusion of impoverishment may wrongly believe that they have lost all of their money in a business venture.

Persecutory delusions also occur. Patients may believe that other people are discussing them in a derogatory way or are about to take revenge on them. When persecutory delusions are part of a depressive syndrome, typically patients accept the supposed persecution as something that they have brought upon themselves. In their view, they are ultimately to blame. This can be a useful diagnostic feature for distinguishing severe depression from non-affective psychosis (see Chapter 11). Some depressed patients experience delusions and

hallucinations that are not clearly related to themes of depression (i.e. they are ‘mood-incongruent’). Their presence appears to worsen the prognosis of the illness.

Particularly severe depressive delusions are found in Cotard’s syndrome, which was described by the French psychiatrist, Jules Cotard, in 1882. The characteristic feature is an extreme kind of nihilistic delusion. For example, some patients may complain that their bowels have been destroyed, so they will never be able to pass faeces again. Others may assert that they are penniless and have no prospect of ever having any money again. Still others may be convinced that their whole family has ceased to exist and that they themselves are dead. Although the extreme nature of these symptoms is striking, such cases do not appear to differ in important ways from other severe depressive disorders.

Other clinical variants of depressive disorders

Agitated depression

This term is applied to depressive disorders in which agitation is prominent. As already noted, agitation occurs in many severe depressive disorders, but in agitated depression it is particularly severe. Agitated depression is seen more commonly among middle-aged and elderly patients than among younger individuals.

Retarded depression

This name is sometimes applied to depressive disorders in which psychomotor retardation is especially prominent. There is no evidence that they represent a separate syndrome, although the presence of prominent retardation is said to predict a good response to electroconvulsive therapy (ECT). If the term is used, it should be in a purely descriptive sense. In its most severe form, retarded depression merges with depressive stupor.

Depressive stupor

In severe depressive disorder, slowing of movement and poverty of speech may become so extreme that the patient is motionless and mute. Such depressive stupor is rarely seen now that active treatment is available. Therefore the description by Kraepelin (1921, p. 80) is of particular interest:

The patients lie mute in bed, give no answer of any sort, at most withdraw themselves timidly from approaches, but often do not defend themselves from pinprick. .... They sit helpless before their food; perhaps, however, they let themselves be spoon-fed without making any difficulty.

Kraepelin commented that recall of the events that took place during stupor was sometimes impaired when the patient recovered. Nowadays, the general view is that, on recovery, patients are able to recall nearly all of the events that took place during the period of stupor. It is possible that in some of Kraepelin’s cases there was clouding of consciousness (possibly related to inadequate fluid intake, which is common in these patients). Patients in states of depressive stupor may exhibit catatonic motor disturbances (see Chapter 1).

Atypical depression

The term atypical depression is generally applied to disorders of moderate clinical severity. The precise meaning of the term has varied over the years, but currently it is applied to disorders characterized by:

● variably depressed mood with mood reactivity to

positive events

● overeating and oversleeping

● extreme fatigue and heaviness in the limbs (leaden

paralysis)

● pronounced anxiety.

Many patients with these clinical symptoms have a lifelong tendency to react in an exaggerated way to perceived or real rejection (rejection sensitivity), although this character trait can be exacerbated by the presence of a depressive disorder. Patients with atypical depression also have an earlier onset of illness and a more chronic course. The importance of recognizing atypical depression is that, because of their interpersonal sensitivity, patients with this disorder can be hard to manage and may be regarded as having ‘difficult’ personalities rather than depressive disorder. Traditionally, atypical depression was associated with a poor response to tricyclic antidepressant treatment but had a better outcome with monoamine oxidase inhibitors (MAOIs). However, there is little evidence that the diagnosis of atypical depression predicts response to modern antidepressant drug treatment (see Arnow et al., 2015).

Mixed depression

Mixed affective states have long been recognized in bipolar patients (see Chapter 10), where depressive symptoms are not infrequently detected in patients in whom the main presentation is mania. However, it is possible for patients with major depression to exhibit symptoms that might be seen in mania but do not reach the threshold for diagnosis of bipolar disorder. DSM-5 has a specifier for major depressive episode ‘with mixed features’. The most common symptoms in mixed depression are irritable mood, mood lability, distractibility, agitation, and impulsivity (Perugi et al., 2015). Not surprisingly, such symptoms are more common in depressed patients

with a family history of bipolar disorder, and depressed patients with mixed features are more likely themselves to develop bipolar disorder in the future.

Mild depressive states

It might be expected that mild depressive disorders would present with symptoms similar to those of the depressive disorders described above, but with less intensity. To some extent this is the case, but in mild depressive disorders there are frequently additional symptoms that are less prominent in severe disorders. These symptoms have been characterized in the past as ‘neurotic’, and they include anxiety, phobias, obsessional symptoms, and, less often, dissociative symptoms. In terms of classification, both DSM-5 and ICD-10 have categories of mild depression where criteria for a depressive episode are met but the depressive symptoms are fewer and less severe (see Box 9.1).

Apart from the ‘neurotic’ symptoms that are found in some cases, mild depressive disorders are characterized by the expected symptoms of low mood, lack of energy and interest, and irritability. There is sleep disturbance, but not the early-morning waking that is so characteristic of more severe depressive disorders. Instead, there is more often difficulty in falling asleep, and periods of waking during the night, usually followed by a period of sleep at the end of the night. ‘Biological’ features (poor appetite, weight loss, and low libido) are not usually found. Although mood may vary during the day, it is usually worse in the evening than in the morning. The patient may not appear obviously dejected, or slowed in their movement. Delusions and hallucinations are not present.

In their mildest forms, these cases merge into the minor mood disorders considered below. As described later, they pose considerable problems of classification. Many of these mild depressive disorders are brief, starting at a time of personal misfortune and subsiding when fortunes have changed or a new level of adjustment has been achieved. However, some cases persist for months or years, causing considerable suffering, even though the symptoms do not increase. These chronic depressive states have been termed dysthymia, which is characterized in ICD-10 as the persistence over a number of years of depressive symptoms that are not severe enough to meet criteria for a depressive episode. However, it is not uncommon in such patients for periods of more severe depression to supervene, in which case the diagnosis of depressive episode is made. DSM-5 has a similar category, called ‘Persistent Depressive Disorder (Dysthymia)’, which requires fewer symptoms than those needed to diagnose ‘Major Depressive Disorder’ but stipulates that the symptoms must have persisted for at least 2 years. In DSM-5, this category also includes patients who meet full criteria for ‘Major Depression’ that has persisted for more than 2 years.

Minor anxiety–depressive disorders

We have already seen that anxiety and depressive symptoms often occur together. Indeed, earlier writers considered that anxiety and depressive disorders could not be separated clearly even in patients who had been admitted to hospital with severe disorders. Although most psychiatrists now accept that the distinction can usually be made among the more severe forms that present in psychiatric practice, the distinction is less easy to make in the milder forms that present in primary care.

Classification

As psychiatrists have worked increasingly with general practitioners, the importance of minor anxiety– depressive disorders has been recognized, but without any agreement about classification.

ICD-10 includes a category of ‘mixed anxiety and depressive disorder’, which can be applied when neither anxiety symptoms nor depressive symptoms are severe enough to meet the criteria for an anxiety disorder or a depressive disorder, and when the symptoms do not have the close association with stressful events or significant life changes that is required for a diagnosis of acute stress reaction or adjustment disorder.

According to ICD-10, patients with this presentation are seen frequently in primary care, and there are many others in the general population who are not seen by doctors. In ICD-10 this diagnosis appears among the anxiety disorders, although some psychiatrists consider that the condition is more closely related to the mood disorders, a view that is reflected in the alternative term, minor affective disorder.

In DSM-5, no comparable diagnosis appears in the classification, although there is a category, ‘Unspecified Depressive Disorder’, for depressive symptoms that

cause distress or impairment in social and occupational functioning without meeting criteria for any specific depressive disorder. Although little is known about these conditions or about their relationship to other disorders, patients commonly present to primary care doctors with this group of symptoms. A suitable category is needed even if it is not possible to write strict criteria for diagnosis.

Clinical picture

One of the best descriptions of minor anxiety–depressive disorder is that given by Goldberg et al. (1976), who studied 88 patients from a general practice in Philadelphia. The most frequent symptoms were:

● fatigue

● anxiety

● depression

● irritability

● poor concentration

● insomnia

● somatic symptoms and bodily preoccupation.

A similar range of symptoms was found in the Adult Psychiatric Morbidity in England survey (McManus et al., 2009), which surveyed the frequency of ‘neurotic’ symptomatology in a community sample.

Patients with minor anxiety–depressive disorders commonly present to medical practitioners with prominent somatic symptoms. The reason for this is uncertain; some symptoms are autonomic features of anxiety, and it is possible that patients expect somatic complaints to be viewed more sympathetically than emotional problems. Another point of clinical relevance is that minor affective disorders can be prolonged and in some cases may cause quite disabling difficulties in personal and occupational function. Thus the term ‘minor’ may not capture the serious consequences of the disorder for an individual. In some patients minor affective disorders may represent a residual form of a major mood disturbance (Angst, 2009).