The disorder is characterized by repeated episodes of depression as specified in depressive episode (mild, moderate, or severe), without any history of independent episodes of mood elevation and overactivity that fulfill the criteria of mania. However, the category should still be used if there is evidence of brief episodes of mild mood elevation and overactivity which fulfill the criteria of hypomania immediately after a depressive episode (sometimes apparently precipitated by treatment of a depression). The age of onset and the severity, duration, and frequency of the episodes of depression are all highly variable. In general, the first episode occurs later than in bipolar disorder, with a mean age of onset in the fifth decade. Individual episodes also last between 3 and 12 months (median duration about 6 months) but recur less frequently. Recovery is usually complete between episodes, but a minority of patients may develop a persistent depression, mainly in old age (for which this category should still be used). Individual episodes of any severity are often precipitated by stressful life events; in many cultures, both individual episodes and persistent depression are twice as common in women as in men.
The risk that a patient with recurrent depressive disorder will have an episode of mania never disappears completely, however many depressive episodes he or she has experienced. If a manic episode does occur, the diagnosis should change to bipolar affective disorder.
Recurrent depressive episode may be subdivided, as below, by specifying first the type of the current episode and then (if sufficient information is available) the type that predominates in all the episodes.
* recurrent episodes of depressive reaction, psychogenic depression, reactive depression, seasonal affective disorder
* recurrent episodes of endogenous depression, major depression, manic depressive psychosis (depressed type), psychogenic or reactive depressive psychosis, psychotic depression, vital depression
* recurrent brief depressive episodes
In typical depressive episodes of all three varieties described below (mild, moderate, and severe), the individual usually suffers from depressed mood, loss of interest and enjoyment, and reduced energy leading to increased fatiguability and diminished activity. Marked tiredness after only slight effort is common. Other common symptoms are:
(a) reduced concentration and attention;
(b) reduced self-esteem and self-confidence;
(c) ideas of guilt and unworthiness (even in a mild type of episode);
(d) bleak and pessimistic views of the future;
(e) ideas or acts of self-harm or suicide;
(f) disturbed sleep;
(g) diminished appetite.
The lowered mood varies little from day to day, and is often unresponsive to circumstances, yet may show a characteristic diurnal variation as the day goes on. As with manic episodes, the clinical presentation shows marked individual variations, and atypical presentations are particularly common in adolescence. In some cases, anxiety, distress, and motor agitation may be more prominent at times than the depression, and the mood change may also be masked by added features such as irritability, excessive consumption of alcohol, histrionic behaviour, and exacerbation of pre-existing phobic or obsessional symptoms, or by hypochondriacal preoccupations. For depressive episodes of all three grades of severity, a duration of at least 2 weeks is usually required for diagnosis, but shorter periods may be reasonable if symptoms are unusually severe and of rapid onset.
Some of the above symptoms may be marked and develop characteristic features that are widely regarded as having special clinical significance. The most typical examples of these “somatic” symptoms are: loss of interest or pleasure in activities that are normally enjoyable; lack of emotional reactivity to normally pleasurable surroundings and events; waking in the morning 2 hours or more before the usual time; depression worse in the morning; objective evidence of definite psychomotor retardation or agitation (remarked on or reported by other people); marked loss of appetite; weight loss (often defined as 5% or more of body weight in the past month); marked loss of libido. Usually, this somatic syndrome is not regarded as present unless about four of these symptoms are definitely present.
The categories of mild, moderate and severe depressive episodes described in more detail below should be used only for a single (first) depressive episode. Further depressive episodes should be classified under one of the subdivisions of recurrent depressive disorder.
These grades of severity are specified to cover a wide range of clinical states that are encountered in different types of psychiatric practice. Individuals with mild depressive episodes are common in primary care and general medical settings, whereas psychiatric inpatient units deal largely with patients suffering from the severe grades.
Acts of self-harm associated with mood (affective) disorders, most commonly self-poisoning by prescribed medication, should be recorded by means of an additional code from Chapter XX of ICD-10 (X60-X84). These codes do not involve differentiation between attempted suicide and “parasuicide”, since both are included in the general category of self-harm.
Differentiation between mild, moderate, and severe depressive episodes rests upon a complicated clinical judgement that involves the number, type, and severity of symptoms present. The extent of ordinary social and work activities is often a useful general guide to the likely degree of severity of the episode, but individual, social, and cultural influences that disrupt a smooth relationship between severity of symptoms and social performance are sufficiently common and powerful to make it unwise to include social performance amongst the essential criteria of severity.
The presence of dementia or mental retardation does not rule out the diagnosis of a treatable depressive episode, but communication difficulties are likely to make it necessary to rely more than usual for the diagnosis upon objectively observed somatic symptoms, such as psychomotor retardation, loss of appetite and weight, and sleep disturbance.
* single episodes of depression (without psychotic symptoms), psychogenic depression or reactive depression)
Depressed mood, loss of interest and enjoyment, and increased fatiguability are usually regarded as the most typical symptoms of depression, and at least two of these, plus at least two of the other symptoms described above should usually be present for a definite diagnosis. None of the symptoms should be present to an intense degree. Minimum duration of the whole episode is about 2 weeks.
An individual with a mild depressive episode is usually distressed by the symptoms and has some difficulty in continuing with ordinary work and social activities, but will probably not cease to function completely.
A fifth character may be used to specify the presence of the somatic syndrome:
F32.00 Without somatic symptoms
The criteria for mild depressive episode are fulfilled, and there are few or none of the somatic symptoms present.
F32.01 With somatic symptoms
The criteria for mild depressive episode are fulfilled, and four or more of the somatic symptoms are also present. (If only two or three somatic symptoms are present but they are unusually severe, use of this category may be justified.)
At least two of the three most typical symptoms noted for mild depressive episode should be present, plus at least three (and preferably four) of the other symptoms. Several symptoms are likely to be present to a marked degree, but this is not essential if a particularly wide variety of symptoms is present overall. Minimum duration of the whole episode is about 2 weeks.
An individual with a moderately severe depressive episode will usually have considerable difficulty in continuing with social, work or domestic activities.
A fifth character may be used to specify the occurrence of somatic symptoms:
F32.10 Without somatic symptoms
The criteria for moderate depressive episode are fulfilled, and few if any of the somatic symptoms are present.
F32.11 With somatic symptoms
The criteria for moderate depressive episode are fulfilled, and four or more or the somatic symptoms are present. (If only two or three somatic symptoms are present but they are unusually severe, use of this category may be justified.)
In a severe depressive episode, the sufferer usually shows considerable distress or agitation, unless retardation is a marked feature. Loss of self-esteem or feelings of uselessness or guilt are likely to be prominent, and suicide is a distinct danger in particularly severe cases. It is presumed here that the somatic syndrome will almost always be present in a severe depressive episode.
All three of the typical symptoms noted for mild and moderate depressive episodes should be present, plus at least four other symptoms, some of which should be of severe intensity. However, if important symptoms such as agitation or retardation are marked, the patient may be unwilling or unable to describe many symptoms in detail. An overall grading of severe episode may still be justified in such instances. The depressive episode should usually last at least 2 weeks, but if the symptoms are particularly severe and of very rapid onset, it may be justified to make this diagnosis after less than 2 weeks.
During a severe depressive episode it is very unlikely that the sufferer will be able to continue with social, work, or domestic activities, except to a very limited extent.
This category should be used only for single episodes of severe depression without psychotic symptoms; for further episodes, a subcategory of recurrent depressive disorder should be used.
A severe depressive episode which meets the criteria given for severe depressive episode without psychotic symptoms and in which delusions, hallucinations, or depressive stupor are present. The delusions usually involve ideas of sin, poverty, or imminent disasters, responsibility for which may be assumed by the patient. Auditory or olfactory hallucinations are usually of defamatory or accusatory voices or of rotting filth or decomposing flesh. Severe psychomotor retardation may progress to stupor. If required, delusions or hallucinations may be specified as mood-congruent or mood-incongruent.
Depressive stupor must be differentiated from catatonic schizophrenia, from dissociative stupor, and from organic forms of stupor. This category should be used only for single episodes of severe depression with psychotic symptoms; for further episodes a subcategory of recurrent depressive disorder should be used.
* single episodes of major depression with psychotic symptoms, psychotic depression, psychogenic depressive psychosis, reactive depressive psychosis
© 1992 World Health Organization.