The American Psychiatric Association’s DSM-IV presents the symptoms of mental disorders in the form of grouped criteria. The following are the details of the diagnostic criteria for schizophrenia.
Diagnostic criteria for Schizophrenia
A. Characteristic symptoms: Two (or more) for the following, each present for a significant portion of time during a 1-month period (or less if successfully treated):
Note: Only one Criterion A symptom is required if delusions are bizarre or hallucinations consist of a voice keeping up a running commentary on the person’s behaviour or thoughts, or two or more voices conversing with each other.
B. Social/occupational dysfunction: For a significant portion of the time since the onset of the disturbance, one or more major areas of functioning such as work, interpersonal relations, or self-care are markedly below the level achieved prior to the onset (or when the onset is in childhood or adolescence, failure to achieve expected level of interpersonal, academic, or occupational achievement).
C. Duration: Continuous signs of the disturbance persist for at least 6 months. This 6-month period must include at least 1 month of symptoms (or less if successfully treated) that meet Criterion A (that is, active-phase symptoms) and may include prodromal or residual symptoms. During these prodromal or residual periods, the signs of the disturbance may be manifested by only negative symptoms or two or more symptoms listed in Criterion A present in an attenuated form (for example, odd beliefs, unusual perceptual experiences).
D. Schizoaffective and Mood Disorder exclusion: Schizoaffective Disorder and Mood Disorder With Psychotic Features have been ruled out because either (1) no Major Depressive, Manic, or Mixed Episodes have occurred concurrently with the active-phase symptoms; or (2) if mood episodes have occurred during active-phase symptoms, their total duration has been brief relative to the duration of the active and residual periods.
E. Substance/general medical condition exclusion: The disturbance is not due to the direct physiological effects of a substance (for example, a drug of abuse, a medication) or a general medical condition.
F. Relationship to a Pervasive Developmental Disorder: If there is a history of Autistic Disorder or another Pervasive Developmental Disorder, the additional diagnosis of Schizophrenia is made only if prominent delusions or hallucinations are present for at least a month (or less if successfully treated).[46]
The above symptoms are meant to be guidelines for identifying the presence of schizophrenia in general. Once a diagnostician decides schizophrenia is present, the next task is to determine which of the various subtypes is the most appropriate label. DSM-IV provides a choice from five subtypes: Paranoid Type, in which the person is preoccupied with delusions or auditory hallucinations; Disorganised Type, characterised by disorganised speech or behaviour; Catatonic Type, involving abnormal movements or strange postures; Undifferentiated Type, in which the primary symptoms of schizophrenia are present but do not fit the criteria for Paranoid, Disorganised or Catatonic subtypes; and Residual Type, for a person who has had at least one episode of schizophrenia and in whom residual indications of disturbance remain.
The various classifications of mental disorders relating to psychosis are presented in both DSM-IV and ICD-10 as if it is assumed there is a continuous spectrum of disorder that has to be broken up into recognisable segments. The result is that schizophrenia, as it is described in both manuals, shades into a number of descriptions of similar but supposedly clinically distinct disorders. The problem is that the symptoms don’t always clearly demonstrate these clinical distinctions.
For example, in the DSM-IV system, Delusional Disorder is described as a psychotic condition which is distinguished from Schizophrenia largely by an understanding that the ‘delusions’ of Schizophrenia are usually ‘bizarre’ whereas those of Delusional Disorder are non-bizarre.[47] To facilitate this distinction, DSM-IV defines a ‘bizarre’ delusion as one ‘that involves a phenomenon that the person’s culture would regard as totally implausible.’[48] This leaves diagnosticians to assume that the non-bizarre delusions of Delusional Disorder must be delusions that the person’s culture does find plausible.
Seven subtypes of Delusional Disorder are given in DSM-IV. The Erotomanic Type, for instance, defines unrequited love as a pathological symptom and claims a diagnosis ‘applies when the central theme of the delusion is that another person is in love with the individual. The delusion often concerns idealised romantic love and spiritual union rather than sexual attraction . . . Most individuals with this subtype in clinical samples are female.’[49]
Similarly, a Delusional Disorder of the Jealous Type involves a supposedly non-bizarre sign of pathology which ‘applies when the central theme of the person’s delusion is that his or her spouse or lover is unfaithful’.[50] What! Run that again! How could the diagnosing psychiatrist possibly know with any certainty whether the patient’s suspicion is a delusion or the truth? Is it simply a matter of consulting the suspected spouse? This kind of question is highly relevant when one considers the power vested in psychiatrists to lock up and force treatment on people diagnosed with delusional symptoms.[51]
Without any laboratory tests, a diagnostician can only rely on evidence provided by the speech and behaviour of the person in question, together with reports from third parties. The person’s behaviour first has to be tested, in the diagnostician’s own mind, against the range of normal speech and behaviours that is within the diagnostician’s experience. This will determine whether the person’s mental state deviates too greatly from normal and is therefore pathological. Then, if it is judged to be abnormal, it has to be fitted into the correct point on the spectrum of mental disorders.
In regard to diagnosing schizophrenia this would seem to be a task fraught with possibilities for inconsistency. If, for instance, a person is expressing religious beliefs the diagnostician must first determine whether they are delusional: that is, false beliefs not ‘ordinarily accepted by other members of the person’s culture or subculture’.[52] If they appear to be delusional, the diagnostician then has to decide whether the delusions are bizarre, and therefore indicative of Schizophrenia. If they are non-bizarre the alternative diagnosis might be Delusional Disorder—Grandiose Type: ‘Grandiose delusions may have a religious content (for example the person believes that he or she has a special message from a deity).’[53]
The risk of inconsistency is readily apparent given the distinctly bizarre appearance of many religious beliefs that are culturally acceptable and which are therefore not considered delusional (in the psychiatric sense). Thousands of people may practise a pseudo-cannibalistic ritual together, believing the biscuits and grape juice they consume to symbolise the body and blood of a god. But if the ritual belongs to a respectable mainstream Christian church, and is therefore culturally acceptable, by necessity psychiatrists must view it as being motivated by a non-pathological cause. However, if a solitary individual were to invent and practise a similar ritual it is unlikely the same protection would be available. Such a person might easily be given a diagnosis of schizophrenia and, if so, would probably also be considered dangerous. This means that the level of popularity of certain kinds of thoughts and beliefs, rather than their type or quality, is a deciding factor in some diagnoses of schizophrenia. This is a fairly curious notion of disease, but not unique.
Next: Notions About the Meaning of Disease
[46] American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, pp. 285–6.
[47] Ibid., p. 284.
[48] Ibid., p. 765.
[49] Ibid., p. 297.
[50] Ibid.
[51] ‘Delusions’ is one of five symptoms specified in the NSW Mental Health Act which, if identified by a medical practitioner, can lead to involuntary incarceration and treatment. See New South Wales Parliament, Mental Health Act 1990.
[52] American Psychiatric Association, op. cit., p. 765.
[53] Ibid., p. 297.