It could be argued that distinguishing schizophrenia from schizoaffective disorder, schizophreniform disorder, delusional disorder, etc. is a largely academic exercise. Until recently, treatment in psychiatry was entirely symptom or syndrome based. Thus manic symptoms respond to antimanic agents including lithium, psychotic symptoms respond to neuroleptics, and depressive symptoms respond to antidepressants.(1. ,.!8) Other 'mood-stabilizing' agents are also of value especially when combined with neuroleptics. However, it is possible that with increasing clinical experience and research using the new generation of 'atypical' antipsychotic agents such as clozapine, risperidone, and olanzapine, more specific indications will emerge. A recent report of efficacy of olanzapine in schizoaffective disorder in comparison to haloperidol is a case in point. (19> However, a tendency to reduce all psychotic disorders to 'serious mental illness' is unfortunate. It encourages a sloppy approach to history taking and the mental state examination, and a loose attitude to making a diagnosis and, if pursued, would prevent the discovery of specific treatments.
The prognostic significance of a diagnosis of schizophrenia (versus schizoaffective and affective disorders) has been discussed in Chapter4.:.3.6 and Chapter4.3.8. Although predicting outcome in individual patients is notoriously difficult (20> because of the influence of idiosyncratic factors such as services, relationships within the family, compliance, intelligence, personality, demographics, etc., the more a disorder approaches 'typical' schizophrenia, the poorer the prognosis tends to be. ^.l.)
That said, schizoaffective disorder is the closest disorder, phenomenologically, to schizophrenia but combines schizophrenic symptoms with affective symptoms. The criteria are discussed in Chapterii4.3..i8.. Schizophreniform (DSM-IV) or acute schizophrenia-like disorders (ICD-10) differ only in terms of duration, as operationally defined (see Chapter 3.3.9). Delusional disorders (Chapter 4..4) differ from schizophrenia in being based around 'non-bizarre' delusions and few or no hallucinations. The onset and course are characteristically later and more benign respectively.
Typical presentations of either mania or depression usually cause few diagnostic difficulties. Overdiagnosis of schizoaffective disorder is to be resisted although the distinction from schizophrenia proper remains controversial and debatable. The guidelines given in DSM-IV attempt to exclude transient mood disturbances (< 2 weeks) in people with psychosis as a basis for a schizoaffective diagnosis.
In practice reaching a diagnosis of schizophrenia in a person with evidence of one or more core symptoms of psychosis (listed under the DSM-IV and ICD-10) may be complicated for the following reasons.
The presence of mood-incongruent delusions (or hallucinations)
'Congruence' is somewhat in the eye of the beholder, especially where mood may be labile or where disturbed mood is suspected but fails to follow clinical stereotypes. The clinician should try to determine if a 'grandiose' delusion is being enjoyed by the patient, and whether the content (e.g. elevated status, magical powers, material riches) is seen as justified by the patient. Similarly a delusion of depressive content (e.g. physical illness, imminent death) must be seen as undeserved or inexplicable to be deemed 'incongruent'. Auditory hallucinations may be comforting, complimentary, or, more commonly, hostile and critical. It is probably their complexity and personification which makes them 'schizophrenic' rather than their mood-incongruent content. (22*
A good history may simply not be available. Symptoms may wax and wane. Partial or successful treatment may modify or curtail a potentially long episode, and onset may be complicated by the use of psychoactive drugs.
This is critical to the diagnosis of schizophrenia, especially the DSM-IV criteria. Here the difficulty is in distinguishing 'premorbid deficits', an illness prodrome and the illness itself. Premorbid personality factors will obscure or set in relief discontinuities in an individual's social trajectory. Objective information and informant testimony is crucial as in most of the diagnostic process. Other individual differences such as intelligence will also shape the presentation of schizophrenia. At the extreme, people with mental retardation (learning disability) may manifest psychosis in less obvious ways (see ChapterJ0.5..1, Cñ§píe.L10.:..5.2 and Chapteri10.5.3). The old diagnosis of 'simple schizophrenia', retained in the ICD-10 describes 'insidious and progressive development of oddities of conduct' and the 'inability to meet the demands of society' that is, social disturbance of long duration. The progressive element distinguishes it from personality disorder although problems adjusting to changing social demands through the lifecycle may give the appearance of progression in a fixed personality disorder.
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