Differential Diagnosis and Therapeutic Management of Schizoaffective Disorder

Article excerpt

Introduction

An estimated 1 of 4 inpatient psychiatry admissions is attributed to schizoaffective disorder (SAD). (1), (2) Lifetime prevalence of this important yet poorly understood disorder ranges between 0.5% and 0.8%. Despite its common presentation, few studies with selectively enriched SAD patient populations have been conducted; therefore, information about the phenomenology and treatment of SAD derives more from observational studies or small, post hoc analyses, than from large-scale randomized studies.

SAD is a heterogeneous clinical construct marked by mixed psychotic and affective symptoms, the inter-relationships of which vary considerably between and within individuals, presenting formidable challenges even to experienced psychiatrists. (3), (4) The bipolar and depressive subtypes of SAD exert different influences on perception, cognition, affect, mood, and physiological functioning. Knowledge about the clinical features, differential diagnosis, clinical course, and management of SAD has been shaped by diversity of opinion more than by consensus within the field, precluding even the most rudimentary definitions for standard of care. In the American nosology, diagnostic inclusion and exclusion criteria were not specified prior to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). International Classification of Diseases and Related Health Problems 10th revision (ICD-10) criteria for SAD differ in several fundamental respects from those of DSM-IV (Table 1, page S4) (3), (5) and likely contribute to variations in diagnostic practice in the United States and abroad. The paucity of established treatments for SAD, particularly with agents approved by the U.S. Food and Drug Administration, may further diminish the ability of clinicians to diagnose and treat SAD with confidence.

TABLE 1 DSM-IV TR and ICD-10 diagnostic criteria for SAD

                          Diagnostic Criteria

        Affective          Schizophrenic         Duration

DSM-IV  Major depressive,  Meeting Criterion A   Major depressive
        manic, or mixed    for schizophrenia     episode 2 weeks;
        episode            (presence of          mixed or manic 1
                           [greater than or      week Psychotic
                           equal to]2            symptoms 1 month to
                           delusions,            meet Criterion A for
                           hallucinations,       schizophrenia
                           disorganized speech,
                           behavioral
                           disturbances, or
                           negative symptoms)

ICD-10  Prominent manic,   One, preferably 2 of  Mania [greater than
        depressive, or     (a)-(d) symptoms for  or equal to] 1 week;
        mixed symptoms     schizophrenia *       depression [greater
                                                 than or equal to]2
                                                 weeks

                        Diagnostic Criteria

        Simultaneity                   Additional

DSM-IV  During the same period of the  Delusions or hallucinations
        illness                        for [greater than or equal to]
                                       2 weeks without prominent mood
                                       symptoms Mood symptoms as a
                                       substantial portion of the
                                       total illness duration

ICD-10  Simultaneous, or at least
        within a few days of each
        other

* Symptoms include (a) thought echo, thought insertion or withdrawal,
or thought broadcasting; (b) delusions of control, influence or
passivity, clearly referred to body or limb movements or specific
thoughts, actions, or sensations; delusional perception; (c)
hallucinatory voices giving a running commentary on the patient's
behavior, or discussing him between themselves, or other types of
hallucinatory voices coming from some part of the body; (d) persistent
delusions of other kinds that are culturally inappropriate and
completely impossible (eg, being able to control the weather, being in
communication with aliens from another world). …