Journal of Affective Disorders, 25 ( 1992) 97- 106 0 1992 Elsevier Science Publishers B.V. All rights resewed 01650327/92/$0.5.00
97
e there any differences between bipolar and unipolar melancholia? Phllip Mitchell, Gordon Parker, Kerry Jamiesen, Kay Wilhelm, Ian Hickie, Henry Brodaty, Philip Boyce, Dusan Hadzi-Pavlovib and Kay Roy School of Psychiatry, University of New South Wales, Sydney, Australiu (Received 5 August 1991) (Revision receive ’ 7 February 1992) (Accc~twi i t tebruary 1992)
Summary
Although it is now more than 30 years since Leonhard originally proposed the distinction between bipolar and monopolar (unipolar) forms of affective disorder, there have been relatively few studies which have investigated clinical features which may differentiate the depressed phase of bipolar disorder from unipolar depression. In this study we examined the value of a new scale for rating depressive mental state signs (the ‘core’ score system), and a large series of symptoms and risk factors, in distinguishmg between 2’7 age and sex-matched pairs of bipo!ar and unipolar patients diagnosed as melancholic on several diagnostic criteria. In general, we found a marked similarity between the groups on clinical features of the depressive episode when allowance was made for multiple tests. Bipolar patients, however, had shorter episodes of depression and were less likely to demonstrate ‘slowed movements’ than unipoiar subjects. There were also consistent trends on other items for psychomotor retardation to be less common and agitation to be more likely in the bipolar patients. At the least, these findings suggest that the widely-held belief that bipolar depressed patients typically &.ave psychomotor retardation is not as clear-cut as has been previously zlescribed.
Key words: l3ipolar disorder; Unipolar disorder; Melancholia;
introduction
Since Leonhard (Y95’7)originally proposed the distinction between bipolar and monopolar (un-
Address for correspondence: Philip Mitchell, Mood Disorders Unit. Prince Henry Hospital, Little Bay, NSW, 2036, Australia. Fax 61-2-661-4329.
Phenomenology;
sychomotor retardation
ipolar) forms of affective disorder-in contrast to Kraepelin’s all-inclusive concept of ‘manic-depressive psychosis’-there have been many atiempts to validate this separation (Angst, 1966; Perris, 1966). Such studies have the potential to delineate differentia: aetiological factors and influense treatment cf these two conditions. There has also been considerable interest in identifying pathophysiological or clinical features which may
differentiate unipolar depression from the depressed phase of bipolar disorder. Any such demonstration of distinguishing features would be of considerable clinical value, particularly for first-onspt depressive episodes or when no accurate past history is available. Whilst a number of biochemical and endocrine investigations has
TABLE
been undertaken, with some suggesting possible biological differences between these syndromes (e.g., Roy et al., 19SS), there have been relatively few studies of comparative clinical features or psychosocial risk factors. In relation to clinical features, Leonhard (1957) emphasised both variability between episodes and
1
Studies of the phenomenology
of bipolar (BP) and unipolar (UP) depression Finding
Variable
Study
I. Duration of episode
Abrams and Taylor,
1980
UP>BP
Coryell et al, 1989
UP>BP
Severity of depression
Katz et al.. 1982
UP>BP
‘Unvarying
Brockingtnn et al.. 1982
UP>BP
Suicidal
Brochington et al., 1982
UP>BP
Initial insomnia
Brockington
UP>BP
Weight loss
Abrams and Taylor.
Muddled
Brockmgton
2. Synptomatolo~ depression’
thoughts
Somatic complamts
et al., 1982 1980
et al., 1982
Beige1 and Murphy,
1971
Katz et al.. 1982 Abrams and Taylor,
UP>BP UP;BP UP>BP UP>BP
1974
n.s.
Dunner et al.. 1976
n.s.
Brockingtor
et al., 1982
BP>UP
Brockington et al.. 1982
BP>UP
Lability of mood
Brockington et al.. 1982
Mania score
Abrams and Taylor,
BP>UP B’ ‘, LIP
Derealisation
Brockington et al.. 1982
PP>UP
Psychotic Features
Guze et al.. 1975
BP>UP
(‘something wrong with body’) Depression worse in morning
1980
Endicott et al, 1985 Beige1 and Murphy, Black and Nasrallah.
BP>UP 1971
n.s.
1989
- ideas of reference
Brockington
-
auditory hallucinations
Brockington et al., 1981
UP>BP
-
loss of insight
Brockington et al., 1981
UP>BP
et al., 1981
:;>BP
3. Mental state signs Activity
Beige1 and Murphy,
19il
Kupfer et al., 1974 -
agitation
Katz et al., 1982
(observed anxiety) -
retardation
(‘haughty attitude’)
a Correlation
wi!h bipolar
disorder.
BP
UP>
BP
Abrams and Taylor,
1980 *
BP>UP
Abrams and Taylor.
1974
n.s.
Brockington et al.. 1982
UP>BP
Dunner et al., 1976
BP>UP
Perris, 1966
ns.
Katz et al.. 1982 Anger/Aggression
UP> UP>BP
n.s.
Beige1 and Murphy,
1971
UP>BP
Abrams and Taylor.
1980 *
BP>UP
Brockington et al., 1982
BP>UP
Dunner et al., 1976
n.s.
99
the ‘polymorphic’ nature of both the depressed and manic phases of bipolar disorder. He used this term ‘polymorphic’ to describe his observation of ‘signs of lability toward the other pole’. He stated that ‘the opposite phase will merely hint at itself not infrequently though it cannot fail to be recognized’. Lconhard also believed that ‘partial states’ (i.e. those with the absence of essential single symptoms, for example, ‘unproductive mania’) were characteristic of both phases of the bipolar form, in comparison to ‘pure’ unipolar melancholia or to unipolar mania. The original vahdation study of Eeonhard’s ClasGfication by Perris (1966) did not demonstrate differentiation between the clinical features of unipolar depression and the depressed phase of bipolar disorder, though the phenomenological component of that work was not extensive. A small number of subsequent investigations (see Table 1) (Beige1 and Murphy, 1971; Abrams and Taylor, 1974, 1980; Kupfer et al., 1974; Dunner et al., 1976; Brockington et al., 1982; and Katz et al., 1982) suggested differences in clinical features, but findings have been inconsistent. Despite these inconsistencies, a picture emerges of unipolar depression being characterised by longer duration of episodes and greater severity; unvarying quality; suicidal inlent; initial insomnia; weight loss; ‘muddled thoughts’; and somatic complaints. On the other hand, bipolar depression has been held to be associated with more severe diurnal mood variation; morning worsening; lability of mood; and derealisation. Most, but not all, investigations have reported higher psychomotor activity levels in unipolar patients. Findings have also been discrepant for psychotic features, anger and aggression. It should be noted, however, that due to a large number of comparisons being made between these two groups, most investigations have only reported the significant differences (e.g. Brockington et al., 1982), but few have acknowledged that even these relatively few positive results mav in fact have been chance or type I errors. We have recently suggested that a sub-set of mental state signs of depression (so-called ‘core’ signs) may be superior to symptoms in discriminating between melancholic and other depres-
sives (Parker et al., 1990). As an e*ension, we sought to examine the value of these signs in distinguishing between bipolar and unipolar melancholic depressed patients. As part of a comprehensive assessment, we also examined the relevance of depressive symptoms and a number of possible antecedent psychosocial risk factors. Methods The patients selected for this study were derived from 305 consecutively diagnosed primary depressive subjects assessed as inpatients or outpatients of a specialised Mood Disorders Unit. During a ‘semi-structured’ interview (Brodaty et al., 1987), diagnostic data were obtained by an interviewing (research and treating) psychiatrist. We rated an extensive list of current mental state signs and symptoms experienced at the nadir of the present episode as previously described (Parker et al., 1990). ‘Clinical episode diagnoses’ corresponding broadly to ICD-9 categories were made from data obtained at the semi-structured interview, and reviewed during treatment and at follow-up, while DSM-III and RDC diagnoses were made from features elicited at baseline. In order to avoid spurious comparisons between bipolar depressed patients and a heterogeneous unipolar group largely comprised of nonmelancholic subjects, we only inciude bipolar and unipolar depressed patients who met each of the DSM-III, RDC and ‘core’ (Parker et al., 1990) criteria for melancholia (or endogenous depression) in this study. These diagnostic criteria resulted in 138 of the 305 patients being assigned as ‘composite melancholies’. In excluding 19% of those rated as melancholic by the DSM-III system alone, 44% of those rated as endogenously depressed by the RDC system alone, and 22% who scored above the melancholia cut-off score for the ‘core’ system, the multi-system ‘composite’ criteria imposed a rigourous definition of melancholia. Bipolar melancholic patients were then defined as those fulfilling RDC criteria for past manic or hypomanic episodes. The clinical data necessary to determine these diagnoses were obtained from both the initial assessment interview and previous medical records. As these diagnoses
100
were by definition retrospective, assignment to the ‘bipolar’ category was made only if supportive features were recorded as being unequivocally present. Of the initial 138 ‘composite melancholics’, 27 were rated as bipolar (17 manic, lG hypomanic). These 27 patients were then matched for age and sex with 27 of the remaining 111 unipolar ‘composite meLncholics’. Matching was undertaken by pairing each bipolar patient with a unipolar patient of Lhe same sex and of the closest age. This resulted in age matching within one year for all patients. At interview, all depressed patients had been asked to nominate stressful life events occurring or persisting in the 12 months preceding the onset of the depression, together with details on early development and family history of psychotic disorders. In addition, to assess current depression severity, they were asked to complete the self-report Zung Depression Rating Scale (Zung, 1965), while the psychiatrist completed the Hamilton Rating Scale for Depression (Hamilton, 1960). Comparisons between bipolar and unipolar depressives were undertaken using the two-tailed Student’s t-test for dimensional data (paired ttests were used for the comparison of matched subjects) and the chi sauare test for categorical data (McNemar test for matched pairs). We compared the 27 bipolar melancholic patients with
TABLE
3
Comparison
of mental state signs (McNemar Bipolar %
Sign
1. Lack of personal care
33.3
22.2
2. Unto-operative
48.1
22.2 +
attitude
3. Depressed affect initially 4. Non-responsive
to interviewer
100.0
92.6
63.0
59.3
5. Dull/inattentive
44.4
37.0
6. Depressed affect maintained
88.9
88.9
100.0
96.3
8. Persistently miserable
92.6
85.2
9. Immobile
81.5
88.‘)
7. Persistently worried face
IO. Querulous
40.7
and irritable
18.5
70.4
66.7
12. Self pre-occupation
70.4
70.4
13. Not able to be cheered up
92.6
88.9
14. Slumped posture
55.6
66.7
15. Immobility
44.4
70.4
16. Slowed movements
37.0
66.7 *
17. Slowed speech
48.1
55.6
18. Inaudible
25.9
33.3
19. Mute or reduced speech
37.0
59.3
20. Loss of spontaneous talk
59.3
66.7
Il. Facial agitation
21. Speech favouring self
66.7
74.1
22. Reduced themes
63.0
55.6
23. Poverty of associations
70.4
70.4
24. Retardation
63.0
74.1
of movement
25. Agitated
movements
63.0
37.0
26. Impaired
concentration
88.9
70.4
27. Impaired
insight
51.9
25.9
28. Excessive guilt
81.5
70.4
20. Nihilistic
63.0
29.6 *
XI.5
81.5
96.3
74.1 +
30. Observable
* P
97
e there any differences between bipolar and unipolar melancholia? Phllip Mitchell, Gordon Parker, Kerry Jamiesen, Kay Wilhelm, Ian Hickie, Henry Brodaty, Philip Boyce, Dusan Hadzi-Pavlovib and Kay Roy School of Psychiatry, University of New South Wales, Sydney, Australiu (Received 5 August 1991) (Revision receive ’ 7 February 1992) (Accc~twi i t tebruary 1992)
Summary
Although it is now more than 30 years since Leonhard originally proposed the distinction between bipolar and monopolar (unipolar) forms of affective disorder, there have been relatively few studies which have investigated clinical features which may differentiate the depressed phase of bipolar disorder from unipolar depression. In this study we examined the value of a new scale for rating depressive mental state signs (the ‘core’ score system), and a large series of symptoms and risk factors, in distinguishmg between 2’7 age and sex-matched pairs of bipo!ar and unipolar patients diagnosed as melancholic on several diagnostic criteria. In general, we found a marked similarity between the groups on clinical features of the depressive episode when allowance was made for multiple tests. Bipolar patients, however, had shorter episodes of depression and were less likely to demonstrate ‘slowed movements’ than unipoiar subjects. There were also consistent trends on other items for psychomotor retardation to be less common and agitation to be more likely in the bipolar patients. At the least, these findings suggest that the widely-held belief that bipolar depressed patients typically &.ave psychomotor retardation is not as clear-cut as has been previously zlescribed.
Key words: l3ipolar disorder; Unipolar disorder; Melancholia;
introduction
Since Leonhard (Y95’7)originally proposed the distinction between bipolar and monopolar (un-
Address for correspondence: Philip Mitchell, Mood Disorders Unit. Prince Henry Hospital, Little Bay, NSW, 2036, Australia. Fax 61-2-661-4329.
Phenomenology;
sychomotor retardation
ipolar) forms of affective disorder-in contrast to Kraepelin’s all-inclusive concept of ‘manic-depressive psychosis’-there have been many atiempts to validate this separation (Angst, 1966; Perris, 1966). Such studies have the potential to delineate differentia: aetiological factors and influense treatment cf these two conditions. There has also been considerable interest in identifying pathophysiological or clinical features which may
differentiate unipolar depression from the depressed phase of bipolar disorder. Any such demonstration of distinguishing features would be of considerable clinical value, particularly for first-onspt depressive episodes or when no accurate past history is available. Whilst a number of biochemical and endocrine investigations has
TABLE
been undertaken, with some suggesting possible biological differences between these syndromes (e.g., Roy et al., 19SS), there have been relatively few studies of comparative clinical features or psychosocial risk factors. In relation to clinical features, Leonhard (1957) emphasised both variability between episodes and
1
Studies of the phenomenology
of bipolar (BP) and unipolar (UP) depression Finding
Variable
Study
I. Duration of episode
Abrams and Taylor,
1980
UP>BP
Coryell et al, 1989
UP>BP
Severity of depression
Katz et al.. 1982
UP>BP
‘Unvarying
Brockingtnn et al.. 1982
UP>BP
Suicidal
Brochington et al., 1982
UP>BP
Initial insomnia
Brockington
UP>BP
Weight loss
Abrams and Taylor.
Muddled
Brockmgton
2. Synptomatolo~ depression’
thoughts
Somatic complamts
et al., 1982 1980
et al., 1982
Beige1 and Murphy,
1971
Katz et al.. 1982 Abrams and Taylor,
UP>BP UP;BP UP>BP UP>BP
1974
n.s.
Dunner et al.. 1976
n.s.
Brockingtor
et al., 1982
BP>UP
Brockington et al.. 1982
BP>UP
Lability of mood
Brockington et al.. 1982
Mania score
Abrams and Taylor,
BP>UP B’ ‘, LIP
Derealisation
Brockington et al.. 1982
PP>UP
Psychotic Features
Guze et al.. 1975
BP>UP
(‘something wrong with body’) Depression worse in morning
1980
Endicott et al, 1985 Beige1 and Murphy, Black and Nasrallah.
BP>UP 1971
n.s.
1989
- ideas of reference
Brockington
-
auditory hallucinations
Brockington et al., 1981
UP>BP
-
loss of insight
Brockington et al., 1981
UP>BP
et al., 1981
:;>BP
3. Mental state signs Activity
Beige1 and Murphy,
19il
Kupfer et al., 1974 -
agitation
Katz et al., 1982
(observed anxiety) -
retardation
(‘haughty attitude’)
a Correlation
wi!h bipolar
disorder.
BP
UP>
BP
Abrams and Taylor,
1980 *
BP>UP
Abrams and Taylor.
1974
n.s.
Brockington et al.. 1982
UP>BP
Dunner et al., 1976
BP>UP
Perris, 1966
ns.
Katz et al.. 1982 Anger/Aggression
UP> UP>BP
n.s.
Beige1 and Murphy,
1971
UP>BP
Abrams and Taylor.
1980 *
BP>UP
Brockington et al., 1982
BP>UP
Dunner et al., 1976
n.s.
99
the ‘polymorphic’ nature of both the depressed and manic phases of bipolar disorder. He used this term ‘polymorphic’ to describe his observation of ‘signs of lability toward the other pole’. He stated that ‘the opposite phase will merely hint at itself not infrequently though it cannot fail to be recognized’. Lconhard also believed that ‘partial states’ (i.e. those with the absence of essential single symptoms, for example, ‘unproductive mania’) were characteristic of both phases of the bipolar form, in comparison to ‘pure’ unipolar melancholia or to unipolar mania. The original vahdation study of Eeonhard’s ClasGfication by Perris (1966) did not demonstrate differentiation between the clinical features of unipolar depression and the depressed phase of bipolar disorder, though the phenomenological component of that work was not extensive. A small number of subsequent investigations (see Table 1) (Beige1 and Murphy, 1971; Abrams and Taylor, 1974, 1980; Kupfer et al., 1974; Dunner et al., 1976; Brockington et al., 1982; and Katz et al., 1982) suggested differences in clinical features, but findings have been inconsistent. Despite these inconsistencies, a picture emerges of unipolar depression being characterised by longer duration of episodes and greater severity; unvarying quality; suicidal inlent; initial insomnia; weight loss; ‘muddled thoughts’; and somatic complaints. On the other hand, bipolar depression has been held to be associated with more severe diurnal mood variation; morning worsening; lability of mood; and derealisation. Most, but not all, investigations have reported higher psychomotor activity levels in unipolar patients. Findings have also been discrepant for psychotic features, anger and aggression. It should be noted, however, that due to a large number of comparisons being made between these two groups, most investigations have only reported the significant differences (e.g. Brockington et al., 1982), but few have acknowledged that even these relatively few positive results mav in fact have been chance or type I errors. We have recently suggested that a sub-set of mental state signs of depression (so-called ‘core’ signs) may be superior to symptoms in discriminating between melancholic and other depres-
sives (Parker et al., 1990). As an e*ension, we sought to examine the value of these signs in distinguishing between bipolar and unipolar melancholic depressed patients. As part of a comprehensive assessment, we also examined the relevance of depressive symptoms and a number of possible antecedent psychosocial risk factors. Methods The patients selected for this study were derived from 305 consecutively diagnosed primary depressive subjects assessed as inpatients or outpatients of a specialised Mood Disorders Unit. During a ‘semi-structured’ interview (Brodaty et al., 1987), diagnostic data were obtained by an interviewing (research and treating) psychiatrist. We rated an extensive list of current mental state signs and symptoms experienced at the nadir of the present episode as previously described (Parker et al., 1990). ‘Clinical episode diagnoses’ corresponding broadly to ICD-9 categories were made from data obtained at the semi-structured interview, and reviewed during treatment and at follow-up, while DSM-III and RDC diagnoses were made from features elicited at baseline. In order to avoid spurious comparisons between bipolar depressed patients and a heterogeneous unipolar group largely comprised of nonmelancholic subjects, we only inciude bipolar and unipolar depressed patients who met each of the DSM-III, RDC and ‘core’ (Parker et al., 1990) criteria for melancholia (or endogenous depression) in this study. These diagnostic criteria resulted in 138 of the 305 patients being assigned as ‘composite melancholies’. In excluding 19% of those rated as melancholic by the DSM-III system alone, 44% of those rated as endogenously depressed by the RDC system alone, and 22% who scored above the melancholia cut-off score for the ‘core’ system, the multi-system ‘composite’ criteria imposed a rigourous definition of melancholia. Bipolar melancholic patients were then defined as those fulfilling RDC criteria for past manic or hypomanic episodes. The clinical data necessary to determine these diagnoses were obtained from both the initial assessment interview and previous medical records. As these diagnoses
100
were by definition retrospective, assignment to the ‘bipolar’ category was made only if supportive features were recorded as being unequivocally present. Of the initial 138 ‘composite melancholics’, 27 were rated as bipolar (17 manic, lG hypomanic). These 27 patients were then matched for age and sex with 27 of the remaining 111 unipolar ‘composite meLncholics’. Matching was undertaken by pairing each bipolar patient with a unipolar patient of Lhe same sex and of the closest age. This resulted in age matching within one year for all patients. At interview, all depressed patients had been asked to nominate stressful life events occurring or persisting in the 12 months preceding the onset of the depression, together with details on early development and family history of psychotic disorders. In addition, to assess current depression severity, they were asked to complete the self-report Zung Depression Rating Scale (Zung, 1965), while the psychiatrist completed the Hamilton Rating Scale for Depression (Hamilton, 1960). Comparisons between bipolar and unipolar depressives were undertaken using the two-tailed Student’s t-test for dimensional data (paired ttests were used for the comparison of matched subjects) and the chi sauare test for categorical data (McNemar test for matched pairs). We compared the 27 bipolar melancholic patients with
TABLE
3
Comparison
of mental state signs (McNemar Bipolar %
Sign
1. Lack of personal care
33.3
22.2
2. Unto-operative
48.1
22.2 +
attitude
3. Depressed affect initially 4. Non-responsive
to interviewer
100.0
92.6
63.0
59.3
5. Dull/inattentive
44.4
37.0
6. Depressed affect maintained
88.9
88.9
100.0
96.3
8. Persistently miserable
92.6
85.2
9. Immobile
81.5
88.‘)
7. Persistently worried face
IO. Querulous
40.7
and irritable
18.5
70.4
66.7
12. Self pre-occupation
70.4
70.4
13. Not able to be cheered up
92.6
88.9
14. Slumped posture
55.6
66.7
15. Immobility
44.4
70.4
16. Slowed movements
37.0
66.7 *
17. Slowed speech
48.1
55.6
18. Inaudible
25.9
33.3
19. Mute or reduced speech
37.0
59.3
20. Loss of spontaneous talk
59.3
66.7
Il. Facial agitation
21. Speech favouring self
66.7
74.1
22. Reduced themes
63.0
55.6
23. Poverty of associations
70.4
70.4
24. Retardation
63.0
74.1
of movement
25. Agitated
movements
63.0
37.0
26. Impaired
concentration
88.9
70.4
27. Impaired
insight
51.9
25.9
28. Excessive guilt
81.5
70.4
20. Nihilistic
63.0
29.6 *
XI.5
81.5
96.3
74.1 +
30. Observable
* P
