Northern Birmingham Mental Health NHS Trust and University of Birmingham, Birmingham
Department of Psychology, Institute of Psychiatry, London
Department of Clinical Psychology, University of Exeter
School of Psychology, University of Birmingham, UK
Correspondence: Max Birchwood, Department of Clinical Psychology, University of Birmingham, Harry Watton House, 97 Church Lane, Aston, Birmingham B6 5UG, UK
Declaration of interest As paper I.
See pp. 516-521, this
issue.
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ABSTRACT |
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Aims We apply our cognitive framework to PPD and chart the appraisal of self and psychosis and their link with the later emergence of PPD.
Method Patients with ICD-10 schizophrenia (n=105) were followed up over 12 months following the acute episode, taking measures of depression, working self-concept, cognitive vulnerability, insight and appraisals of psychosis.
Results Before developing PPD, these patients felt greater loss, humiliation and entrapment by their illness than those who relapsed or did not become depressed, and were more likely to see their future selves in lower status roles. Upon becoming depressed, participants developed greater insight, lower self-esteem and a worsening of their appraisals of psychosis.
Conclusions Depression in psychosis arises from the individual's appraisal of psychosis and its implications for his/her perceived social identity, position and group fit. Patients developing PPD feel forced to accept a subordinate role without opportunity for escape. Implications for treatment are discussed.
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INTRODUCTION |
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METHOD |
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Hypotheses
Measures
Appraisal of psychosis
Participants' cognitive appraisal of their illness was evaluated using the
Personal Beliefs about Illness Questionnaire (PBIQ;
Birchwood et al,
1993). The PBIQ is comprised of 16 items rated on a four-point
scale and assesses patients' beliefs in five domains: loss, humiliation,
shame, attribution of behaviour to self or to illness and entrapment in
psychosis. The scale has been shown to have a good level of reliability and
validity with schizophrenia.
The Insight Scale (Birchwood et al, 1994) is a rapid self-report measure, specifically developed for psychotic populations, consisting of eight statements to which the subject responds in one of three ways: agree, disagree and unsure. The scale provides three insight factors (relabelling of symptoms, awareness of illness and need for treatment) in addition to a total insight score. The scale has been shown to have excellent reliability and both concurrent and criterion validity.
Depression (cognitive) vulnerability
Depression vulnerability was assessed using the Depressive Experiences
Questionnaire (DEQ; Blatt et al,
1976) and the Crown Self-Esteem Scale
(Crown et al, 1977).
The DEQ is a self-report measure consisting of 66 items rated for conviction
of belief for each item on a seven-point scale: from strongly
disagree to strongly agree. The reliability of the DEQ is
well established with both adult and adolescent depressive populations and
three highly stable factors can be calculated: sociotropy, self-criticism and
self-efficacy (Blatt et al,
1976).
The Crown scale is a variant of Rosenberg's original self-esteem measure (Rosenberg, 1965) and consists of ten items. It is a self-report inventory that provides a rapid evaluation of patient's self-esteem. Each item is rated on a four-point scale: from strongly agree to strongly disagree. Item directionality and scoring is such that a lower score depicts higher levels of self-esteem. Extensive use of the scale by both Rosenberg (1965) and Crown et al (1977) suggests good levels of reliability across a range of populations (see Table 1).
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The working self-concept
The short (80-item) form of the Possible Selves Questionnaire (PosSq;
Marcus & Nurius, 1986) is
a self-rated measure of self-knowledge that provides representations of the
self in the past, present and future. The 80 items are personality descriptors
with an equal number of items covering five areas: general abilities,
lifestyle possibilities, general descriptions, physical characteristics and
possibilities tied to the opinion of others. Half of the items are high-status
or positive selves and the other half are low-status or
negative selves.
The development of the low- and high-status items for the PosSQ involved asking a community sample to "tell us what is possible for you" and generated 150 distinct possibilities for the self, utilised in the long version of the questionnaire, which also included a sixth domain of personality descriptors: possibilities reflecting various occupational alternatives (Marcus & Nurius, 1986). An equal number of items judged as positive, negative and neutral were employed within each of these six categories. The short form of the PosSQ used here omits all neutral items and also the category of occupational possible selves.
Each descriptor or possible self is rated on a five-point scale from not at all to very much on four questions:
The short form of the PosSQ provides three weighted variables for both the high-status and low-status self-representations: the now self, the probable self and the like-to-be self. Prior to calculating the variables, each item's importance to self rating (i.e. from question (d)) was employed as a cutoff, so that only descriptors rated as somewhat, quite a bit or very much important are included in calculating the possible selves variables. This procedure accounted for the individual differences between participants' self-representations (i.e. certain possible selves will be more important to some participants than others and therefore, the ratings for now, probable and ideal selves would be affected by this subjectivity). A mean score for high- and low-status now, probable and ideal selves was then obtained.
The PosSQ is a valid and reliable measure of self-knowledge and, in addition, is highly correlated with self-esteem measures (Marcus & Nurius, 1986).
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RESULTS |
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Comparison of PPD with non-PPD groups
Beliefs about psychosis
Figure 1 shows the course of
the five beliefs about psychosis measured in the PBIQ in the PPD and non-PPD
groups. The factors measure patients' beliefs about their psychosis and its
implications for the self as described in Rooke & Birchwood
(1998): entrapment
(control over illness); shame; loss of autonomy and valued
social role; humiliation and loss of rank, arising from a belief in
the social segregation of those with mental illness; and attribution
(self v. illness as responsible for behaviour/experience).
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The first hypothesis was tested using a MANOVA model with factors of group (PPD v. non-PPD), time (pre-PPD and PPD) and their interaction. The dependent variables were entrapment, shame, social humiliation, loss and attribution of illness to the self. A significant group effect (F=3.4, d.f.=5, 53, P <0.01) and group x time interaction (F=2.5, d.f.=5, 53, P <0.05) emerged.
The main test of the hypothesis is the difference between groups at the pre-PPD stage. At this stage (i.e. when neither group was depressed), the PPD group was significantly more likely than non-PPD participants to attribute the cause of psychosis to the self rather than an externalised illness (F=4.3, P <0.05), to perceive greater loss of autonomy and valued role (F=4.9, P <0.05) and to perceive themselves to be humiliated (F=4.0, P=0.05) and entrapped by their illness (F=3.5, P=0.07). No difference was observed between the two groups for shame (F<1, NS).
At the PPD stage (i.e. while depressed) all five PBIQ appraisals were significantly more negative in those participants with PPD (entrapment: F=27.5, P <0.001; shame: F=10.3, P <0.01; social humiliation: F=8.0, P <0.01; illness attributed to self: F=9.4, P <0.01, loss of autonomy/ role: F=12.8, P <0.01).
Ideal versus probable self
Table 2 depicts the mean
scores for ratings of now, probable and
like-to-be (ideal) possible selves in both low-status and
high-status domains for the PPD and non-PPD groups. In line with the
hypothesis, participants developing PPD were more likely to evaluate their
future (i.e. probable) roles as low status than
those who did not become depressed (t=2.7, P <0.01). This
held even when controlling for depression at the time of testing. As
anticipated, no difference was evident for low-status roles for
now and like-to-be selves (t<2, NS).
However, for the high-status roles, no difference was observed between the two
groups for now, probable and
like-to-be selves (t<1, NS).
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In other words, both PPD and non-PPD patients' evaluation of their aspired-to (and current) roles were identical; however, patients developing PPD anticipated lower status future roles, whereas those not developing PPD were less likely to see their future as being of a lower status. The converse does not apply: PPD patients did not invest less in higher status roles.
Depression vulnerability
Self-esteem. Figure
2 depicts the course of mean self-esteem for both PPD and non-PPD
groups (increasing score depicting greater negativity of esteem). To test the
first hypothesis, a similar MANOVA model, with factors of group and time as
outlined above, was employed and revealed a significant time effect
(F=7.9, d.f.=1, 54, P <0.01) and group x time
interaction (F=16.5, d.f.=1, 57, P <0.01).
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Scores for PPD and non-PPD groups were compared at both pre-PPD (not depressed) and PPD observation points: participants developing PPD were more likely to have significantly lower self-esteem at both observation points, including the point at which neither group was depressed (i.e. pre-PPD; P <0.01).
Sociotropy, self-efficacy and self-criticism. The PPD group participants were significantly more self-critical than those who remained non-depressed, implying that the depressed group had lower self-esteem (F=14.2, P <0.001). In addition, the DEQ vulnerability factor of sociotropy approached significance (F=3.6, P=0.06) with higher scores in the PPD group. Self-efficacy was not a significant discriminator between the PPD and non-PPD groups.
Insight. The course of insight, specifically the awareness of illness, the relabelling of symptoms and the need for treatment, is depicted as a total insight score for both PPD and non-PPD groups in Fig. 3. The MANOVA model revealed a significant group effect (F=7.0, d.f.=3, 54, P <0.01) and group x time interaction (F=3.0, d.f.=3, 54, P <0.05). The main test of the first hypothesis is the difference between groups at the pre-PPD stage, where no difference was apparent between the PPD and non-PPD groups on any insight variables: awareness (F=2.8, NS); symptom relabelling (F=2.6, NS); treatment need (F=0.5, NS) and total insight (F=0.9, NS).
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When patients were depressed, however, the reported greater insight, including awareness of illness (F=16.2, P <0.001), relabelling of symptoms (F=7.3, P <0.01), need for treatment (F=4.2, P <0.05) and total insight score (F=10.1, P <0.01).
Experience of psychosis
The PPD group did not experience most relapse, use of the Mental Health Act
or longer duration of illness. Indeed, patients with a first episode of
psychosis were more prone to PPD than those with multiple episodes (50%
v. 32%; P <0.01). Patients with PPD were no more likely
to be unemployed than the non-PPD group.
Comparing relapsing with non-relapsing patients
In the following analyses we are concerned with determining whether the
vulnerability to relapse embodies individuals' concerns about the experience
of psychosis and its implications for the self. In other words, do the
negative appraisals, which seem to confer vulnerability to PPD, also confer
vulnerability to relapse? We contrast, therefore, our vulnerability factors
between the group of relapsing patients (n=11) and the group of
non-relapsing, non-PPD patients (n=31) at the pre-PPD stage.
The relapse group contains those patients whose depressive symptoms at the PPD stage were in fact part of a relapse (see the preceding companion paper), so to test the second hypothesis between-subject comparisons for the aforementioned variables at the pre-PPD stage were conducted. No differences emerged between the non-PPD and relapse groups on beliefs about psychosis (loss, humiliation and entrapment), self-esteem, sociotropy, self-efficacy or self-criticism. Insight did not differentiate between the groups.
In summary, there were no cognitive vulnerability factors for psychotic relapse, in stark contrast to PPD: different processes would seem to be in operation.
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DISCUSSION |
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We conclude that the mechanism underlying PPD is dependent upon the individual's own experience of psychosis and how he/she appraises its implications for the self, specifically in terms of loss, self-blame, humiliation and feelings of entrapment in psychosis.
The application of social ranking theory to depression (Gilbert, 1992) provides an important framework from which PPD may be conceptualised. The effect of powerful and oppressive experiences (or shattering life events, such as psychotic illness) according to this theory initiates an internal defensive mechanism that forces the individual to down-rank and yield to others, particularly if escape is blocked (entrapment). This mechanism may be accompanied by cognitions that are self-attacking, leading to feelings of inferiority and self-blame. This focuses attention on the appraisal of psychosis more than depression vulnerability per se, underlined by the result that those who are depressed are more aware of their psychosis (i.e. insight). Brown et al (1990) argue that any individual can become depressed when given the right context and we suggest that the particular context required for PPD is provided by the appraisal of psychosis where this embodies loss, humiliation and entrapment and the patient's consequent down-ranking.
Methodological issues
In hindsight the utilisation of the DEQ at only one of the follow-up points
after the psychotic episode may have resulted, in the case of dependency and
self-efficacy variables, in an increase of any difference between PPD and
non-PPD patients, because the timing of PPD varied across participants; that
is, it would have been preferable to administer the DEQ at the pre-PPD stage
(when no participants are depressed). However, two arguments can be made to
support the validity of these particular results. First, Blatt et al
(1976) and Zuroff et
al (1999) have
demonstrated that the DEQ variables are indeed vulnerability factors
for depression and are stable. Second, the high correlation between
self-esteem (assessed at all follow-up points) and self-criticism, both of
which discriminated between PPD and non-PPD patients, does suggest that
utilising the DEQ at one follow-up point did provide accurate data. Owing to
the relatively low numbers in the relapsing group (n=11), the results
of the between-group analyses lacked power and should be interpreted with a
degree of caution.
Is psychological vulnerability cause or effect?
These results show that it may be possible prospectively to determine who
will develop PPD by reference to our vulnerability variables. The issue
arises: is this vulnerability cause or effect? There are two possibilities.
First, the vulnerabilities that we have identified may be simply markers or
epiphenomena of past depressive episodes, with no causal value. The high level
of PPD in first episodes seen in this and other studies
(Addington et al,
1998) suggests, on the contrary, that they can be primary. It is
highly likely, however, that repeated depressive episodes will leave their
mark on self-esteem. What is clear is that the study has identified a group of
individuals, when well, who later develop PPD and this largely revolves around
how they perceive the implications of psychosis for their identity and social
status. What is remarkable is how patients' awareness of their illness
(insight) increased during PPD, supporting our belief that
psychosis is indeed what patients are depressed about
(Birchwood & Iqbal,
1998).
The second possibility is that the vulnerabilities that we have identified are a direct result of particularly adverse experiences of psychosis. In fact, no difference was found between the PPD groups in duration of psychosis, number of episodes, etc.; indeed, patients with a first episode of psychosis were more likely to develop PPD. Thus, although we are arguing that a degree of depressive realism about psychosis underpins the appraisals, they do seem to go beyond patients' direct experience and engage the individual's personal interpretation. What was not measured, however, was individuals' premorbid aspirations and functioning and thus the limits that the illness may have objectively placed on functioning. We attempted to examine this by directly focusing upon discrepancies between individuals' ideal and probable self. The hypothesis was partly upheld in that the participants who developed PPD believed that it was significantly more likely that their future selves would include low-status roles than those who were not depressed (i.e. non-PPD). However, no difference was observed between the two groups for their affinity to high-status roles.
It is to be noted that both depressed and non-depressed participants display certain similarities (at the time of testing, similar self-representations were held for both low- and high-status roles: now selves) and that both groups also estimate that they would, in an ideal situation, see themselves as acquiring the same-status roles (like-to-be selves). Indeed, the distinguishing variable appears to be the belief by patients who become depressed (i.e. the PPD group) that their future selves are more likely to be defined by low-status roles.
Our hypothesis is that the implications of psychotic illness force the individual to down-rank and accept a less-valued social role/goal, and that the appraisals underpinning this oppressive mechanism of change for the self result in depression (Gilbert, 1995). We propose that patients who did develop PPD may foresee lower status roles and these may lead to the inner conflict manifested by cognitions of loss, humiliation and entrapment.
The justification for employing the PosSQ as a one-off measure comes from literature supporting the stability of the self-concept in the short term (i.e. the working self-concept) (Marcus & Wurf, 1987). This is defined as the self-concept of the moment and suggests that individuals are heavily influenced in all aspects of judgement, memory and behaviour by their currently accessible thoughts, attitudes and beliefs. Indeed, this definition implies that there is no fixed or static self, but an evolving self-concept influenced by the individual's ongoing social experiences. However, this approach also allows for the self-concept to be viewed as a dynamic and static entity: dynamic owing to the changes in the individual's motivational and social state, and static because core aspects of the self may be unresponsive to such changes (Marcus & Nurius, 1986). This limitation in the methodology would therefore require further replication of the findings, and ideally include an evaluation of the self-concept at more than one follow-up point after the psychotic episode. We would emphasise, however, that this result held even when controlling for depression at the time of testing.
Ogilvie's (1987) suggestion that individuals' appraisal of their well-being is based upon their perception of how close (or distant) they are from their most negative images of themselves (i.e. the undesired self) may well inform the mechanism underlying PPD onset. Such a mechanism may be sensitive to the chronicity of the patient sample in that a greater conflict between like to be and probable/future self may be observable during the early episodes of psychosis and less evident after a number of relapses (i.e. where the more chronic patients, through acceptance and adaptation to the experience of their illness, have lowered their expectations and have a lesser discrepancy between how they are at present and how they wish to be). Hence, a greater conflict in early psychosis may be a likely factor in the reported high incidence of depression and suicide in such cases (Addington et al, 1998). Indeed, 9/18 (50%) first-onset cases in the present study developed PPD in comparison to 19/60 (32%) in the remaining multiple-episode sample (t=3.14, P <0.01). We maintain that the mechanisms of down-ranking and the entrapping effect of psychosis may be comparable to other catastrophic life events (such as major physical disability, which requires the individual to readjust and reformulate the self) and are preceded by initial stages where feelings of anger, dis-belief and negative affect are commonplace (Lazarus & Folkman, 1984). The individual's experience of psychosis and patienthood is just such a debilitating psychological and social assault on the self-concept, especially following first onset, and he/she may display similar reactions.
Therapeutic implications
The social ranking perspective outlined here offers a different emphasis in
the application of cognitive therapy to PPD
(Birchwood & Iqbal, 1998). Fundamentally, cognitive therapy bases its therapeutic approach on the
assumption that cognitions are irrational and may be focused upon when almost
blind to context. Our approach firmly roots the depression in the realities of
psychosis, and lays emphasis on shifting negative appraisals of psychosis and
encouraging practical means of avoiding entrapment by promoting control, for
example, of relapse (Birchwood et
al, 2000a) or voices
(Chadwick et al,
1996). At a service level the experience of compulsory detention
may be viewed as hard evidence for entrapment that can further
entrench this appraisal (Rooke &
Birchwood, 1998). Thus, minimising coercive approaches to care
offers a very tangible way of minimising this most pernicious of appraisals.
Work is a highly valued social role, particularly among the young (who are
particularly prone to PPD), and should be a legitimate focus for mental health
services. The timing of PPD some months after the acute episode is of
particular concern. It is a time when, for most patients, positive symptoms
have remitted and surveillance is lowered. This seems to be the very time when
risk for PPD rises. The vulnerability factors, including a feeling of loss and
a perceived inability to escape, offer guidance to identify those at risk. We
are currently evaluating interventions informed by this model.
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Clinical Implications and Limitations |
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LIMITATIONS
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ACKNOWLEDGMENTS |
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Received for publication December 15, 1999. Revision received June 8, 2000. Accepted for publication June 9, 2000.