An estimated 25% to 50% of patients with schizophrenia experience residual symptoms, including medication-resistant delusions.1,2 These persistent symptoms contribute to the chronic, debilitating course of the illness. Delusions are defined as “fixed false beliefs” that have the following attributes3:
• Certainty: held with absolute conviction
• Incorrigibility: not changeable by compelling counterargument or proof to the contrary
• Impossibility or falsity of content: implausible, bizarre, or patently untrue convictions
In addition, a delusional belief is generally not shared by other members of a person’s culture or community.4
According to this definition, delusional patients would not be expected to express doubt about their delusional beliefs. However, recent research suggests that delusions in fact are multidimensional and that they vary over time in degree of conviction, distress, preoccupation, action, insight, and interference with daily functioning.5-7 Some of the factors thought to contribute to the origin of delusions and maintenance of delusional conviction are belief inflexibility and a “jumping to conclusions” bias.5,8-17
Studies have shown that cognitive-behavioral therapy (CBT) reduces acute and medication-resistant psychotic symptoms, including delusional beliefs.18-26 In this setting, CBT aims to enlist the patient in a collaborative investigation of evidence for and against his or her beliefs, using the A-B-C model, where:
• A is an event (such as a “voice”)
• B is a belief about the meaning of A (the voices are omnipotent and must be obeyed)
• C is the emotional and behavioral consequence of this belief (fear and social isolation)
In psychosis, A and B are often fused in the patient’s mind.
The clinician attempts to separate event from belief about event by gently kindling doubt about the delusions and therefore decreasing the patient’s belief inflexibility. Garety and colleagues27 found that among patients who received CBT, the ability to acknowledge “the possibility of being mistaken” about their delusional beliefs was a strong predictor of success of therapy. In a small study of cognitive therapy for delusions, Sharp and colleagues8 found that changes in items of the Maudsley Assessment of Delusions Schedule (MADS), a scale that measures conviction in delusions, correlated with therapeutic improvement. More recent evidence suggests that women with schizophrenia and a low level of conviction in their delusions are most likely to respond to brief CBT.9
While CBT for psychosis attempts to increase the patient’s doubts about his delusional beliefs during treatment, little is known about preexist-ing doubts that patients may harbor before receiving CBT. In a study we undertook at the State University of New York Medical Center, the goal was to examine doubts patients might have about their delusions before their beliefs were challenged with CBT. More specifically, the study aimed to determine (1) the feasibility of measuring doubt about delusions in a single cross-sectional interview; (2) the reasons patients doubted their delusions; and (3) the correlation between degrees of doubt and conviction with other dimensions of psychosis.
We hypothesized that some degree of doubt may be present before delusions are challenged in treatment and that this doubt may be elicited in a single semistructured interview when the interviewer uses an open, nonconfrontational approach. We predicted that patients might report both conviction and doubt simultaneously, and that low levels of doubt would correlate with higher scores on measures of severity of psychotic illness.
■ Cognitive-behavioral therapy has been shown to reduce acute and medication-resistant psychotic symptoms, including delusional beliefs.
■ Some degree of doubt may accompany delusions before they are challenged in treatment; such doubts may be elicited in a single semistructured interview when the interviewer uses an open, nonconfrontational approach.
■ It is possible that the capacity to doubt requires cognitive flexibility and the ability to integrate contradictory evidence—a cognitive capacity that may be impaired in patients with negative symptoms and neuropsychological impairments.
First, we conducted a brainstorming session and generated a pilot list of possible reasons a person, psychotic or nonpsychotic, might doubt a belief. For example, someone might doubt a belief if a person he trusts questions it. Initial interviews were carried out with 5 delusional patients on an acute inpatient ward using the draft reasons for doubt (RFD) checklist to test the feasibility of the research protocol. Reasons for doubt elicited in the pilot session not already on the checklist were added to the final version of the RFD checklist (Table 1).
In the second phase, 25 patients with delusions were recruited by their treating clinicians. Subjects were selected on the basis of their DSM-IV diagnosis of schizophrenia and/or schizoaffective disorder, on their ability to engage in an interview, and on their ability to provide written informed consent. Patients with a primary diagnosis of alcohol(Drug information on alcohol) and substance dependence, those younger than 18 or older than 65 years, or those with severe cognitive disorganization rendering a coherent conversation impossible were excluded from the study. All patients in the study had a history of relapsing psychosis and had received neuroleptic medication.
We conducted a 1-hour cross-sectional interview with each patient. After establishing rapport, the investigator discussed the patient’s delusions and explored what doubts he might have about his beliefs. The following were completed on the basis of the results of the interview:
• The MADS28 to measure degree of conviction and associated factors, clinician-rated during the interview
• Part B of the Psychotic Symptoms Rating Scales (PSYRATS)29 to provide a dimensional measure of delusions and functional impairment from delusions
• The Positive and Negative Syndrome Scale (PANSS)30 to provide information about severity of positive, negative, and general psychopathology symptoms
• The RFD checklist (Table 1)
Reasons for doubt
The first item on the MADS, “How sure are you about X?” commonly elicited descriptors such as very, almost, totally. Patients were then asked to rate their conviction on a linear scale from 0% to 100%. When those who had said “completely” were asked to rate their conviction, some estimated a number close to 100% but not 100%. This result suggests that asking a patient to respond on a linear percentage scale may elicit more expression of uncertainty than a verbal response.
The authors grouped the patient’s degree of conviction into 1 of 3 categories: (1) absolute; (2) high; or (3) medium-low, for purposes of comparison. Eight patients (32%) were absolutely convinced (100%) of their delusion and expressed no doubt; 8 (32%) had high conviction (70% to 99% on the 0% to 100% scale); and 9 (34%) had medium to low conviction (50% or less on the 0% to 100% scale). Mean symptom severity scores according to the PSYRATS and PANSS are shown in Table 2. The level of conviction and the patient’s symptom severity scores are shown in Table 3.
All but 2 patients (23 of 25) had at least 1 RFD. Patients commonly had more than 1 RFD, in which case all responses given were recorded. Even patients who said they were 100% convinced of their delusions reported possible reasons for doubting their beliefs. Table 1 shows the itemized RFD checklist and the frequency with which each category of response was present in our sample. The Figure shows the most frequent RFD by degree of conviction group.
The individuals who had 100% conviction were asked: “In case you were to doubt X, what would most likely be the reasons?” Four patients were able to provide a hypothetical RFD, and others were able to de-scribe an RFD they once had in the past; only 2 had no RFD.
A statistical analysis (Pearson correlation and chi-square frequencies) was performed with SPSS 12.0 for Windows to look for correlations between degree of doubt, RFD, subjective distress, and clinical ratings according to PSYRATS and PANSS. RFD correlated with level of conviction for items coded as FFD (family, friends, doctor, or some significant other kindled doubt), CE (person aware of contradictory evidence), and St (aspects of the psychotic experience felt inherently strange, puzzling, or confusing) (P < .05). A significant negative correlation between doubt and negative symptoms was observed (Table 4), ie, the higher the negative symptoms score, the less doubt expressed about delusions.
In keeping with our hypothesis, and contrary to the conventional wisdom that delusions are fixed beliefs held with absolute certainty, 23 of the 25 patients (92%) expressed at least 1 reason for doubting their delusions. In our sample, a single cross-sectional interview was enough to elicit the patient’s uncertainties. The most common RFD by far was that a family member or some other person of significance questioned the delusion. This RFD occurred most frequently in the medium-low conviction group. It may be that patients have a greater tendency to doubt delusions when a trusted family member expresses disbelief, or that individuals with less conviction (for some other reason) are more receptive to hearing the doubts of significant others.
In line with our hypothesis, higher negative symptom scores correlated with less doubt about delusions. It is possible that the capacity to doubt requires cognitive flexibility and the ability to integrate contradictory evidence—a cognitive capacity that may be impaired in patients with negative symptoms and neuropsychological impairments.31 This is consistent with earlier findings that indicate that symptoms such as affective blunting and alogia are associated with poor CBT outcomes for residual symptoms in schizophrenia.32
Patients with high positive symptom scores expressed more doubt about delusions than patients with high negative symptoms scores, which suggests that patients with positive symptoms may be more amenable to having doubt mobilized in CBT. Keep in mind, however, that the inclusion criteria, such as willingness to participate in this study, pose a selection bias and may therefore not represent the full spectrum of the severity of psychotic illness.
Our study suggests that most delusional patients, even those with high positive symptom scores, may have at least 1 RFD that precedes a clinical intervention specifically directed toward encouraging doubt. These preexisting “islands of doubt” may offer a useful foothold to begin the CBT process. The therapist can initiate treatment by allying with the patient’s antecedent uncertainties; later he can challenge beliefs the patient holds with more certainty.
This study has implications for potential modifications in the conceptualization and definition of delusions. Further longitudinal research is needed to determine how useful this particular approach might be in CBT for psychosis.