The Effects of Cognitive Therapyon Hallucinations in Patients withSchizophrenia

Cognitive therapy was initially developed by Aaron Beck in the 1960s as a short-term psychotherapy for depression (1). It was based on his findings that people suffering from depression exhibit altered cognition along common themes such as low self-esteem, ideas of deprivation, self-criticisms, magnification of problems, self-commands to accomplish tasks which are often large-scale and mutually exclusive, and thoughts of escaping from life's problems. In addition, they tend to employ cognitive distortions such as arbitrary interpretation, selective abstraction, overgeneralization, magnification, minimization, and inexact labelling. These underlying themes and distortions lead to automatic and involuntary depressing and selfdeprecating thoughts in various situations, which in turn lead to emotions such as sadness, anger, embarrassment, and anxiety. Beck postulated that depression could be treated through identification and correction of the patient's idiosyncratic cognitions and underlying depressive themes (2). Since then the cognitive model of therapy has expanded to include treatment of many psychopathologies including schizophrenia. This model suggests that cognitive distortions underlie both mood and behaviour in all psychopathologies; cognitive therapy targets and alters these underlying distortions leading to symptomatic improvement (3). Schizophrenia is a psychotic disorder characterized by two or more of the following for a 1-month period: delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behaviour, and negative symptoms (i.e. affective flattening, alogia, or avolition). Continuous signs of disturbance must be present for at least 6 months, which may include prodromal and residual symptoms in addition to the 1 month of active-phase symptoms (4). While antipsychotic medications are often effective in diminishing symptoms, 10-60% of patients with schizophrenia respond poorly or incompletely to typical antipsychotics and 20-30% of patients taking typical antipsychotics as prescribed will relapse within the first year of maintenance treatment (5). Furthermore, medication non-compliance is a significant barrier to treatment in this population. The Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) showed that 74% of patients discontinued their antipsychotic medication before 18 months, with discontinuation rates ranging from 64%-82% for various antipsychotics (6). Ayuso- Gutierrez et al. report that 73% of schizophrenia exacerbations requiring hospitalization occurred in patients who were non-compliant with medication (7). As such, adjuvant interventions such as cognitive therapy may be beneficial in treating symptoms that are incompletely responsive to pharmacological treatment or in patients who are non-compliant to pharmacological therapy. While schizophrenia symptoms include delusions and hallucinations which may be differentially responsive to cognitive therapy, the disease differs from depressive disorders in that patients with schizophrenia have significant impairment in reality testing and often have a considerable lack of insight (8). These characteristics seem to be in direct opposition to those required for cognitive therapy as recognition of faulty cognition is central to its success. A review of various models of schizophrenia is therefore required to understand the aspects of schizophrenia that are amenable to cognitive therapy. It is widely accepted that schizophrenia is a disorder of dopamine hyperactivity (8), but exactly how this hyperactivity creates symptoms of schizophrenia is yet to be elucidated. Kapur's theory of psychosis as a state of aberrant salience builds on research that the mesolimbic dopamine system assigns salience to experienced events and thoughts and transforms them from neutral occurrences to significant entities. Kapur hypothesises that the increase in dopamine in the mesolimbic system of patients with schizophrenia creates inappropriate salience for both internal and external events. Delusions and disorganized thinking in turn result in an attempt to organize disconnected but seemingly salient events into coherent stories (9). In their literature review, Bentall, Kinderman, and Kaney examine the cognitive distortions in patients with persecutory delusions such as increased attention to threat, a tendency towards external attributions for negative life events, and increased self-esteem when compared to both depressed subjects and controls. They hypothesize that persecutory delusions may be a form of protection from negative information about the self by attributing such information to an external source, thus preserving a positive self-image (10). Cognitive theories of hallucinations have tended to focus on auditory hallucinations, suggesting that they are related to a defect in speech processing. Inconsistent evidence exists for the claim that sub-vocal activity accompanies auditory hallucinations. Gould showed that patients experiencing auditory hallucinations have greater muscular potentials in vocal muscles compared to controls, as measured by electroencephalograph (11). Green and Kinsbourne were unable to replicate these findings. In addition, they had inconclusive results regarding the effects of decreasing sub-vocalizations on auditory hallucinations: humming decreased the number of self-reported auditory hallucinations by 59% while biting the tongue and holding the mouth open was not associated with a significant reduction (12). The relation of auditory hallucinations to subvocalization has led to the interpretation that such hallucinations are self-generated vocalizations misinterpreted as coming from an external source (13). Consistent with this explanation, in his literature review Bentall examines various theories of hallucinations and concludes that a common theme is the misattribution of self-generated thoughts to an external source (14). Paralleling Beck's notion that it is one's perception of a situation that governs emotion rather than the situation itself, Chadwick and Birchwood found that patients' emotional reaction during auditory hallucinations was related to their perception of the quality of the voice (malevolent versus benevolent). Malevolent voices triggered anger, fear, depression, and anxiety and benevolent voices triggered amusement, reassurance, calmness, and happiness. Similarly, patients' perceptions of the auditory hallucinations influenced active engagement with or resistance to the hallucination (15). It is intuitive that delusions may be treated with cognitive therapy as they are distorted beliefs based on misattributions. Following Beck's model, the abnormal cognitions behind the delusional belief can be targeted during therapy. Hallucinations, however, are sensory perceptions rather than faulty cognitions which intuitively makes them less amenable to eradication through cognitive therapy as they are experienced events. Abolishing hallucinations is therefore not the goal of cognitive therapy. Instead, the objective is diminishing the emotional effects that hallucinations have on the patient. This paper reviews a subset of the existing literature on the efficacy of cognitive therapy in treating hallucinations in schizophrenic patients.

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