|Year : 2021 | Volume
| Issue : 2 | Page : 255-264
Efficacy and durability of cognitive behavior therapy in managing hallucination in patients with schizophrenia
Priyanka Shukla1, Debasish Padhi2, KS Sengar3, Abha Singh4, Suprakash Chaudhury5
1 Department of Psychology, CSJM University, Ranchi, Jharkhand, India
2 Department of Psychiatry, Rama Medical College, Ranchi, Jharkhand, India
3 Department of Clinical Psychology, RINPAS, Ranchi, Jharkhand, India
4 Department of Psychology, P.P.N. College, CSJM University, Kanpur, Uttar Pradesh, India
5 Department of Psychiatry, Dr D Y Patil Medical College, Dr D Y Patil Vidyapeeth, Pune, Maharashtra, India
|Date of Submission||22-May-2020|
|Date of Acceptance||04-Jul-2021|
|Date of Web Publication||08-Sep-2021|
Dr. Suprakash Chaudhury
Department of Psychiatry, Dr D Y Patil Medical College, Dr D Y Patil Vidyapeeth, Pimpri,
Pune - 411 018, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: The cognitive behavior therapy (CBT) approach to psychosis is a relatively recent development and focuses directly on the core psychotic symptoms of hallucinations and delusions. Aim: The aim of this study is to assess the efficacy of cognitive behavior therapy in managing hallucination in patients with schizophrenia and to evaluate the generalizability and durability of the therapeutic gains. Materials and Methods: In this confirmatory pre–post assessment study, based on the purposive sampling technique, a sample consisting of 40 (20 for experimental and the other 20 for control group) patients having schizophrenia with core symptoms of hallucination and delusions under treatment as usual were selected and matched on the sociodemographic and clinical variables. For the clinical variables, the Psychotic Symptom Rating Scale and Scale for the Assessment of Positive Symptoms were used. After baseline assessment, the cognitive behavioral program was tailored on the experimental group and patients of both the group were reassessed after the completion of treatment. Follow-up data to see the durability of program were taken from all the patients of experimental and control groups. Results: Cognitive behavior therapy was found to be effective for the treatment of auditory hallucination in schizophrenia. The therapeutic gains in all study variables were found to be maintained or further improving at follow-up which proves that cognitive behavior therapy is durable. Conclusion: Cognitive behavior therapy in conjunction with pharmacotherapy was found to be more effective in improving clinical symptoms of schizophrenia and global functioning compared to pharmacotherapy alone.
Keywords: Cognitive behavior therapy, delusion, hallucination, psychosis, schizophrenia
|How to cite this article:|
Shukla P, Padhi D, Sengar K S, Singh A, Chaudhury S. Efficacy and durability of cognitive behavior therapy in managing hallucination in patients with schizophrenia. Ind Psychiatry J 2021;30:255-64
|How to cite this URL:|
Shukla P, Padhi D, Sengar K S, Singh A, Chaudhury S. Efficacy and durability of cognitive behavior therapy in managing hallucination in patients with schizophrenia. Ind Psychiatry J [serial online] 2021 [cited 2022 Jul 1];30:255-64. Available from: https://www.industrialpsychiatry.org/text.asp?2021/30/2/255/325649
Cognitive therapy, a system developed by Aaron T. Beck, posits that behavior and feelings are determined mainly by the belief system and thinking of the individual. The main focus of cognitive therapy is on understanding distorted beliefs and using techniques to alter maladaptive thinking, while also incorporating affective and behavioral methods. Within the therapeutic process, attention is paid to thoughts that individuals could also be unaware of and to special belief systems. Cognitive behavior therapy (CBT) is an approach designed to vary mental images, thoughts, and thought patterns to assist patients to beat emotional and behavioral problems. It supports the idea that behaviors and emotions are partly the resultants of cognitions and cognitive processes that one can learn to vary.
Schizophrenia is a neurobiological stress-related, disorder leading to disturbances, in form and content of an individual's thought, perceptual processes, affect and social and instrumental behavior. The most important features of schizophrenia include hallucinations and delusion which occur due to neurobiological, neurochemicals, and neuroanatomical changes, but the current literature reveals that the hallucination and delusion are also the outcome of psychosocial and cognitive factors. Some studies have reported that 10%–60% of patients experience hallucinations and delusions that do not respond completely to medication. Therefore, there arise a need to investigate the effectiveness of cognitive-behavioral approach in the management of hallucinations.,, A number of Western studies and meta-analyses have reported the usefulness of CBT in the management of hallucinations in schizophrenia.,,,,,,,,,, However, till date, there are very few studies in India which have explored the effectiveness of CBT in hallucination. In view of the above, the present study was targeted to assess the efficacy of CBT in managing hallucination in patients with schizophrenia and to evaluate the generalizability and durability of the therapeutic gains in the Indian scenario.
| Materials And Methods|| |
This study was carried out at the inpatient department of Ranchi Institute of Neuro-Psychiatry and Allied Sciences (RINPAS), Kanke, Ranchi, a tertiary care psychiatric hospital. The study began after approval from the Institutional Ethical Committee of RINPAS, Ranchi. Each participant gave a written informed consent.
This study was a center-based confirmatory study using the pre- and-post treatment with control group design.
Based on the purposive sampling technique, a sample consisting of 40 (20 for experimental and the other 20 for control group) male patients having schizophrenia with core symptoms of hallucination and delusions under treatment as usual were selected from the different wards of RINPAS. Patients of both the groups were matched on sociodemographic and clinical variables.
Participant's inclusion and exclusion criteria
Patients diagnosed with schizophrenia (as per International Classification of Disease-10-Diagnostic Criteria for Research criteria) having auditory hallucination.
Male patients between the age range of 20–50 years.
Patients who gave informed consent.
Patients with minimum primary level of education.
Patients with other comorbid psychiatric, neurological and physical illness.
Patients with mental retardation.
Patients who are uncooperative.
Tools for assessment of the patient
Sociodemographic and clinical data sheet
This was a self-designed pro forma especially designed for this study. It contains information about sociodemographic variables such as age, sex, religion, education, marital status and occupation including other clinical details such as relevant past and family history, presence of co-morbid conditions, mental status examination, and diagnosis.
Scales to measure dimension of hallucinations and delusions: The Psychotic Symptom Rating Scale
Psychotic Symptom Rating Scale (PSYRATS) is a rating scale developed by Haddock et al. This scale was developed to recognize the complexity of hallucination and delusions. It also measures the severity of these symptoms. It consists of two sets of scales, one for the auditory hallucinations and second for the delusions. The subscale of auditory hallucination has 11 items and to the scale for delusion has six items. Severity is rated using a 5-point scale.
Scale for the assessment of positive symptoms
Scale for the Assessment of Positive Symptom (SAPS) is a 34-item scale, developed by Andreasen, for the assessment of positive symptoms that occur in individuals with schizophrenia, including bizarre behavior, delusions, positive formal thought disorder, and hallucinations. The mode of administration of the SAPS is through a general clinical interview, combined with some standardized questions. It's a 6-point rating scale.
Global assessment of functioning
The Global Assessment of Functioning (GAF) scale is a widely used scale to assess overall level of functioning during a particular time. Functioning takes into account a composite of three major areas: occupational functioning, social functioning, and psychological functioning. GAF scale is split into 10 ranges of functioning, based on a continuum of mental health and mental disorder; maximum score is 100 which represents the highest level of functioning in all area.
The cognitive behavior therapy package for intervention
The intervention took place in two stages. The primary stage was assessment and informative phase. The second stage was the modification of patient's maladaptive belief regarding delusions and hallucinations and applying appropriate techniques to scale back these symptoms, depending on the suitability of the patient. Approximately 16–20 sessions were required.
Assessment phase – It took between 1 and 3 sessions, it included-
Detailed mental status examination and rating scales.
A cognitive behavior assessment of the hallucinations, which assessed the frequency and duration of the voices, their content, coping strategies, physical characteristics and origin of the voices, as well as the person's beliefs and attribution regarding their voices.
Treatment – Stage 2: Intervention with hallucination-
Psychoeducation and normalization.
Clarified the exact nature of the voices and any linked symptoms.
Worked on reattribution with the person's explanation of voices hearing, and test it out.
Collaboratively generated other possible explanations and test these out.
Used a voice diary to explore triggers and fluctuations in the voice hearing experience. Undertake simple environmental change if appropriate.
Systematically started work with coping strategies to reduce auditory hallucinations.
Worked to reduce linked affective exacerbators (anger, frustration, anxiety).
Explained any linked schemas, and attempted to alter dysfunctional schemas that are sustaining hallucinations.
Reattribution of auditory hallucinations
With the aim to allow the patients to consider the possibility that the voices might be their own thoughts.
Specific strategies to deal with hallucinations
Few techniques are described below which were used by the therapist as per need of the patients.
This is often a very basic cognitive strategy that rests on the concept that we will only target one thing at a time, so if we specializein something neutral or pleasant, we will avoid getting trapped with negative thoughts and urges. Distraction techniques include various strategies; for example: humming a single note, reading aloud, arithmetic task, mental tasks, talking with others, saying “stop” and naming objects, saying “stop” and “go away,” any activity that diverts attention away from the voices can include as distraction techniques. The therapist used techniques according to the interest of the patients.
Focusing and exposure
These techniques simply involve, letting the voice be and relax with it. Helping the client to expose himself to the content of voices, to reduce the associated anxiety. Such strategies essentially involve the individual monitoring or recording the characteristics or content of voices. This might reduce the anxiety associated related to the voices, and convey to the patient's awareness that there are fluctuations within the severity of the voices. This further help the patient to identify the affect associated with the voices and their consequential responses to them. Symptoms are then targeted using traditional cognitive behavioral techniques.
It involves many techniques but in the present study only relaxation training is include.
Testing beliefs about control
A useful strategy is to use a procedure whereby the patient and therapist learn to engineer situations to start or increase the probability of hearing voices, and then to stop or reduce them. In this way, the patient gains a surprising degree of control over the voice. The initial assessment provides information about cues that provoke voices for a particular individual; concurrent verbalization is known to stop or diminish voices temporarily. This information is combined in the following steps:
- Identify cues that increase and reduce voices
- Suggest the notion that “control” needs the demonstration that voice activity may be turned up/on or down/off
- In sessions, embolden the subject to initiate or increase voice activity for brief periods and then reduce or stop it
- Elicit changes within the patient's belief about his control over the voices.
Information about socio-demographic variables and clinical details were collected using the socio-demographic and clinical data sheet from the drawn sample selected according to the inclusion and exclusion criteria. PSYRATS and SAPS were administered to assess the severity of the hallucination. The GAF scale was administered to assess the level of functioning at the time of assessment. The drawn samples of 40 patients were further subdivided randomly into two groups of 20 patients each. First group, i.e., experimental group, was given cognitive behaviour treatment with treatment as usual and the second group, i.e., control group, was only on treatment as usual, waitlisted. The techniques for cognitive behaviour therapy were used which consisted 25–30 sessions lasted approximately 1 h each. The cognitive behavioral program was tailored according to the need of the patients. Patients of both the group were re-assessed after completion of 12 weeks of training. Follow up data to see the durability of program were taken from all the patients of intervention and control group, who came for follow up after 12 weeks.
Data were entered into a computer and analyzed using IBM SPSS software package (version 16.0; IBM, Chicago, IL, USA). Qualitative data were described using number and percent. Quantitative data were described using mean and standard deviation comparison between different groups as regards categorical variables was done with the Chi-square-test. When more than 20% of the cells have expected count <5, correction for Chi-square was conducted using Fisher's exact test. For ordinal data, comparison between two independent groups was made using the Mann–Whitney test, while for comparison at different periods the Wilcoxon signed-ranks test was applied. Significance of the obtained results was judged at the P < 0.05 level.
| Results|| |
The mean age of the participants from the experimental group and control group was 33.05 ± 1.45 and 29.45 ± 1.77 years, respectively. There was no significant difference found between the experimental and control group regarding age (u = 148; z = 1.41). All of the participants were male. Mean education of the participants from the experimental group and control group was 9.25 ± 0.42 and 8.95 ± 0.35 years, respectively. There was no significant difference found between experimental and control groups regarding education (u = 189; z = 0.31).
[Table 1] shows the comparison between the experimental and control groups on other sociodemographic variables and clinical characteristics. It shows that no significant difference was found between the experimental and control groups in the sociodemographic characteristics of marital status, residence, family type, socioeconomic status, and income. Only significant difference was found between the experimental and control groups in occupation (at <0.01 level) that might be during illness period but before becoming sick they were participating in work. Majority of the patients had no history of major medical illness and no family history of psychiatric illness. Regarding history of psychiatric illness, patients were approximately equally divided. Both the groups were on treatment as usual. Hence, the experimental and control groups were matched to each other with respect to their clinical characteristics.
|Table 1: Demographic and clinical characteristics of the experimental group and control group|
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Comparison on the area of hallucination on the SAPS between experimental and control group at baseline shows that there was no significant difference between the experimental and control group on any of the elements of hallucination. Like, in auditory hallucination, voices commenting, voices conversing, and global rating of hallucination. Few symptoms of hallucination were not seen in patients of both the group such as somatic, olfactory, and visual hallucination [Table 2]. Comparison on the area of hallucination on PSYRATS between the experimental and control group at baseline shows that both the group does not differ significantly on their baseline scores in the areas of frequency, duration, location, and loudness of auditory hallucination [Table 3]. There was no significant difference between the experimental group and control group in their global functioning on the GAF [Table 4].
|Table 2: Baseline status of clinical symptoms of the experimental and control group on Scale for the Assessment of Positive Symptom dimension of hallucination|
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|Table 3: Baseline status of clinical symptoms of the experimental and control groups on Psychotic Symptom Rating Scale dimension of hallucination|
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|Table 4: Baseline status of the experimental and control groups on global assessment of functioning|
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Durability of cognitive behaviour therapy
To find out the durability of CBT, comparison between after intervention and on follow-up scores for the status of clinical symptoms and global functioning for the experimental and control group were done using Wilcoxon sign-rank test. [Table 5] reveals that there was no significant difference between postassessment scores and on follow-up scores of the control group on any subarea of the hallucination of SAPS. Surprisingly, it was noticed that in the area of voices conversing, mean scores in the follow-up had gone up despite taking the medicine continuously.
|Table 5: Status of clinical symptoms on Scale for the Assessment of Positive Symptom dimension of hallucination in the control group on postassessment and on follow-up|
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[Table 6] reveals that the therapeutic gains obtained after intervention were not only maintained on follow-up but also further significant improvement was noticed on the areas of auditory hallucination and global rating of hallucination.
|Table 6: Status of clinical symptoms on Scale for the Assessment of Positive Symptom dimension of hallucination in the experimental group on after intervention and on follow-up|
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[Table 7] shows that there was no significant difference between postassessment scores and on follow up in the control group on any of the subscales of PSYRATS. However, in the area of re-origin of voices, the reverse trend was seen on follow-up mean scores, which suggests severity level was gone more on this particular area.
|Table 7: Status of clinical symptoms on Psychotic Symptom Rating Scale dimension of hallucination in the control group on postassessment and on follow-up assessment|
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[Table 8] reveals that there were no significant differences between both the scores of experimental group in all the areas of hallucinations, although analysis of mean scores suggests that further improvement from the after intervention levels has also been noticed approximately in all the areas on follow-up.
|Table 8: Status of clinical symptoms on Psychotic Symptom Rating Scale dimension of hallucination in the experimental group on after intervention and on follow-up|
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[Table 9] shows that there was no significant difference between postassessment scores and on follow-up scores of the control group on GAF. Analysis of mean scores suggests that minute deterioration has been seen on follow-up scores.
|Table 9: Status of global assessment of functioning in the control group on postassessment scores and on follow-up assessment scores|
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[Table 10] shows the status of GAF of the experimental group after-intervention and on follow-up. It shows that the therapeutic gains obtained after intervention were not only maintained but also further improved on follow-up at significant levels. The significant difference was at 0.01 levels.
|Table 10: Status of global assessment of functioning in the experimental group on after-intervention scores and on follow-up assessment scores|
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| Discussion|| |
Over the last two decades, researchers have made progress in identifying and using effective treatments, including psychotherapy, pharmacotherapy, and combined treatments. Evidence is clear that psychotherapies and pharmacological treatments can be very helpful to reduce the symptomatology of the patients suffering from schizophrenia. CBT for schizophrenia is an evidence-based treatment primarily designed to focus on the symptoms of psychosis such as hallucinations and delusions that persists despite appropriate treatment with antipsychotic medication. Meta-analysis suggests that CBT improves psychotic symptoms, negative symptoms, and functional outcome.
[Table 5] shows the status of the control group and [Table 6] shows the status of the experimental group. In the control group, there were no significant differences found after intervention to follow-up scores. In the control group, the dimension of the hallucination, the findings further indicate that patients of schizophrenia having positive symptoms were not improved further after discharge. Although they were on continuous treatment (medicine), status of the positive symptoms remains same, which further interfere on rehabilitation of schizophrenic patients having hallucination and delusion and also prevents the person from carrying out their routine responsibilities. On the other hand, in the experimental group, a statistically significant difference was found at 0.05 level on the area of auditory hallucination and in the global rating of the hallucination, whereas in other areas, no significant differences were found. It shows that the therapeutic gains obtained after interventions were maintained on follow-up and patients were gained life skills successfully. Therefore, the intervention program was not only efficacious and generalizable but also durable. The findings of the present study are consistent with the Sevi et al., who reported that the frequency and distress of hallucination and delusion and patient's preoccupation with them and the severity of hallucination and delusion in most cases did not change significantly posttreatment in the control group, whereas they did in the treatment group. Total positive symptoms scores were significantly decreased in both the groups but its decrease greater in the treatment group. Belief in voices, control of voices, and ability to cope with voices did not differ posttreatment in either group. However, the findings of coherence with meta-analysis concluded that CBT did not significantly reduce the rate of relapse and readmission to hospital, when compared with standard care (antipsychotic therapy). It is not in the favor of present study's findings. However, significant advances of CBT were noted in enhancement of discharge rate from the hospital. Furthermore, an improvement in mental state has been demonstrated (defined as an improvement on psychotic symptoms while at least 40%–50% as measured by brief psychiatric rating scale). CBT with focus on announcing compliance also have been some benefits in terms of frosting a positive attitude was of medication, is in line of the findings of the present study. The reason for available result in CBT may be due regards to focus of treatment as some are focused on psychotic symptoms and other on compliance.
[Table 7] and [Table 8] show the status in the dimension of the hallucination of PSYRATS. [Table 7] shows the status of the control group and [Table 8] shows the status of the experimental group. No significant difference was observed within the control group even after active pharmacological treatment. On the other hand, within the experimental group also, there was no significant difference found from after assessment to follow-up. However, the mean scores show that the therapeutic gains obtained after interventions were maintained on follow-up. Although analysis of mean scores suggests further improvement in the experimental group as compared to the control group, further improvement is noticed in the areas of duration and loudness of auditory hallucination, amount of negative content, degree of negative content, intensity of distress, and disruption to life. These result supports efficacy of cognitive behavior therapy in managing hallucination and delusions. The findings of the present study indicate that the gains obtained at the end of the intervention program were still maintained on follow-up, and in some cases, they were further improving. Therefore, the intervention program was not only efficacious and generalizable but also durable.
The findings of the present study are consistent with the findings of Thomas et al. in which PSYRATS and PANSS were applied before and after therapy to 33 people with schizophrenia receiving CBT for auditory hallucinations in a specialist clinic. The results showed significant improvements posttreatment on the PSYRATS and PANSS Positive and General Scales. The findings of the present study are also consistent with the finding of Nowak et al., Peters et al., and Rizk et al.
The status of global functioning in the experimental and the control group after intervention and on follow-up is shown in [Table 9] and [Table 10]. The findings of the control group show no significant differences from postassessment to follow-up. While analysis of mean scores suggest, further decline in global functioning in the control group. On the other hand, findings of the experimental group show improvement from after intervention to follow-up. The findings of the experimental group given in [Table 10], it shows statistically significant difference at 0.01 level. This shows further improvement in intervention group's functioning and high degree of durability of gains through the cognitive-behavioral intervention program used in the present study.
The findings of the current study are consistent with the findings of Zimmermann et al. They performed a meta-analysis of 14 studies published between 1990 and 2004 that included 1484 patients. The results revealed that, in contrast to other adjunctive measures, CBT significantly decreased positive symptoms in schizophrenia. Further CBT was more beneficial for patients with an acute psychosis as compared to chronic psychosis (effect size of 0.57 vs. 0.27). Zimmermann et al. concluded that CBT could be a useful adjunctive treatment for positive symptoms in schizophrenia. Similarly, Candidal et al. concluded that the immediate and long-term efficacy of CBT reduces the positive and negative symptoms in schizophrenia.
Turner et al. in a meta-analysis found that efficacy of CBT for auditory hallucinations and delusions is sufficient and stable across comparisons. Similarly, in a study Emmanuelle et al. found CBT as positive and potentially psychological service for clients with psychosis. Similar findings were also noticed by Maria et al. and they found CBT as an effective tool in the management of auditory hallucinations. While Jauhar et al. noticed effectiveness of CBT in schizophrenia but in small range. Therefore, on the basis of available reviews, there is still a lot should be done in future.
The study had a few limitations. The sample size was modest. The study was at one location only. The assessments were not blinded. Future studies should look into these aspects.
| Conclusion|| |
In the present study, we have tried to assess the efficacy and durability of cognitive-behavioral therapy in patients having hallucination in schizophrenia. The intervention program used combine cognitive and behavioral components. The primary aim of the treatment is helping the patient to cope with hallucinations. The package used for the treatment was found significantly effective to improve the cases. The improvements seen after intervention were found to be maintained and in some areas further improving after a follow-up period of 3 months. This trend was evident in all study variables, namely clinical symptoms and global functioning. This shows that the therapeutic gains obtained with the cognitive-behavioral intervention were durable. These findings support the feasibility of implementing cognitive-behavioral intervention with the pharmacological treatment may be beneficial for patients with significant functional and symptomatic impairments. But there is scope in the future that more studies should focus on the mechanism of CBT for personal recovery and the factors that influence the long-term effects of CBT.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Beck AT, Rector NA, Stolar N, Grant P. Schizophrenia: Cognitive Theory, Research, and Therapy. New York: Guilford Press; 2008.
Lieberman JA, Stroup TS, McEvoy JP, Swartz MS, Rosenheck RA, Perkins DO, et al.
Effectiveness of antipsychotic drugs in patients with chronic schizophrenia. N Engl J Med 2005;353:1209-23.
Chaudhury S. Hallucinations: Clinical aspects and management. Ind Psychiatry J 2010;19:5-12.
] [Full text]
Kumar S, Soren S, Chaudhury S. Hallucinations: Etiology and clinical implications. Ind Psychiatry J 2009;18:119-26.
] [Full text]
Turner DT, Burger S, Smit F, Valmaggia LR, van der Gaag M. What constitutes sufficient evidence for case formulation-driven CBT for psychosis? Cumulative meta-analysis of the effect on hallucinations and delusions. Schizophr Bull 2020;46:1072-85.
Emmanuelle P, Tessa C, Deborah A, Louise CJ, Daniel S. The long- term effectiveness of cognitive behaviour therapy for psychosis within a routine psychological therapies service. Front Psychol 2015;6:1658.
Maria P, Franco DC, Stefano V, Maria LP, Roberto A, Ornella S, Macro A. Cognitive behaviour therapy for auditory hallucinations in schizophrenia: A review. World J Psychiatry 2016;6:372-80.
Jauhar S, McKenna PJ, Radua J, Fung E, Salvador R, Laws KR. Cognitive-behavioural therapy for the symptoms of schizophrenia: Systematic review and meta-analysis with examination of potential bias. Br J Psychiatry 2014;204:20-9.
Pontillo M, De Crescenzo F, Vicari S, Pucciarini ML, Averna R, Santonastaso O, et al.
Cognitive behavioural therapy for auditory hallucinations in schizophrenia: A review. World J Psychiatry 2016;6:372-80.
Burns AM, Erickson DH, Brenner CA. Cognitive-behavioral therapy for medicatio nresistant psychosis: A meta-analytic review. Psychiatr Serv 2014;65:874-80.
van der Gaag M, Valmaggia LR, Smit F. The effects of individually tailored formulation-based cognitive behavioural therapy in auditory hallucinations and delusions: A meta-analysis. Schizophr Res 2014;156:30-7.
Sommer IE, Slotema CW, Daskalakis ZJ, Derks EM, Blom JD, van der Gaag M. The treatment of hallucinations in schizophrenia spectrum disorders. Schizophr Bull 2012;38:704-14.
Gottlieb JD, Romeo KH, Penn DL, Mueser KT, Chiko BP. Web-based cognitive-behavioral therapy for auditory hallucinations in persons with psychosis: A pilot study. Schizophr Res 2013;145:82-7.
Propst A. The effects of cognitive therapy on hallucinations in patients with schizophrenia. Mcgill J Med 2011;13:55.
Thomas N, Hayward M, Peters E, van der Gaag M, Bentall RP, Jenner J, et al.
Psychological therapies for auditory hallucinations (voices): Current status and key directions for future research. Schizophr Bull 2014;40 Suppl 4:S202-12.
World Health Organization. The ICD-10 Classification of Mental and Behavioral Disorders, Diagnostic Criteria for Research. Geneva: WHO; 1993.
Haddock G, McCarron J, Tarrier N, Faragher EB. Scales to measure dimensions of hallucinations and delusions: The psychotic symptom rating scales (PSYRATS). Psychol Med 1999;29:879-88.
Andreasen NC. Scale for the Assessment of Po7sitive Symptoms (SAPS) Iowa City, IA: University of Iowa; 1984.
Wykes T, Steel C, Everitt B, Tarrier N. Cognitive behavior therapy for schizophrenia: Effect sizes, clinical models, and methodological rigor. Schizophr Bull 2008;34:523-37.
Sevi OM, Sutcu AT, Kose GG. A pilot study on the effectiveness of a group-based cognitive-behavioral therapy program for coping with auditory hallucinations. Turk J Psychiatry 2011;22:26-34.
Thomas N, Susan R, John F, Frances S, David C. Cognitive behavioural therapy for auditory hallucinations: Effectiveness and predictors of outcome in a specialist clinic. Psychol Med 2010;40:9-24.
Nowak I, Sabariego C, Świtaj P, Anczewska M. Disability and recovery in schizophrenia: A systematic review of cognitive behavioral therapy interventions. BMC Psychiatry 2016;16:228.
Peters E, Crombie T, Agbedjro D, Johns LC, Stahl D, Greenwood K, et al.
The long term effectiveness of cognitive behaviour therapy for psychosis within a routine psychological therapies service. Front Psychol 2015;6:1658.
Rizk DN, Salamaa H, Molohkiaa T, Kassemb L. Study of effectiveness of brief cognitive behavioral therapy for auditory hallucinations in schizophrenia. Egypt J Psychiatry 2016;37:53-8.
Zimmermann G, Favrod J, Trieu VH, Pomini V. The effect of cognitive behavioral treatment on the positive symptoms of schizophrenia spectrum disorders: A meta-analysis. Schizophr Res 2005;77:1-9.
Candidal M, Campos C, Monteiro B, Paes F, Machado S. Cognitive behavioural therapy for schizophrenia: An overview on efficacy, recent trends and neurobiological findings. Med Express 2016;3:5.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]