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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 4  |  Issue : 1  |  Page : 56-62

Frequency and characterization of depression in schizophrenia


1 Consultant Psychiatrist, Dr Pradeep's Clinic, Coimbatore, India
2 Department of Psychiatry, Mahatma Gandhi Medical College, Sri Balaji Vidyapeeth University, Bahour, Puducherry, India

Date of Submission21-Sep-2019
Date of Decision08-Nov-2019
Date of Acceptance09-Nov-2019
Date of Web Publication30-May-2020

Correspondence Address:
Dr. Avudaiappan Sankaran
Department of Psychiatry, Mahatma Gandhi Medical College, Sri Balaji Vidyapeeth University, Pillaiyarkuppam, Bahour, Puducherry
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/aip.aip_59_19

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  Abstract 


Context and Aims: The prevalence of depression in schizophrenia has been reported to be varying according to the stage of illness (early vs. chronic) and state (acute or postpsychotic). The presence of positive symptoms, extrapyramidal side effects, and insight have been said to predispose depression in a stable patient with schizophrenia. However, not many Indian studies have examined depression in patients with stable schizophrenic symptoms. Thus, we aimed to study the prevalence of depression and its correlates in a sample of stable patients with schizophrenia. Subjects and Methods: Eighty subjects of both genders, attending a tertiary care center, were consecutively taken up for the assessment. A semistructured pro forma was administered for all the subjects after getting informed consent. Positive and Negative Symptom Scale, Calgary Depression Scale for Schizophrenia (CDSS), Hamilton Depression (HAMD) Rating Scale, Extrapyramidal Symptom Rating Scale, Schedule for Assessment of Insight (SAI), and Global Assessment of Functioning Scale (GAF) were used to assess the patients. Results: In this study population, 34.5% had depressive symptoms. The study group had mild depression associated with schizophrenic psychopathology. The study populations did not have significant extrapyramidal symptoms during the assessment. The CDSS score and HAMD score had a significant positive correlation with SAI score. HAMD score had a negative correlation with GAF. Conclusions: This study demonstrates that patients with schizophrenia have significant depressive symptoms. These depressive symptoms appear to be independent of extrapyramidal symptoms and correlate positively to schizophrenic psychopathology. Poor insight may have led to low severity of reported depressive symptoms.

Keywords: Calgary depression rating scale, depression, schizophrenia


How to cite this article:
Pradeep M, Sankaran A. Frequency and characterization of depression in schizophrenia. Ann Indian Psychiatry 2020;4:56-62

How to cite this URL:
Pradeep M, Sankaran A. Frequency and characterization of depression in schizophrenia. Ann Indian Psychiatry [serial online] 2020 [cited 2020 Oct 19];4:56-62. Available from: https://www.anip.co.in/text.asp?2020/4/1/56/285508




  Introduction Top


The prevalence of depressive disorder in schizophrenia has been reported to be around 40%, which varies according to the stage of illness (early vs. chronic) and state (acute or postpsychotic).[1] In acute episodes, the rates are as high as 60%, while in postpsychotic schizophrenia, the rates of moderate-to-severe depression vary between 20% in chronic schizophrenia and 50% following treatment of first episode.[2] Although depression had been seen as a good prognostic indicator historically,[3] evidence points to the contrary.[2],[4] Depression is the most common predictor of suicide in patients with schizophrenia.[5] Conley et al. reported that those with schizophrenia and depression were significantly more likely to relapse, to be a safety concern (violent, arrested, victimized, and suicidal), have greater substance-related problems, and report poorer life satisfaction, mental functioning, family relationships, and medication adherence.[1]

The summation of biological, psychological, and environmental risk factors results in the development of depression in schizophrenia. There is a considerable overlap between the genetic predisposition for affective disorder and schizophrenia.[6],[7] A family history of mood disorders in patients with schizophrenia increases their chances of developing depressive symptoms. In the background of this genetic vulnerability, stress appears to play a major role. Stress factors vary in quality and quantity. They can be biological or psychosocial. It is possible to consider that the stress of depression itself can precipitate an episode of schizophrenia in a vulnerable person with its disturbing influence on hormones, monoamines, and sleep.

However, some researchers feel that it is the interference produced by neuroleptics on the dopamine reward pathway that is responsible for the appearance of the symptoms.[8] This is refuted by the fact that a prodromal state presents with symptoms indistinguishable from depression [9] and the finding that neuroleptic treatment has helped improve depressive symptoms in schizophrenia is significantly amalgamating these depressions with schizophrenia.[10]

As Conley et al. pointed out, the depression rates and presentation vary among acutely ill and stable patients with schizophrenia.[1] Various factors have been said to predispose depression in a stable patient with schizophrenia. Although phenomenologically the depressive symptoms seem to mimic the negative symptoms (NSs), studies are not in favor of a positive correlation between these two variables. On the contrary, positive symptoms (PSs) have been demonstrated to have a positive correlation with depressive symptoms appearing in these patients.[11],[12] Tharyan and Kuruvilla studied the correlates of depressive symptoms in patients with schizophrenia and found that retained insight and lower NS scores were more common accompaniments of a mild depressive state developing in these patients.[13] Although there is an apparent phenomenological overlap between the depressive symptoms and extrapyramidal symptoms, no positive correlations have been documented.

Tharyan and Kuruvilla found that retained insight is one of the factors associated with the development of depressive features in schizophrenia.[13] Apart from this, studies have shown that the treatment of patients with schizophrenia with insight-focused cognitive behavioral therapy (CBT) and non-CBT approaches targeting insight increased the incidence of depression in these patients.[14],[15] Atypical antipsychotics, which are currently the mainstay of the treatment, have direct antidepressant effect according to some studies.[10] However, not many Indian studies have examined depression in patients with stable schizophrenic symptoms.

Thus, we aimed to study the prevalence of depression and its correlates in a sample of stable patients with schizophrenia attending the outpatient department of a tertiary care center.


  Subjects and Methods Top


The study was carried out at a tertiary care hospital. Consecutive patients coming to the outpatient department who fulfilled the inclusion criteria were included in the study. Eighty subjects of both genders, attending a tertiary care center, were consecutively taken up for the assessment. This sample represents the chronic, stable follow-up patients on maintenance antipsychotic treatment.

Patients from both genders who fulfilled the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, criteria for schizophrenia at the time of assessment, with age between 18 and 60 years, and giving consent were included. All the subtypes of schizophrenia who are cooperative for interview and assessment were included. Patients having any axis-I disorders other than schizophrenia and comorbidities such as diabetes, hypothyroidism, mental retardation, and dementia were excluded. Patients on antidepressants were also excluded.

A semistructured pro forma was administered for all the subjects after getting informed consent. The pro forma contains the demographic profile of the patient, family history, and illness characteristics.

All the subjects were administered the following instruments at the time of recruiting the subjects for this study: Positive and Negative Symptom Scale (PANSS) was used to assess the current level of schizophrenic symptoms, Calgary Depression Scale for Schizophrenia (CDSS) and Hamilton Depression Rating Scale (HDRS) were used to assess the depressive symptoms, Extrapyramidal Symptom Rating Scale (ESRS) was used to measure extrapyramidal symptoms (EPS), Schedule for Assessment of Insight (SAI) was used to assess insight, and Global Assessment of Functioning Scale (GAF) was used to assess the current level of functioning.

Assessment of psychopathological dimension and the depressive symptoms were cross-sectional, indicating the incidence of depressive symptoms at a point in time. Depression was measured based on the rating scales of CDSS and HDRS. Assessment was done by two psychiatrists for better reliability.


  Results Top


Statistical analysis

Descriptive statistics were used to define the sample characteristics. Mann–Whitney U, a nonparametric test, was used to assess the significance of the values obtained in this sample. Chi-square test was employed to find out the sample distribution and cross tables were made. Correlation between different variables was assessed by Pearson's and Spearman's correlation coefficient.

The study group was a homogenous sample consisting of 80 patients. Their sociodemographic and illness variables are given in [Table 1].
Table 1: Sociodemographic profile and illness characteristics of the study group

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Correlation between demographic factors and illness characteristics

The age of the subjects correlated positively with the age of onset and the duration of untreated psychosis (P < 0.05). Education in number of years had a significant negative correlation with the age of onset of the illness (P < 0.01) and HAMD score (P < 0.01). Duration of untreated psychosis had a positive relationship with NSs score of PANSS and GAF score at 0.05 level of significance. This is shown in [Table 2].
Table 2: Pearson's/Spearman's (r) correlation coefficient of demographic variables with disease variables (n=80)

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Psychopathology dimensions of schizophrenia and depression in schizophrenia

[Table 3] shows the mean scores from the rating scales. The mean total PANSS score of the study population is 52.24 (normal baseline value = 30). The mean scores on subscales were as follows:
Table 3: Mean scores of the rating scales

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  • PS (sum of PS score) =15.249 ± 3.033 (range = 7–49)
  • NS (sum of NS score) =11.49 ± 3.819 (range = 7–49)
  • General psychopathology (GP) score = 25.61 ± 4.777 (range = 16–112)


The study group falls under the category of “mild category” in terms of psychopathology. The composite index is −9 to +18 (normal range = 42–42), indicating predominantly PSs.

In this study population, 34.5% had depressive symptoms. This population had a mean Calgary depression rating scale score of 4.46 ± 0.737. In a population of patients with schizophrenia, a score above 6 on CDRS is proposed to separate patients having depression, from those without depression. Earlier study has found optimal cutoff value of at least 7 as “major depression” in patients with schizophrenia and at least 4 to detect “minor depression.” Hence, the current study group qualifies for “minor depression” category.[16]

The mean score on the HAM-D (HDRS) measurement was 9.41 (range = 0–7). A score of 8–13 on HAM-D indicates “mild” in severity of depression. Both the specific Calgary depression rating scale score and the severity scale (HAM-D) clearly depict that the current study group has mild depression associated with schizophrenic psychopathology.

Extrapyramidal symptoms associated with schizophrenic symptomatology

The mean score on extrapyramidal symptom rating scale was below one in all the four subscales, demonstrating that the study populations did not have significant extrapyramidal symptoms during the assessment.

Correlation between psychopathology dimensions of schizophrenia and depression in schizophrenia

The GP score of PANSS had a positive correlation with NS (P < 0.05) and negative correlation with PS (P < 0.01). The GP score correlated positively with CDSS score and HAMD score (P < 0.05). This is shown in [Table 4].
Table 4: Pearson's/Spearman's (r) correlation coefficient of depression scores with mean scores on Positive and Negative Symptom Scale (n=80)

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Functional outcome in depression with schizophrenia

The mean value on GAF scale was 5.90 ± 0.922. A GAF score of >5 indicates moderate function and the degree of functioning goes up above 5. The current study group belongs to “moderate functioning” persons with schizophrenia. This is shown in [Table 5].
Table 5: Pearson's/Spearman's (r) correlation coefficient of mean scores on Calgary Depression Scale for Schizophrenia and Hamilton Depression Rating Scale

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Insight in depression with schizophrenia

The mean score value on SAI was 2.04 ± 2.378. The maximum total score representing the three dimensions of insight is 24. Considering the maximal score on insight which indicates better insight, the study group having the mean value of 2.04 indicates “poor insight.” This is shown in [Table 3].

Correlation between functional outcome, insight, and depression in schizophrenia

The CDSS score and HAMD score had a significant positive correlation with SAI score (P < 0.05). HAMD score had a negative correlation with GAF score (P < 0.05). This is shown in [Table 5].

Mann–Whitney U-test used to assess sample characteristics and Chi-square tests to assess the significance in the family history of schizophrenia, suicide, and mood disorder did not yield any significant results. They are shown in [Table 6] and [Table 7], respectively.
Table 6: Sample characteristics

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Table 7: Chi-square tests

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  Discussion Top


In this study population, 34.5% had depressive symptoms. This is similar to the rate observed in some of the earlier studies.[1] In this investigation, 30% of subjects had major depression (>7 points) based on the CDSS, which is the sensitive measurement separating depression as an integral part of schizophrenia from the secondary factors contributing for depression in schizophrenia. 4.5% of the study subjects had qualified for minor depression, scoring above 4 points in CDSS. The psychopathological aspects of the population revealed that they had a mild level of psychopathology based on the PANSS total score. This represents the stable group of subjects on antipsychotic treatment. Thus, even in this group of patients, we can find a significant number who suffers from depression.

The overlay of depressive symptoms with NSs was variously reported in schizophrenia.[17] The major differentiating symptom was mood, which distinguishes the negative syndrome profile of schizophrenia. In this study, the depressive scores on Calgary Depression Rating Scale for Schizophrenia (CDSS) and HDRS (HAM-D) had shown a statistically significant correlation with GP score of PANSS. The GP score indirectly correlates positively with NSs scale of PANSS. Few authors have reported a positive relationship between depressive symptoms and PSs of schizophrenia. However, in this study, PSs had a negative relationship with GP score, which in turn has a positive correlation with depressive scores on CDSS and HAMD. Thus, we conclude that, in our sample, depressive symptoms are better correlated to GP.

Another area of conceptual confusion has rested on extrapyramidal symptoms due to the apparent resemblance of symptoms and signs. This sample did not have significant extrapyramidal symptoms on the ESRS scale, indicating that there was no drug-induced neurological side effects in the study population. This may be due to the atypical antipsychotic treatment or lower therapeutic maintenance dosage of both conventional and atypical antipsychotic medications.

Depressive symptoms were present while on antipsychotic treatment. The influence of antipsychotics or the role of antipsychotic medications cannot be commented in this sample as no pretreatment assessment was available.

Depressive symptoms in schizophrenia are associated with poor functioning and quality of life scores. Patients with depressive symptoms also need a greater number of hospitalization and high mortality rate including suicide. Bowie et al. observed a negative correlation with functional outcome.[18] Both depressive symptoms and NSs were associated with poor functional outcome.

In the current observation, the duration of untreated psychosis was positively correlated with NSs score of PANSS and GAF score. This represents that delay in the initiation of treatment results in the development of more NSs and more functional impairment, reflecting the functional outcome of the illness. HDRS score had negatively correlated with GAF score. Thus, on par with the available literature, the presence of depressive symptoms predicts an unfavorable outcome of functioning.

The insight score was positively correlated with lower mood in many studies. Poor insight in fact protects against depression.[19]

In analogy with the previous observations, the current observation also reports a statistically positive correlation between CDSS score and HAMD score with the scores on SAI. The degree of insight measured in three dimensions using the SAI scale indicates direct correlation with depression rating scale scores. Patients with schizophrenia are prone to develop depression when they regain their insight during the course of illness.

All the subjects in this study were having mild psychopathology in terms of rating on PANSS, but their mean score on insight was very low, indicating poor insight in the schizophrenia group. The poor insight in the present group may be the reason for lower degree of depressive symptoms leaving them in mild depression category.

Patients on atypical antipsychotic for more than a month have low scores on CDSS scores than patients who have been on typical antipsychotic. This is in agreement with previous studies conducted by various authors who unanimously reported that the second-generation antipsychotics have been associated with reduced symptoms of depression.[20],[21],[22] There may be various probable reasons for this superiority of atypical antipsychotics in the treatment of depressive symptoms in schizophrenia.

One way of looking at it is that, since the atypical antipsychotics do not exert their antipsychotic action exclusively by dopamine blockade, they rely on actions through various other receptors for their therapeutic effect and hence their chances of producing the phenomenon of neuroleptic-induced dysphoria are meager.

It would be inappropriate to conclude from the effect, or lack of effect, found with one agent to apply to other atypical agents. Many molecules in this cluster have precise antidepressant activity in lower doses. In this study, all the subjects receive both typical and atypical antipsychotic drugs in moderate doses. Despite on medications, sample did not have significant extrapyramidal symptoms and had a significant incidence of depression. Based on this observation, we could able to formulate that depression tends to associate with schizophrenia independent of the extrapyramidal symptoms and antipsychotic medications.


  Conclusions Top


This study demonstrates that patients with schizophrenia have significant depressive symptoms, which appear to be independent of extrapyramidal symptoms and correlates positively to schizophrenic psychopathology. Poor insight may have led to low severity of reported depressive symptoms. Furthermore, the presence of depression may lead to poor levels of functioning.

Limitations

Our study is a hospital-based study which is not a genuine epidemiological sample. This also increases the so–called Berksonian bias – the more conditions a patient suffers from, the higher the likelihood of seeking treatment – which leads to an overrepresentation of patients with multiple diagnosis in samples recruited from clinical settings. Patients with PSs are more likely to come to the hospital and hence the sample contains more patients with PS.

Ethical statement

This study was approved by Institutional Ethics Committee with reference number IEC/MMC/12082011 obtained on 16th August, 2011.

Declaration of patient consent

Patient consent statement was taken from each patient as perinstitutional ethics committee approval along with consenttaken for participation in the study and publication of thescientific results / clinical information /image withoutrevealing their identity, name or initials. The patient is awarethat though confidentiality would be maintained anonymitycannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]



 

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