Social cognition in siblings of patients with bipolar disorders.

BACKGROUND: Identifying people at risk of developing bipolar disorder (BD) using endophenotypes is of recent interest. Few studies on social cognition in first-degree relatives of patients with BD have shown inconsistent findings. This study aimed to evaluate the social cognitive deficits (SCD) and its correlates among siblings of patients with BD.
METHODOLOGY: In this cross-sectional study, patients of BD (n = 32), their siblings (n = 32), and healthy control (HC) subjects (n = 38) matched for age, gender, and education were evaluated on social cognition rating tools in Indian setting and neurocognitive tests (color trail test, Wisconsin card sorting test [WCST], and Hopkin's verbal learning test [HVLT]).
RESULTS: When the siblings of patients with BD were compared with patients with BD and the HCs, siblings (mean 0.6 [standard deviation [SD]: 0.2]) performed worse than the HCs (mean 0.9 [SD: 0.1]) (P ≤ 0.001) on the Faux pas composite index. Compared to HCs, siblings performed worse on all the subtests of HVLT (Trial delayed) (P < 0.001) and WCST (total correct, total errors, and conceptual responses) (P < 0.001).
CONCLUSION: Presence of elevated level of SCD among siblings, especially the Faux pas composite index in comparison to HCs, imply that these are stable traits, which are more often present in the patients and at risk individuals. This implies that SCD can be considered as another important endophenotype for BD. Copyright:

Identifying people at risk of developing bipolar disorder (BD) is of recent interest. One of the ways of identifying people at risk is by identifying different endophenotypes, which are understood as heritable susceptibility factors which are not noticeable to the unaided eye, are present in both symptomatic/asymptomatic phase of illness and in unaffected relatives.[123] These are present in individual even when the patient does not have active illness (state independent factors) and they co-segregate within families with illness. The endophenotypes for BD include abnormal regulation of circadian rhythms, response to sleep deprivation, P300 event-related potentials, behavioral responses to psychostimulants and other medications, higher prevalence of white matter hyperintensities in the neuroimaging, biochemical observations in peripheral mononuclear cells and neurocognitive deficits, etc.[4]

Few studies have evaluated social cognition (SC) amongst patients with BD and a very few have evaluated in high-risk groups such as first-degree relatives (FDR) of these patients.

Among the various endophenotypes for BD, neurocognitive deficits have been evaluated extensively.[567] In recent times, social cognitive deficits (SCD) have also been evaluated for possible endophenotypes, although when compared with neurocognitive deficits, research on SCs in BD is still sparse. SC is a multidimensional psychological domain that involves a set of processes that enable adaptive social interaction. The adaptive social interaction includes representation of internal somatic states, understanding about the self, perception of others, and interpersonal motivations.[3] Few studies have evaluated SC amongst patients with BD and a very few have evaluated in high-risk groups such as FDR of these patients.

The studies which have evaluated SC in FDR of patients with BD have been inconsistent. In general these studies have included 20–30 participants, with only one multicentric study, including 200 subjects.[891011121314] The studies have mainly focused on theory of mind (ToM), emotional recognition, and decision-making tasks. Finding in these studies are inconsistent as some of these studies suggest that FDR have impaired facial emotion recognition and ToM, when compared to healthy controls (HCs).[891011] But others report lack of significant difference between HC and FDR of patients with BD.[121314]

Keeping these facts in consideration, the current study aimed to assess the SC deficits in the siblings of patients with BD and compared the same with their ill relatives and a HC group.

METHODOLOGY

This cross sectional study was conducted in a tertiary care institute in north India, after due approval from the Ethics Committee of Institute. A written informed consent/assent was taken from all the participants. The sample collection was done from February 2017 to December 2017 using purposive sampling. The sample comprised of 3 groups: 32 siblings of patients with BD constituted Group-I, 32 corresponding patients with BD constituted Group-II (whose siblings formed the Group-I) and 38 HCs formed the Group-III. Study participants (in all the 3 groups) for inclusion in the study were required to be aged 16–35 years and be able to comprehend Hindi and English. If the participant was aged between 16 and 18 years, then additional consent of one of the parents was also obtained. Additionally, for inclusion of the participants in the sibling group, the participants were required to have a sibling with the diagnosis of BD but themselves not been diagnosed with any diagnosable mental disorder as ascertained by using MINI-screen[15] by clinician. Participants in the BD group (Group-II) were required to be diagnosed with BD type 1 as per MINI-PLUS[16] and currently in clinical remission by clinician. Remission in the current study was defined as scores of ≤7 on Hamilton's depression rating scale and Young's mania rating scale. For HC group (Group-III), participants were required to be free from any mental disorder as assessed by using MINI-screen and none of their FDRs had a history of any major mental disorders. We excluded persons with intellectual disability, organic brain syndrome, chronic medical disorder (like organic-epilepsy or any neurological illness), any current/past history of substance use disorder (other than tobacco), and presence of medically diagnosable and/or self-reported visual and/or auditory impairment (not correctable with Aids) from the Group-II. The 3 study groups were age, gender, and education matched.

The study instruments included

First the sociodemographic profile of the participants was completed. Clinical profile sheet was completed for the patient group. Participants in the sibling group and HC were assessed on MINI-Screen. Then, all the participants were assessed on social cognition rating tools in Indian setting (SOCRATIS) and Neurocognitive battery.

Social cognition rating tools in Indian setting[17]

It assesses (1) ToM, (2) Attributional styles, and (3) social perception. SOCRATIS was developed to assess SC in Indian culture background. SOCRATIS has good content validity (>4 score by >75% of experts) and known group validity.

Neurocognitive tests

Three neurocognitive tests were used in this study: color trail test (CTT),[18] Wisconsin card sorting test (WCST),[19] and Hopkin's verbal learning test (HVLT).[20]

Statistical analysis

Descriptive analysis was carried out for continuous variables using mean and standard deviation and for categorical and ordinal variables as frequency and percentages. ANOVA, t-test, Mann–Whitney U test, Chi-square test, and Fisher's exact test were utilized for comparison between the groups. Pearson's product moment correlation and Spearman's rank correlation were used to assess the association between the SC and other variables.

RESULTS

Selection of the sample

During the study period from February 2017 to December 2017, 43 patients of BD with their siblings meeting the selection criteria were approached. Out of the 43, 7 patients of BD did not consent for assessment, 2 withdrew consent due to personal reasons and two patients had exacerbations of the illness prior to the appointment given for assessments. Thus, the study sample consists of 32 patients with BD and their siblings.

Socio demographic profile

The mean age of study groups was 26.3 (4.4) years and the mean duration of education was 13.2 (3.3) years. The 3 groups did not differ statistically on the demographic variables, except for the fact that compared to the HC and siblings, higher proportion of the patients were single [Table 1].

Table 1

Comparison of Sociodemographic details of patients with bipolar disorder, siblings of patients with bipolar disorder and healthy control group

Variables	Mean (SD)/frequency (%)			ANOVA test/Chi-square test (P)
	Patient (n=32)	Sibling (n=32)	Healthy control (n=38)
Age (years)	26.3 (4.4)	27.5 (4.7)	25.3 (4.7)	F=1.922 (0.152)
Education (years)	13.2 (3.3)	13.7 (3.2)	14.5 (2)	F=1.988 (0.142)
Sex
Male	24 (75)	20 (62.5)	20 (52.63)	χ2=3.719 (.156)
Female	8 (25)	12 (37.5)	18 (47.37)
Marital status
Currently single	23 (71.9)	14 (43.8)	28 (73.7)	χ2=8.073 (0.018)*
Currently married	9 (28.1)	18 (56.3)	10 (26.3)
Education (years)
≤12th	16 (50.0)	14 (43.7)	10 (26.3)	χ2=4.490 (0.106)
>12th	16 (50.0)	18 (56.3)	28 (73.7)
Occupation status
Unemployed	15 (46.9)	12 (37.5)	16 (42.1)	χ2=0.577 (0.749)
Employed	17 (53.1)	20 (62.5)	22 (57.9)
Socioeconomic status
Lower middle and below	18 (56.3)	12 (37.5)	12 (31.6)	χ2=4.625 (0.099)
Upper middle and above	14 (43.8)	20 (62.5)	26 (68.4)
Religion
Hindu	23 (71.9)	22 (68.8)	32 (84.2)	χ2=2.574 (0.276)
Non-Hindu	9 (28.1)	10 (31.2)	6 (15.8)
Type of family
Nuclear	17 (53.1)	14 (43.8)	25 (65.8)	χ2=3.467 (0.177)
Extended/Joint	15 (46.9)	18 (56.3)	13 (34.2)
Locality
Urban	19 (59.4)	22 (68.7)	25 (65.8)	χ2=0.647 (0.724)
Rural	13 (40.6)	10 (31.3)	13 (34.2)

*P≤0.05. SD – Standard deviation

Clinical profile of patients with bipolar disorder

Clinical profile of patients with BD is shown in Table 2.

Table 2

Clinical profile of patient with bipolar disorder (n=32)

Variables	Mean (SD)/frequency (%)
Age of onset (years)	20.3 (3.9)
Duration of illness (months)	70.2 (50.5)
Duration of treatment (months)	62.3 (52.2)
Duration of current remission (months)	17 (18.2)
Total time spent in the episodes in lifetime (months)	6.8 (4.2)
Total number of episodes in a lifetime	2.9 (1.3)
Most recent episode
Depression	11 (34.4)
Mania	19 (59.4)
Hypomania	2 (6.2)
Total number of manic episodes in lifetime	2 (1)
Total number of mixed episodes	0
Total number of hypomanic episodes	0.1 (0.4)
Total number of depressive episodes in lifetime	1 (1.2)
Total number of manic episodes with psychotic symptoms	0.5 (0.7)
Total number of depressive episodes with psychotic symptoms	0.2 (0.4)
Presence of at least one episode with psychotic symptoms (yes)	17 (53.1)
Average mean duration of manic episodes (months)	3.5 (3.5)
Average mean duration of depressive episodes (months)	3.3 (3.7)
Mean of severity of depressive episodesa	1.3 (1.2)
Affective morbidity indexb	2.9 (2.9)
Number of lifetime suicidal attempts	0.1 (0.3)
Lifetime suicidal ideations (yes)	14 (43.8)
Lifetime suicidal attempts (yes)	3 (9.4)
Young Mania Rating Scale total score	0.4 (0.9)
Hamilton Depression Rating Scale total score	2.8 (0.8)
Number of patients with comorbid physical illness (yes)	5 (15.6)
Co-morbid physical illness
Hypothyroidism	3 (9.4)
Hypertension	2 (6.3)
Diabetes mellitus	1 (3.1)
Family history of psychiatric illness (yes)	14 (43.7)
Family history
Psychotic illness	4 (12.5)
Affective	10 (31.3)
Comorbid substance dependence
Tobacco dependence	5 (15.6)
Rapid cycling affective disorder (no)	32 (100)
Seasonal affective disorder (yes)	3 (9.4)
Pattern of illness
DMI	14 (43.8)
MDI	18 (56.2)

aSeverity of affective episodes was rated on a 4 point scale: 0- no episode; 1-Mild; 2-Moderate; 3-Severe, bAffective morbidity index was calculated by multiplying the number of episodes with severity of episodes and duration of episodes in years. DMI – Depression-mania-interepisodic period; MDI – Mania-depression-interepisodic period; SD – Standard deviation

Comparison of social and neurocognitive deficits in three groups

Comparison of siblings of patients with BD, with patients with BD and the HC, shows that the siblings performed poorly than the HC on the Faux pas composite index. Patients with BD performed worse when compared to HC on the Faux pas composite index and nonsocial perception index. Performance of patients with BD was inferior to the siblings on nonsocial perception index. Patients with BD also performed below par than the siblings and HC on the HVLT, CTT and WCST. Though, in some of the subtests of HVLT (trial delayed) and WCST (total correct, total errors, and conceptual responses), there was a noteworthy difference between the siblings and the HC [Table 3].

Table 3

Comparison of social cognitive and neurocognitive deficits of patients with bipolar disorder, siblings of patients with bipolar disorder and healthy control groups

Variables	Mean (SD)/frequency (%)			ANOVA test/Chi-square test (P)	Post hoc Bonferroni corrections (only significant group differences shown)
	Patient (n=32)	Sibling (n=32)	Healthy control (n=32)
Social cognition
First order theory of mind index	0.9 (0.1)	1 (0.1)	1 (0)	2.684 (0.073)	No significant group differences
Second order theory of mind index	0.6 (0.3)	0.7 (0.3)	0.9 (0.2)	2.623 (0.078)	No significant group differences
Faux pas composite index	0.7 (0.2)	0.6 (0.2)	0.9 (0.1)	28.331 (<0.001)***	I>II; I<III***; II<III***
Social perception index	0.7 (0.1)	0.9 (0.1)	0.8 (0.2)	0.940 (0.394)	No significant group differences
Nonsocial perception index	0.8 (0.1)	0.9 (0)	0.9 (0.1)	8.354 (<0.001)***	I<II***; I<III**; II=III
Externalizing bias index	4.3 (4.9)	4 (4.9)	3.2 (4.5)	0.212 (0.810)	No significant group differences
Personalizing bias index	0.7 (0.3)	0.7 (0.2)	0.6 (0.2)	1.206 (0.304)	No significant group differences
Neurocognition
Hopkin’s verbal learning test
Trial 1	5.6 (1.4)	6.8 (1.3)	6.9 (2)	7.409 (0.001)**	I<II**; I<III**
Trial 2	7.3 (1.6)	8.7 (1.5)	9.1 (1.9)	9.036 (<0.001)***	I<II**; I<III***
Trial 3	8.3 (1.5)	9.6 (1.3)	10.3 (1.9)	12.715 (<0.001)***	I<II**; I<III***
Trial delayed	5.1 (1.6)	6.9 (1.9)	9.2 (1.7)	31.486 (<0.001)***	I<II***; I<III***; II<III***
Retention score	0.6 (0.17)	0.7 (0.17)	0.9 (0.14)	24.741 (<0.001)***	I<II***; I<III***; II<III***
Recognition discrimination index	20.9 (4.0)	24.8 (3.2)	25.2 (4.7)	11.250 (<0.001)***	I<II***; I<III***
Color trail test
Test 1 (time in s)	52.7 (25.3)	44 (16.1)	36.3 (13.2)	6.552 (0.002)**	I>III***
Test 2 (time in s)	134.4 (47.4)	103.2 (38.5)	87.9 (23.3)	14.254 (<0.001)***	I>II**; I>III***
Test 1 error	0	0	0 (0.2)	1.725 (0.183)	No significant group differences
Test 2 error	0.5 (0.8)	0.4 (0.6)	0.6 (1)	0.723 (0.488)	No significant group differences
Wisconsin card sorting test
Total correct	32.4 (10.6)	38.8 (9.9)	46.2 (5.1)	23.088 (<0.001)***	I<II*; I<III***; II<III***
Total errors	31.6 (10.6)	25.2 (9.9)	17.8 (5.1)	23.088 (<0.001)***	I>II*; I>III***; II>III***
Perseveratory responses	15.7 (9.9)	15.3 (10)	9.7 (4.6)	6.049 (0.003)**	I>III**; II>III*
Persveratory errors	13.6 (7.5)	12.8 (7.3)	8.5 (3.5)	7.380 (0.001)***	I>III**; II>III*
Nonperseveratory errors	17.9 (10.4)	12.4 (7.7)	9.3 (3.5)	11.914 (<0.001)***	I>II*; I>III***; II>III
Conceptual responses	23.1 (13.6)	30.5 (14.1)	41.4 (7.2)	22.143 (<0.001)***	I<II*; I<III***; II<III***

*P≤0.05; **P≤0.01; ***P≤0.001; F – ANOVA value. χ2 – Chi-square value; T – t-test; SD – Standard deviation

Correlation between social and neurocognition among siblings of patients with bipolar disorder

Among the siblings, there were significant correlations of SC in the domains of second order ToM and Faux pas composite index with verbal learning test. Scores on second order of ToM also had significant correlations with CTT. Social perception index had correlation with total correct responses, total errors, and conceptual responses on WCST. Nonsocial perception index, externalizing bias, and personalized bias index had no significant correlations with any of the neurocognitive deficits [Table 4].

Table 4

Correlation between social and neurocognition among siblings of patients with bipolar disorder

Variables	First order theory of mind index	Second order theory of mind index	Faux pas composite index	Social perception index	Nonsocial perception index	Externalizing bias index	Personalizing bias index
Hopkin’s verbal learning test
Trial 1	0.044 (0.812)	0.538 (0.002)**	0.195 (0.286)	0.179 (0.328)	0.149 (0.417)	0.081 (0.659)	−0.065 (0.724)
Trial 2	0.144 (0.433)	0.49 (0.004)**	0.41 (0.02)*	0.138 (0.451)	0.093 (0.613)	−0.021 (0.911)	−0.271 (0.133)
Trial 3	0.145 (0.429)	0.268 (0.139)	0.148 (0.419)	−0.114 (0.535)	−0.042 (0.821)	0.144 (0.433)	−0.128 (0.486)
Trial delayed	0.391 (0.027)*	0.155 (0.397)	0.35 (0.05)*	0.142 (0.437)	0.035 (0.848)	0.032 (0.861)	−0.33 (0.065)
Retention score	0.376 (0.034)*	0.055 (0.764)	0.380 (0.032)*	0.292 (0.105)	0.077 (0.674)	−0.53 (0.773)	−0.271 (0.133)
Recognition discrimination index	0.154 (0.401)	0.549 (0.001)**	0.348 (0.051)	0.084 (0.648)	0.048 (0.793)	0.083 (0.653)	−0.216 (0.235)
Color trail test
Test 1 (time in s)	−0.048 (0.794)	−0.419 (0.017)*	−0.317 (0.077)	−0.241 (0.184)	−0.144 (0.432)	0.01 (0.955)	0.152 (0.407)
Test 2 (time in s)	−0.312 (0.082)	−0.434 (0.013)*	−0.312 (0.082)	−0.29 (0.108)	0.017 (0.926)	−0.054 (0.771)	0.074 (0.687)
Test 2 error	0.022 (0.903)	0.083 (0.652)	0.269 (0.137)	−0.109 (0.552)	−0.153 (0.404)	−0.015 (0.935)	0.12 (0.513)
Wisconsin card sorting test
Total correct	−0.284 (0.116)	0.238 (0.19)	0.01 (0.956)	0.366 (0.039)*	0.126 (0.491)	−0.093 (0.611)	−0.166 (0.365)
Total errors	0.284 (0.116)	−0.238 (0.19)	−0.01 (0.956)	−0.366 (0.039)*	−0.126 (0.491)	0.093 (0.611)	0.166 (0.365)
Perseveratory responses	0.106 (0.563)	−0.296 (0.1)	0.057 (0.756)	−0.205 (0.261)	−0.114 (0.534)	0.262 (0.148)	−0.056 (0.759)
Persveratory errors	0.124 (0.5)	−0.281 (0.119)	0.082 (0.655)	−0.225 (0.217)	−0.125 (0.496)	0.257 (0.156)	−0.065 (0.724)
Nonperseveratory errors	0.246 (0.175)	−0.036 (0.844)	−0.092 (0.618)	−0.256 (0.158)	−0.043 (0.816)	−0.126 (0.492)	0.275 (0.127)
Conceptual responses	−0.266 (0.141)	0.247 (0.172)	−0.006 (0.974)	0.359 (0.044)*	0.101 (0.583)	−0.043 (0.817)	−0.202 (0.268)

*P≤0.05; **P≤0.01

DISCUSSION

BD is considered as a polygenic disorder, and endophenotypes are used to identify people at risk. In recent times, efforts have been made to consider SC deficits as endophenotypes for BD. However, the issue is not yet settled because of contradictory findings. Therefore, in the current study, an attempt was made to evaluate the SC deficits in the siblings of patients with BD and compare the same with their ill relatives and a HC group.

No significant difference was seen in the demographic profile of siblings and the HC groups, except that majority of HC subjects were single. Accordingly, it can be said that any noteworthy difference in the SC between the siblings of patients with BD and HC cannot be attributed to the demographic variables.

Available evidence suggest that although there is lack of consensus across different studies, there is a general trend, which suggests that the SCD in patients with BD are greater than FDR which are in turn greater than HC.[891011] In the current study too, patients with BD performed the worse, and the HC performed the best on most of the SC tasks, with siblings falling midway between the two groups on all the subtests of SC except for faux pas composite index and externalizing bias where siblings performed worse than the patient group. The presence of an elevated level of SC deficits among siblings in comparison to HC suggests that these are stable traits, which are more frequently present in the patients and at-risk individuals. This suggests that SC deficits can be considered as another significant endophenotype for BD.

Findings of the present study suggest that compared to HC, patients with BD have significantly higher deficit in the Faux pas composite index and nonsocial perception index. Further when compared with siblings, patients with BD have higher deficits in the social perception index and nonsocial perception index. Siblings and HC differed significantly in the domain of faux pas composite index. These findings suggest that faux pas composite index, which indicates deficits in ToM may possibly be a social cognitive endophenotype for BD, which is present in both patients with BD and siblings, with higher level of deficits among patients.

Previous studies on SC deficits in patients with BD and their FDR have mainly focused on ToM, emotional recognition, and decision-making.[891011121314] In our study, only ToM was evaluated. There is lack of consensus concerning the deficits in ToM in patients with BD in the euthymic phase, with some of the studies suggesting compared to HC, patients with BD have deficits in the first and second order ToM task,[212223] faux pas index,[24] whereas others suggest lack of difference between patients with BD in euthymic phase and HC.[2526] The study findings support the second group of studies with respect to first and second-order ToM task, whereas it supports the first set of studies with regard to faux pas index.[24]

In terms of comparison of patients with BD and FDR, some of the studies have reported significant difference between patients and FDR with respect to ToM tasks[9] including faux pas.[11] However, present study, does not support these findings and suggest that ToM and faux pas index functioning is similar in patients and siblings. Considering that faux pas index differed significantly between patients and HC and also between siblings and HC, but not between the patients and siblings, this can be considered as an endophenotype of BD for further research.

Social perception index and nonsocial perception index as assessed in the present study is considered as a larger domain of cognitive skills which includes ToM, emotion recognition, understanding body language and social attention, all of which deals with organizing information which culminates in the exact perception of dispositions and intentions of other individuals.[27] If this domain is taken as a proxy measure of emotional recognition, the finding of the present study suggests that compared to HC patients with BD have deficits in emotional recognition. Some of the previous studies, which have compared patients with BD and HC, also suggest that patients with BD have deficits in the emotional recognition.[282930] However, other studies have reported lack of difference between the two groups.[242631323334] Findings of the present study support the studies which have reported difference between patients with BD and HC. However, this finding must be interpreted in the light of the fact that, in the present study, no specific facial emotional recognition task was used. Accordingly, it can be said that this issue is not yet settled and there is a need to carry out further studies to reach to a consensus.

Overall, present study findings reveal that patients with BD and siblings of BD differ significantly from HC on faux pas task, whereas patients with BD differ from HC and siblings on the emotional recognition tasks. Accordingly, it can be said that these 2 tasks must be considered while evaluating persons at risk of BD and those found to have deficits in faux pas index need to be considered at risk of developing BD, and those found to have deficits in faux pas index need to be considered at risk of developing BD. Further, the early intervention programs focusing on high risk and ultra-high-risk groups must include interventions to address these SCD.

Neurocognitive assessment in the present study included tests for assessment of attention, verbal learning, and executive functions. As expected, patients with BD performed worse on the verbal learning test among all the groups. There was, however a significant difference between the siblings and the HC only in some of the subtests of verbal learning test and executive functioning. Patients with BD and siblings differed significantly only on some of the subtests executive functions and attention. Findings of the present study are supported by the data from across the globe which suggest that compared to HC, patients with BD have neurocognitive deficits in the domain of attention, verbal learning, and executive functions.[5635] Additionally, the presence of significant verbal learning deficits and executive function deficits among patients with BD and their sibling implies that these may be better endophenotypes when compared to other neurocognitive functions.

In the present study, no significant associations emerged between demographic variables and SC in siblings of patients with BD, except for difference on externalizing bias index between those from a different locality, higher deficits in second-order ToM index among those from extended/joint family when compared with those from nuclear families and a higher level of second-order ToM deficits with increasing age. Previous studies have not looked at these associations; hence, we could not compare these findings with the existing literature. Future studies must attempt to replicate these findings in a larger sample size to reach any definite conclusion. When the association of social and neurocognition was evaluated among the siblings of patients with BD, significant positive correlations were seen between the SC domains of first-order ToM, second order ToM and Faux pas composite index with verbal learning test. Scores on CTT correlated negatively with second order ToM task and executive function test scores had noteworthy positive correlation with social perception index.

Externalized and personalized bias index, in general, had no significant correlations with any of the neurocognitive deficits. Review of literature among FDR of patients with BD did not reveal any existing data on the issue to compare the findings of the current study with the existing literature. Hence, the results of the present study may be considered as preliminary. Data on patients with schizophrenia and their FDR suggest mixed findings, with some of the studies showing no association, whereas others suggest that cognitive abnormalities and intelligence quotient could explain the SC deficits observed in FDR of patients with schizophrenia.[36373839] Accordingly, it can be said that the same may also be true for siblings of patients with BD. However, there is a need to replicate the findings of the present study, to draw any firm conclusions.

CONCLUSION

To conclude current study suggests that patients with BD perform the worst and the HC perform the best on most of the SC tasks, with siblings falling intermediate between the patients and HC on all the subtests of SC except for faux pas composite index and externalizing bias where siblings performed worse than patient group. Among the various domains of SC, faux pas index, indicative of deficits in ToM, can possibly be considered and studied further as a candidate endophenotype for BD. However, these findings need to be replicated with larger sample size, normality test for task performances, and evaluation of biomarkers to conclude these findings with confidence. Among patients with BD, in general, SC is not associated with demographic and clinical variables. However, SC has significant association with neurocognition among patients as well as siblings of patients with BD.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.