Research report
I can see what you feel, but I can't deal with it: Impaired theory of mind in depression

https://doi.org/10.1016/j.jad.2011.02.010Get rights and content

Abstract

Background

Even though unipolar depression is associated with considerably impaired social functioning, only a few studies so far have investigated Theory of Mind (ToM) abilities of unipolar depressed patients. Therefore, the main goal of this study is to examine whether depressed patients are impaired in their ToM as compared to healthy controls. Thereby, both aspects of ToM, i.e. decoding and reasoning, are examined separately.

Methods

Acutely depressed patients with unipolar affective disorder (n = 24) and healthy controls (n = 20) were examined with the ‘Reading the Mind in the Eyes Test’ (RMET) and the ‘Movie for the Assessment of Social Cognition’ (MASC) to address the two aspects of ToM.

Results

Patients compared to controls did not show impaired decoding ability in the RMET, but did show deficits in integrating contextual information about other people (reasoning) in the MASC. This impairment is independent of the mental state modality that had to be judged (emotional vs. cognitive).

Limitations

Possible differences between the diagnostic subgroups of depression, which play an important role in clarifying the opposing results concerning the association between ToM abilities and depression in the existing literature, have not been examined.

Conclusions

It is possible that the low level of social functioning associated with depression can be ascribed partially to a ToM deficit and should be addressed in the treatment of depression.

Introduction

Individuals suffering from affective disorders exhibit maladaptive behaviours which can affect the relationship with others and lead to negative social interactions (Joiner, 2002 for review). This, in turn, can precede and increase depressive symptoms (Johnson et al., 2000, Joiner, 2002). One concept used to understand impaired social functioning is the ‘theory of mind’ (ToM) (Baron-Cohen, 1989, Bora et al., 2006). ToM is defined as the ability to understand and predict the social behaviour of others by ascribing mental states to them (Baron-Cohen et al., 1999, Frith and Frith, 2006). This concept has been treated repeatedly as a unitary process, but recently attempts have been made to split ToM into two separate aspects, requiring the involvement of perceptual and conceptual processes (Tager-Flusberg & Sullivan, 2000): (1) decoding of mental states from observable social information (e.g., facial expression) which requires more basic processes, and (2) reasoning about mental states by integrating contextual information about a person (e.g., knowledge) involving rather higher order functions. This distinction is supported by neuroimaging and lesion data, suggesting different networks to be involved in ToM decoding and ToM reasoning processes (Tager-Flusberg and Sullivan, 2000, Siegal and Varley, 2002, Russel and Sharma, 2003, Sabbagh et al., 2004).

To date, impaired ToM abilities have been described in a variety of psychiatric disorders that are associated with social deficits — especially in autistic spectrum disorders (Baron-Cohen, 1995), and schizophrenia (Brüne, 2005), but up to now surprisingly few studies investigated ToM skills in depressed patients. Looking at the decoding ability of depressed patients, there is some evidence to suggest that depressed individuals are impaired in matching facial emotional expressions and exhibit a recall bias for negative social stimuli (Rubinow and Post, 1992, Ashtana et al., 1998, Ridout et al., 2003, Jermann et al., 2008). However, ToM decoding is more specific and more complex than that. It refers to the ability to detect complex mental states that are depicted in different social stimuli.

Lee et al. (2005) used the Reading the Mind in the Eyes Task (RMET, Baron-Cohen et al., 2001) and compared the decoding ability of mildly/moderately depressed women, severely depressed women, and nondepressed women. They found that both depressed groups were less accurate in the RMET than the control group, with a significant difference between the severely depressed women and healthy controls. Wang et al. (2008), who also used the RMET, found that severely depressed patients are impaired in their decoding ability as compared to healthy controls. In contrast to these studies, other studies did not find decoding deficits in people suffering from depression: For example, Kettle et al. (2008) also examined the ToM ability measured by the RMET of patients with non psychotic major depression. In this study the depression group was significantly impaired as compared to a university control group, but not when compared to a community control group. Furthermore, the groups differed in their level of education, which means, that less participants in the depression group have ever attended tertiary education but more in the university control group. Kettle et al. (2008) suggest that “using community control groups may help minimise false positive conclusions about theory of mind deficits in psychiatric populations” (p. 100). A second look at the study conducted by Lee et al. (2005) reveals that there the nondepressed group has also had a significantly higher education than the severely depressed group. Wang et al. (2008) controlled for the educational level of the samples they included and still found a significant difference in the RMET between depressed patients and healthy controls. However, in contrast to Kettle et al. (2008), Wang et al. (2008) only assessed the number of years of education and did not assess whether participants ever attended tertiary education.

While there are several studies examining the second aspect of ToM (reasoning) in patients with bipolar affective disorders (Kerr et al., 2003, Olley et al., 2005) only few studies have been conducted including subjects with unipolar affective disorders. Two studies that did so revealed contradictory findings (Doody et al., 1998, Inoue et al., 2004), but these findings are difficult to interpret as both of these studies did not examine unipolar and bipolar patients separately. To our knowledge, only two studies investigated reasoning deficits exclusively in unipolar depression: Uekermann et al. (2008) examined humor and mentalizing in depression. They read joke stems and presented alternative endings afterwards. They found that depressed patients show impairments in cognitive and affective components of humor processing. Furthermore, they asked ”mentalistic questions“, which referred to the perspective of the protagonists of the jokes. Depressed patients performed significantly worse than the control group in the mentalistic questions. Reasoning ability in depression was also examined in a study by Wilbertz et al. (2010) who focused on early onset chronic depression and assessed the reasoning ability by means of Movie for the Assessment of Social Cognition (MASC, Dziobek et al., 2006), an evaluated mindreading tool that involves the presentation of a short film and the administration of questions referring to the actors' mental states. In contrast to Uekermann et al. (2008), Wilbertz et al. (2010) did not find reasoning impairments in individuals with depression. This may be due to the different ToM tasks that were used in the studies or to the more restricted sample of chronic depressed subjects in the Wilbertz et al. (2010) study. Furthermore, Wilbertz et al. (2010) did not control for possible psychopathology in their healthy control group, which might have led to the non-significant finding. Therefore, the second goal of our study was to examine the reasoning ability of unipolar depressed patients (not specifically chronic depression) by using the MASC. We decided to use this measure because of its very high ecological validity.

Summarizing the available knowledge related to social cognitive functioning in unipolar depression leads to inconclusive and contradictory findings. Two studies show that individuals suffering from depression are impaired in their decoding ability (Lee et al., 2005, Wang et al., 2008) while another study could not replicate this finding (Kettle et al., 2008). It is an open question whether the results indicating decoding deficits in depression are false positive findings due to inappropriate control groups. Furthermore, it is possible that such deficits are only associated with severe forms of depression but not with more moderate forms. In addition, the only two studies that examined the reasoning abilities of depressed patients also lead to contradictory results (Uekermann et al., 2008, Wilbertz et al., 2010). Therefore, the goal of our study is to examine the decoding and reasoning aspects of ToM in patients suffering from acute unipolar depression by using an appropriate control group matched to the clinical group by possible confounding variables.

Section snippets

Participants

Twenty-four patients with depressive disorders were recruited through our outpatient clinic. Patients were compared to 20 healthy subjects matched for age, gender, and level of education (Table 1).

A trained clinician diagnosed patients using the Structured Clinical Interview for DSM-IV (SCID-I). At the time of participation, all patients met the criteria for acute major depressive disorder as assessed by the SCID-I. Patients were excluded if they met criteria (current or lifetime) for a

Reading the Mind in the Eyes (RMET)

To determine whether there are group differences concerning the accuracy in the RMET we conducted a two-way, 3 × 2 mixed factor ANOVA (valence [negative, positive, neutral]  × group [depressed patients, healthy subjects]).

The ANOVA revealed a significant effect of valence, F(2,84) = 9.54, p < 0.001, η2 = 0.19, indicating that the accuracy rate of all subjects varied depending on the valence of the RMET stimuli. The post-hoc analyses revealed that subjects responded more accurately to stimuli of a

Discussion

The main goal of this study was to examine the two aspects of ToM — decoding and reasoning — in unipolar depressed patients compared to healthy controls.

Firstly, we did not find a decreased decoding ability in depressed patients as compared to healthy controls when looking at the total RMET score. However, we did find an interaction between ‘group’ and ‘valence’, which indicates that the accuracy rate between the two experimental groups differed depending on the valence of the mental state.

Role of funding source

There was no funding source.

Conflict of interest

All authors declare that they have no conflict of interest.

Acknowledgements

We thank Aiste Jusyte and Ryan Dutton who assisted with the proof-reading of the manuscript.

References (41)

  • D.R. Rubinow et al.

    Impaired recognition of affect in facial expression in depressed patients

    Biol. Psychiatry

    (1992)
  • A.J. Rush et al.

    The 16-item Quick Inventory of Depressive Symptomatology (QIDS), clinician rating (QIDS-C), and self-report (QIDS-SR): a psychometric evaluation in patients with chronic major depression

    Biol. Psychiatry

    (2003)
  • Y. Wang et al.

    Theory of mind disability in major depression with or without psychotic symptoms: a componential view

    Psychiatry Res.

    (2008)
  • G. Wilbertz et al.

    Exploring preoperational features in chronic depression

    J. Affect. Disord.

    (2010)
  • H.S. Ashtana et al.

    Visuospatial and affect recognition deficit in depression

    J. Affect. Disord.

    (1998)
  • S. Baron-Cohen

    The autistic child's theory of mind: a case of specific developmental delay

    J. Child Psychol. Psychiatry

    (1989)
  • S. Baron-Cohen

    Mindblindness: an Essay on Autism and Theory of Mind

    (1995)
  • S. Baron-Cohen et al.

    Social intelligence in the normal and autistic brain: an fMRI study

    Eur. J. Neurosci.

    (1999)
  • S. Baron-Cohen et al.

    The “Reading the Mind in the Eyes” test revised version: a study with normal adults, and adults with Asperger syndrome or high-functioning autism

    J. Child Psychol. Psychiatry

    (2001)
  • A.L. Bouhuys et al.

    Depressed patients' perceptions of facial emotions in depressed and remitted states are associated with relapse: a longitudinal study

    J. Nerv. Ment. Dis.

    (1999)
  • Cited by (151)

    View all citing articles on Scopus
    View full text