Autistic traits in the general population: What mediates the link with depressive and anxious symptomatology?

Research in Autism Spectrum Disorders 4 (2010) 415–424

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Autistic traits in the general population: What mediates the link with depressive and anxious symptomatology? Ainslie Rosbrook, Koa Whittingham * School of Psychology, University of Queensland, Brisbane, Australia

A R T I C L E I N F O

A B S T R A C T

Article history: Received 5 October 2009 Received in revised form 19 October 2009 Accepted 22 October 2009

The high prevalence of anxiety disorders and depression within the autism spectrum disorder (ASD) population is widely recognised. This study examined the role of three potential mediating variables in the relationship between autistic traits and depressive/ anxious symptomatology in the general population. Participants included 231 university students (114 males, 117 females) ranging in age from 17 to 35 (M = 18.9, SD = 2.77). Participants completed five standardised questionnaires which measured: autistic traits, depressive/anxious symptomatology, social competence, social problem-solving ability, and teasing history. Two multiple mediation analyses were conducted using the bootstrapping method. Results revealed that social problem-solving ability and past teasing experiences were significant partial mediators in the relationship between autistic traits and depressive symptoms. However, contrary to expectations, social competence was not a significant mediator in the relationship between autistic traits and depressive symptoms. In addition, social problem-solving ability and past teasing experiences were significant partial mediators in the relationship between autistic traits and anxiety symptoms. This suggests that interventions to reduce anxious and depressive symptomatology in the ASD population should focus upon improving social problemsolving ability and reducing bullying experiences at school. These initial findings should be confirmed in the ASD population in future research. Crown Copyright ß 2009 Published by Elsevier Ltd. All rights reserved.

Keywords: Autism spectrum disorders Autistic traits Anxiety Depression

Autism spectrum disorders (ASDs) encompass Asperger’s syndrome (AS) and autism. These disorders affect approximately 6 in 1000 individuals worldwide (Shtayermman, 2007) and are typically characterised by a triad of impairments consisting of impaired social interaction, abnormal communication, and a markedly restricted repertoire of activities and interests (America Psychiatric Association [APA], 2000). In addition, individuals in the general population may exhibit autistic traits at a sub-clinical level. It is well understood that individuals with ASDs are more frequently diagnosed with depression and anxiety disorders than their typically developing peers (Ghaziuddin, 2005; Ketelaars et al., 2008; Meyer, Mundy, Vaughan Van Hecke, & Durocher, 2006; Shtayermman, 2007) and this is true of individuals with sub-clinical autistic traits as well (Ghaziuddin, 2005; Kunihira, Senju, Dairoku, Wakabayashi, & Hasegawa, 2006). Clinical depression according to the DSM-IV-TR is characterised by a disturbance in mood and physical and psychological symptoms (APA, 2000) such as fatigue, sleeping difficulties and loss of appetite (Oltmanns & Emery, 2004). Whilst depressive symptoms were identified in early cases of ASD by Kanner (1943) and Asperger (1944), it has only been in recent times that an increased focus has been placed on diagnosing depression in the ASD population. Systematic population-based studies of the prevalence of depression in individuals with ASDs are yet to be conducted, however, research thus far indicates that it is

* Corresponding author. Present address: Queensland Cerebral Palsy and Rehabilitation Research Centre, Paediatrics and Child Health, University of Queensland, Level 3 Foundation Building Royal Children’s Hospital, Herston, Brisbane 4029, Australia. Tel.: +61 7 3636 5539; fax: +61 7 3636 5538. E-mail addresses: [email protected], [email protected] (K. Whittingham). 1750-9467/$ – see front matter . Crown Copyright ß 2009 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.rasd.2009.10.012

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the most common co-occurring disorder in ASDs, with prevalence rates ranging from 5 to 82% (Ghaziuddin, 2005; Shtayermman, 2007). Depression can occur across the entire spectrum of ASDs. Some research has indicated that it is more common in high-functioning autism (HFA) and AS (Ghaziuddin, 2005) and it has been speculated that individuals with higher intellectual functioning may be more vulnerable to depression because they may be more aware of their social deficiencies (Barnhill & Smith-Myles, 2001). However, other research has suggested that individuals with lower functioning ASDs may be more at risk (Lainhart & Folstein, 1994). The presentation of depression in the ASD population is often described as atypical and may include increased withdrawal, obsessive–compulsive behaviours, changes in the character of obsessions, irritability, regression of skills, and psychotic behaviour (Ghaziuddin, 2005). Anxious symptamotology includes a combination of physical and psychological symptoms, such as a sense of impending doom, a feeling of tension or danger, palpitations, sweating, stomach aches, sleep disturbances, difficulty concentrating, restlessness, and irritability (Oltmanns & Emery, 2004). Within the ASD population, anxiety disorders have been reported in approximately 35% of individuals (Green, Gilchrist, Burton, & Cox, 2000; Kim, Szatmari, Bryson, Streiner, & Wilson, 2000; Leyfer et al., 2006). Individuals with HFA or AS tend to be diagnosed at higher rates (Kim et al., 2000). Whilst it is common for individuals with ASDs to experience the same psychological and physical features associated with anxiety in the general population (e.g., palpitations, sweating, sleep disturbances, and a sense of tension), they also commonly show increased social anxiety, panic, and obsessive–compulsive rituals (Bellini, 2004). Social competence is the ability to engage in satisfying social interactions including: initiating, facilitating, and maintaining successful relationships (Williams & Galliher, 2006). It can involve giving support, being assertive, being able to share private information about oneself, and being able to resolve conflicts (Shechtman & Katz, 2007). The social impairments of individiuals with ASDs are well understood (Capps, Sigman, & Yirmiya, 1995; Vickerstaff, Heriot, Wong, Lopes, & Dossetor, 2007). Research indicates that individuals with ASDs who have higher intellectual functioning may perceive themselves to be less socially competent than those of lower intellectual functioning (Vickerstaff et al., 2007), suggesting that they may be more aware of their social shortcomings. Research in the general population suggests that people who are less interpersonally competent tend to exhibit more depressive symptoms (Buhrmester, Furman, Wittenberg, & Reis, 1988; Connolly, 1989; Lewinsohn, Mischel, Chaplin, & Barton, 1980), possibly because they are less likely to build effective social networks to buffer against depression (Buhrmester et al., 1988). Lower self-pereceived social competence also predicts depression (Gable & Sheen, 2000; Segrin, 1990) and this effect has been found in children with ASDs as well (Vickerstaff et al., 2007). Social problem-solving refers to the ‘‘cognitive-affective-behavioural process by which a person attempts to identify, discover, or invent effective or adaptive coping responses for specific problematic situations encountered in everyday living’’ (D’Zurilla & Nezu, 1990, p. 156). Recent research in the area of social problem-solving has focused on a multi-dimensional approach developed by D’Zurilla and Nezu (1990), which emphasises two main points: an interest in solving problems that occur in real-life social situations, and the view that real-life problems are both a social learning process and a social skill. These are known as the problem orientation component and the skills component. The problem orientation component focuses on a relatively stable set of positive or negative cognitive-affective-behavioural responses that an individual brings to specific problematic situations. These are based on an individual’s past experiences with problems, how they have coped, and their beliefs about their ability to deal with certain situations (D’Zurilla & Nezu, 1990). Numerous studies have found that deficits in social problem-solving are linked to depressive and anxious symptomatology in the general population (Anderson, Goddard, & Powell, 2007; Chang & D’Zurilla, 1996; Haaga, Fine, Roscow Terrill, Stewart, & Beck, 1995; Marx, Willians, & Claridge, 1992). Social problem-solving deficits have been demonstrated in children and adults with HFA and AS, particularly with respect to the production of socially appropriate solutions (Bernard-Opitz, Sriram, & Nakhoda-Sapuan, 2001; Goddard, Howlin, Dritschel, & Patel, 2007). No research could be found examining the link between social problemsolving and depressive and anxious symptoms in the ASD population. Bullying is commonly thought to encompass both verbal and physical behaviours or social exclusion, which involves intended harm to the victim and includes an imbalance of power such that the victim finds it difficult to defend him or herself (Hunter, Boyle, & Warden, 2007). In the ASD population, verbal teasing has been found to be one of the most common forms of victimisation (Attwood, 2007) and is hence the focus of the present study. Teasing is a specific type of bullying, which involves verbal taunts about a wide range of personal and social factors including: appearance, performance, academic achievement, family background, and social behaviour (Storch et al., 2004). Whilst teasing can occur across the lifespan, teasing in childhood and adolescence have been associated with loneliness, low self-esteem, general or specific school related fears, anxiety or avoidance, depression, suicidal ideations, and suicide in young adulthood (Sweeting, Young, West, & Der, 2006). Previous research indicates that individuals with ASDs are at greater risk of being victims of bullying in childhood and adolescence (Little, 2002; Shtayermman, 2007). They may be targeted due to their aloofness and poor social skills (Dodd, 2005). Bullying in childhood has been found to predict depression and anxiety later in life, both in the general (Roth, Coles, & Heimberg, 2002; Storch et al., 2004; Strawser, Storch, & Roberti, 2005; Swearer, Song, Cary, Eagle, & Mickelson, 2001) and ASD populations (Dodd, 2005; Green et al., 2000; Mishna, 2003). The current study explored three possible mediators of the link between autistic traits in the general population and anxious/depressive symptomatology; social competence, social problem-solving skills and past teasing experiences. Based upon previous literature it was hypothesized that all three factors, social competence, social problem-solving skills and past teasing experiences would mediate the relationship between autistic traits and depressive symptomatology. It was hypothesized, based on the literature that social problem-solving skills and past teasing experiences would mediate the relationship between autistic traits and anxiety symptomatology.

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1. Method 1.1. Participants The participants were 231 undergraduate university students (114 males, 117 females) in Brisbane and Ipswich ranging in age from 17 to 35 years (M = 18.90, SD = 2.77). The majority of participants (65%) were recruited through the first year psychology pool at the University of Queensland in which students participated for course credit. Participants were also recruited by approaching students at engineering lectures and asking for volunteers (35%). Engineering students were targeted due to previous research demonstrating a high degree of autistic traits in that population (Baron-Cohen, Wheelwright, Skinner, Martin, & Clubley, 2001). 1.2. Materials 1.2.1. Autism Spectrum Quotient The Autism Spectrum Quotient (AQ; Baron-Cohen et al., 2001) is a standardised self-report questionnaire designed to measure the degree to which adults with normal intelligence have the traits associated with the autism spectrum. It comprises 50 questions, which can be broken into five domains; social skills, attention switching, attention to detail, communication, and imagination (Baron-Cohen et al., 2001). The AQ has a forced choice response format where respondents rate whether they definitely agree, slightly agree, slightly disagree, or definitely disagree with each statement. To avoid response bias, approximately half of the items were worded to produce a ‘disagree’ response and half to produce an ‘agree’ response in individuals with HFA (Baron-Cohen et al., 2001). Individual scores can range from 0 to 50, with higher socres indicating higher autistic traits. A useful cut-off for identifying individuals with a clinically significant level of autistic traits is 32 (Baron-Cohen et al., 2001). The AQ has reasonably good psychometric properties, with reported internal reliabilities of .67 (Hurst, Mitchell, Kimbrel, Kwapil, & Nelson-Gray, 2007) and .82 (Austin, 2005). In this study, the AQ demonstrated adequate internal consistency (a = .69). Good two week test–retest reliability (r = .70) has been reported in university populations (Baron-Cohen et al., 2001). 1.2.2. The Depression Anxiety and Stress Scales The Depression Anxiety and Stress Scales (DASS; Lovibond & Lovibond, 1995a) is a standardised self-report questionnaire, which was designed to measure the severity and frequency of three related negative affective states: depression, anxiety, and stress. It consists of 42 items with 14 questions corresponding to each state; where cognitive, affective and behavioural symptoms are assessed (Lovibond & Lovibond, 1995b). Respondents rate the extent to which they experienced each symptom over the past week according to a 4-point scale, which ranges from 0 (did not apply to me at all) to 3 (applied to me very much, or most of the time). Item scores are summed for each subscale to yield a total score (ranging from 0 to 42), which reflectes the frequency of an individual’s depressive, anxiety, or stress related symptomatology (Lovibond & Lovibond, 1995b). Cut-off points have been identified by Lovibond and Lovibond (1995a) to indicate the severity levels of depressive, anxiety, and stress related symptomatology. The DASS has excellent psychometric properties with reported internal reliabilities of .91, .84, and .90 for depression, anxiety, and stress respectively (Lovibond & Lovibond, 1995a). In this study, excellent Cronbach alphas of .92, .84, and .90 were demonstrated for depression, anxiety, and stress respectively. It also has excellent convergent validity with other scales designed to measure depression (Beck Depression Inventory: r = .74) and anxiety (Beck Anxiety Inventory: r = .81; Lovibond & Lovibond, 1995a). The current study focused on the depression and anxiety subscales. 1.2.3. Interpersonal Competence Questionnaire The Interpersonal Competence Questionnaire (ICQ; Buhrmester et al., 1988) is a 40 item multi-dimensional measure of interpersonal competence, with eight items measuring five dimensions. Each item briefly described an interpersonal situation or interaction. The five dimensions are: initiation of interactions and relationships, assertion of personal rights and displeasure with others, self-disclosure of personal information, emotional support of others, and management of interpersonal conflicts that arise in close relationships (Buhrmester et al., 1988). Respondents rated each item on a 5-point scale, which ranged from 1 (I’m poor at this; I’d feel so uncomfortable and unable to handle this situation, I’d avoid it if possible) to 5 (I’m extremely good at this; I’d feel very comfortable and could handle this situation very well). Whilst five subscale scores can be generated (ranging from 1 to 40), a total composite interpersonal score (ranging from 1 to 200) was calculated in the present study. Higher scores indicate greater levels of competence and comfort in handling situations involving interpersonal relationships (Buhrmester et al., 1988). The ICQ has excellent internal consistency, with reported ranges from .86 (Buhrmester et al., 1988) to .92 (Eberhart & Hammen, 2006) in undergraduate university samples. In this study, the ICQ demonstrated excellent internal consistency (a = .92). Excellent four week test–retest reliability has also been reported in a university sample (r = .78; Eberhart & Hammen, 2006). Evidence for convergent validity with questionnaires assessing related constructs has also been found (Eberhart & Hammen, 2006). 1.2.4. Social Problem-Solving Inventory-Revised (Short-form) The Social Problem-Solving Inventory-Revised (SPSI-R; D’Zurilla & Nezu, 1990) is a 52 item inventory that is based on the original 70 item Social Problem-Solving Inventory. For ease of administration, the shortened form (SPSI-R-SF; 25 items) of the SPSI-R was administered in the current study. The inventory comprises five different but related dimensions of problem-

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solving, with the aim to provide a comprehensive measure of perceived ability to solve problems as they occur in the ‘real world’. These five dimensions reflect either a dysfunctional or functional response and include both cognitive and behavioural aspects (D’Zurilla & Nezu, 1990). The five dimensions are: positive problem orientation, negative problem orientation, rational problem-solving, avoidant style, and impulsivity/carelessness style (D’Zurilla & Nezu, 1990). Each subscale has five items. Respondents rated the degree to which each statement described their typical problem-solving style according to a 5-point scale, ranging from 0 (not at all true of me) to 4 (extremely true of me). Whilst five subscale scores can be generated by summing the relevant subscale items (ranging from 0 to 20), a total social problem-solving score (ranging from 0 to 100) was calculated in the present study. Negatively phrased items were reverse scored (for both positive and negative scales), therefore higher scores always reflect greater problem-solving ability (D’Zurilla & Nezu, 1990). The SPSI-R-SF has excellent internal consistency, with reported ranges from .73 to .92 (Kant, D’Zurilla, & Maydeu-Olivares, 1997). In this study, the SPSI-R-SF demonstrated adequate internal consistency (a = .69). Excellent test–retest reliability has also been demonstrated, with reported ranges from .74 to .87 in adult and university samples (Haugh, 2006). The SPSI-R has been found to have good concurrent validity with the Problem-Solving Inventory and the Mends-Ends Problem-Solving Procedure, however, not to the extent that the SPSI-R could be seen as redundant (D’Zurilla & Nezu, 1990). 1.2.5. Teasing Questionnaire-Revised The Teasing Questionnaire-Revised (TQ-R; Storch et al., 2004) is a 29 item measure based on the original Teasing Questionnaire, which was designed to measure childhood memories of teasing. In the present study, participants were asked to remember back to primary and secondary school experiences. The questionnaire items were generated by extensively reviewing the peer victimisation and teasing literature and seeking guidance from anxiety and depression experts (Storch et al., 2004). This resulted in a more comprehensive measure, as traditional topics such as weight, appearance, and items addressing anxious or depressive symptomatology were also included (Storch et al., 2004). The measure consists of five unique constructs: teasing about performance, academic characteristics, social behaviour, family background, and appearance (Storch et al., 2004). For the TQ-R, respondents rated the degree to which each statement described their childhood teasing experiences according to a 5-point scale, which ranged from 0 (I was never teased about this) to 4 (I was always teased about this). Items were summed to yield a total composite score (ranging from 1 to 175), where higher scores indicated greater levels of childhood teasing. The TQ-R has excellent internal consistency, with reported ranges of .87 in undergraduate university samples (Ledley et al., 2005). In this study, the TQ-R demonstrated excellent internal consistency (a = .92). Excellent two week test–retest reliability has also been reported (r = .87; Ledley et al., 2005). 1.3. Procedure Participants were given a questionnaire pack, which consisted of a demographic sheet and the five questionnaires discussed above. Participants were asked to work individually and were told that there was no right or wrong answer. In addition, respondents were asked to answer all the questions, although they were informed that if they did not feel comfortable with certain questions they could leave them blank. Written instructions for each measure were provided at the start of each questionnaire. Upon completion of the questionnaire pack, participants were given an educational debriefing sheet, which described what the study was about, past findings, and what the researcher was hoping to find. Where circumstances permitted, verbal debriefing was given in addition to the written debrief. 2. Results 2.1. Preliminary analyses Less than 5% of the data was missing and these missing values were randomly dispersed. These cases were therefore retained for analysis. The central analysis method, bootstrapping, is robust and does not impose any multivariate assumptions. Analysis revealed that there were no significant gender differences when looking at: depressive symptoms, t (226) = .42, p = .67; anxiety symptoms, t (227) = .53, p = .60; social competence, t (223) = 2.20, p = .20; social problemsolving ability, t (219) = .53, p = .60; or past teasing experiences, t (224) = .70, p = .48. A gender difference was, however, found for autistic traits, as males (M = 18.38, SD = 5.80) exhibited significantly more autistic traits than females (M = 16.13, SD = 4.65), t (223) = 3.22, p = .001. This was expected, as it reflects the overrepresentation of ASDs in males. As no gender effects were found for depressive symptoms or anxiety symptoms, no covariates had to be controlled for in the multiple mediation analyses. The means, standard deviations and intercorrelations for all variables can be viewed in Table 1. 2.2. Statistical analyses Two multiple mediation analyses were undertaken for each model (one each for depressive and anxiety symptoms) via the bootstrapping method (Preacher & Hayes, 2008). Bootstrapping is a nonparametric approach to effect-size estimation and hypothesis testing that is recommended for use for multiple mediation models. This approach does not impose any multivariate assumptions as it generates an empirical approximation of the sampling distribution of a statistic by repeated random sampling of the data set (Preacher & Hayes,

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Table 1 Means, standard deviations, and intercorrelations for all variables (N = 231). Variables Anxiety symptoms Autistic traits Social competence Social problem-solving Teasing Means Standard deviations * **

Depressive symptoms

Anxiety symptoms

Autistic traits

Social competence

Social problem-solving

Teasing

.31** .22** .35** .37** 6.32 6.18

.41** .20** .26** 17.24 5.36

.39** .20** 97.49 16.59

.18* 58.81 12.32

48.80 15.77

**

.61 .38** .33** .43** .28** 7.75 7.93

p < .05. p < .01.

2008). To determine the significance of the mean indirect effects, 95% confidence intervals (CI) are obtained. If the CI do not include zero, then the indirect effect is considered statistically significant at the .05 level (Shrout & Bolger, 2002). A comparison study, of fourteen methods to test the statistical significance of mediation effects, found the bootstrapping method to be one of the superior methods due its simplicity, high statistical power, and low probability of making Type 1 errors (MacKinnon, Lockwood, Hoffman, West, & Sheets, 2002). To maintain equivalence to results of analyses which may be more familiar to some readers the following description of findings will also include results based on Sobel’s Test, which conform to Baron & Kenny, 1986 criteria. 2.3. Mediators of the link between autisic traits and depressive symptoms Results revealed that the proposed model was significantly different from zero, F (4, 196) = 23.56, p < .001, with R2 at .32. The adjusted R2 value of .31 indicated that 31% of the variability in depressive symptoms was predicted by knowing the level of autistic traits, social competence, social problem-solving ability, and past teasing experiences. Table 2 displays the results for depressive symptoms, which is further illustrated in Fig. 1. Autistic traits were found to be a significant positive predictor of depressive symptoms, such that as autistic traits increased, so did the level of depressive symptoms experienced, b = .58, t (201) = 5.94, p < .001. As Fig. 1 shows, the effect on depressive symptoms attributed to autistic traits was reduced from .58 (refer to total effect of autistic traits in Fig. 1) to .36 (refer to remaining direct effect in Fig. 1) by the set of three mediator variables, thus showing the presence of mediation. Results indicated that social competence, whilst accounting for approximately 26% of these mediation effects, that is .06 of the total .23 (refer to indirect effects of autistic traits in Table 2), did not significantly mediate the relationship between autistic traits and depressive symptoms as the CI ( .02 to .16) included zero. Social problem-solving ability, however, accounted for approximately 43% of the mediation effects, that is .10 of the total of .23 (refer to indirect effects of autistic traits in Table 2), with CI spanning .03 to .18. In addition, past teasing experiences accounted for approximately 30% of these mediation effects, that is .07 of the total .23 (refer to indirect effects of autistic traits in Table 2), with CI spanning .01–.16. These results are illustrated in Fig. 1. Both the bootstrap results and Sobel’s Test showed social problem-solving ability and past teasing experiences to be significant mediators beyond the p < .05 level (note that whenever zero is not contained within the bootstrap CI, the effect is considered significantly different from zero; refer to Table 3 for Sobel’s Test results). Furthermore, as the residual direct effects of autistic traits on depressive symptoms remained significant in the model (refer to remaining direct effect of autistic traits in Fig. 1), according to Baron and Kenny (1986) procedures, these results demonstrated partial rather than complete mediation by social problem-solving ability and past teasing experiences, as predicted. The results for the bootstrap and the Sobel’s test are reported in Table 2 and Table 3 respectively. 2.4. Mediators of the link between autistic traits and anxious symptoms Results revealed that the proposed model was significantly different from zero, F (3, 204) = 25.18, p < .001, with R2 at .27. The adjusted R2 value of .26 indicated that 26% of the variability in anxiety symptoms was predicted by knowing the level of autistic traits, social problem-solving ability, and past teasing experiences. Table 4 displays the results for anxiety symptoms, Table 2 Indirect effects of autistic traits on depressive symptoms via the mediators using the bootstrapping method (Bootstrap resamples = 1000, N = 201). Mediators

b

Total indirect effects Social competence Social problem-solving ability Past teasing experiences

.23 .06 .10 .07

CI lower .10 .02 .03 .01

CI upper

p

.38 .16 .18 .16

<.05* n.s. <.05* <.05*

Note: For CI, bootstrap analyses do not provide the exact significance levels but instead indicate that the results are (or are not) significant at the requested significance level. * p < .05.

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Fig. 1. Multiple mediation bootstrap analysis of relationships between autistic traits and depressive symptoms as mediated by social competence, social problem-solving ability, and past teasing experiences.

which is further illustrated in Fig. 2. Autistic traits were a significant positive predictor of anxiety symptoms, such that, as autistic traits increased so did the level of anxiety experienced, b = .37, t (208) = 4.75, p < .001. As Fig. 2 shows, the effect on anxiety symptoms attributed to autistic traits was reduced from .37 (refer to total effect of autistic traits in Fig. 2) to .21 (refer to remaining direct effect in Fig. 2) by the set of two mediator variables, thus showing the presence of mediation. Results indicated that social problem-solving ability accounted for approximately 40% of the mediation effects, that is .07 of the total .17 (refer to indirect effects of autistic traits in Table 4), with CI spanning .02–.14. In addition, past teasing experiences accounted for approximately 57% of these mediation effects, that is .10 of the total of .17 (refer to indirect effects of autistic traits in Table 4), with CI spanning .02–.19. These results are illustrated in Fig. 2. Both the bootstrap results and Sobel’s Test revealed past teasing experiences and social problem-solving ability to be significant mediators beyond the p < .05 level (refer to Table 5 for Sobel’s Test results). Furthermore, according to Baron and Kenny (1986) methods as the residual direct effects of autistic traits on anxiety symptoms remained significant in the model (refer to remaining direct effect of autistic traits in Fig. 2), these results indicated partial mediation as predicted for both Table 3 Indirect effects of autistic traits on depressive symptoms via the mediators using Sobel’s Test (N = 228). Mediators

b

Z

p

Total indirect effects Social competence Social problem-solving ability Past teasing experiences

– .04 .20 .07

– 1.11 2.61 2.06

–

Note: Dashes indicate that this method does not provide a statistical test for these indirect effects. * p < .05.

.27 .009* .03*

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421

Table 4 Indirect effects of autistic traits on anxiety symptoms via the mediators using the bootstrapping method (Bootstrap resamples = 1000, N = 208). Mediators

b

CI lower

CI upper

p

Total indirect effects Social problem-solving ability Past teasing ability

.17 .07 .10

.07 .02 .02

.29 .14 .19

<.05* <.05* <.05*

Note: For CI, bootstrap analyses do not provide the exact significance levels but instead indicate that the results are (or are not) significant at the requested significance level. * p < .05.

Fig. 2. Multiple mediation bootstrap analysis of relationships between autistic traits and anxiety symptoms as mediated by social problem-solving ability and past teasing experiences. Table 5 Indirect effects of autistic traits on anxiety symptoms via mediators using Sobel’s Test (N = 229). Mediators

b

Z

p

Total indirect effects Social problem-solving ability Past teasing experiences

– .13 .11

– 2.46 2.99

– .01* .001*

Note: Dashes indicate that this method does not provide a statistical test for these indirect effects. * p < .05.

social problem-solving ability and past teasing experiences. Results for the bootstrap and the Sobel’s Test are reported in Tables 4 and 5 respectively. 3. Discussion A significant positive relationship emerged between autistic traits and depressive symptoms, such that individuals who rated themselves as having higher levels of autistic traits also reported higher levels of depressive symptoms. Results also revealed that social problem-solving ability and past teasing experiences were significant partial mediators in the relationship between autistic traits and depressive symptoms, as predicted. However, contrary to expectations, social competence was not a significant mediator in the relationship between autistic traits and depressive symptoms. Furthermore, social problem-solving ability was found to account for a greater proportion of the mediation effects than past teasing experiences, thus suggesting it may play a larger role in determining depressive symptoms.

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A significant positive relationship emerged between autistic traits and anxiety symptoms, such that individuals who rated themselves as having higher levels of autistic traits also reported higher levels of anxiety symptoms. Furthermore, social problem-solving ability and past teasing experiences were found to be significant partial mediators in the relationship between autistic traits and anxiety symptoms, thus supporting the final hypotheses. Unlike the depression model, past teasing experiences were found to account for a greater proportion of the mediation effects than social problem-solving ability. Whilst social problem-solving ability and past teasing experiences were significant mediators in both models, the results of this study suggest that social problem-solving ability may be more important in determining depressive symptoms and past teasing experiences may be a more important risk factor for the development of anxiety symptoms. 3.1. Social problem-solving ability The finding that social problem-solving ability was a significant mediator in the relationship between autistic traits and depressive symptoms and autistic traits and anxiety symptoms is consistent with previous research examining the link between social problem-solving and depressive/anxious symptoms (Anderson et al., 2007; Haaga et al., 1995; Haugh, 2006; Marx et al., 1992). However, no known previous research has established that social problem-solving ability is a mediator of the link between autistic traits and depressive/anxious symptoms in young adults. As previously discussed, the social problem-solving model involves a problem orientation component (negative or positive) and a skills component (D’Zurilla & Nezu, 1990). Two explanations of the current findings are therefore possible. Individuals exhibiting autistic traits could be vulnerable to depressive and anxious symptoms because they are applying maladaptive problem-solving styles to everyday problem-solving (e.g., negative problem orientations) or because they have a deficit in particular adaptive styles (e.g., rational problem-solving style), which buffer against the effects of depressive and anxious symptomatology. In addition, it is also possible that a combination of both of these processes is occurring. This research could be expanded by examining how particular social problem-solving styles affect depressive and anxious symptoms in the ASD population. Further understanding in this area could have important implications for interventions as how an individual attempts to solve a problem (maladaptive or not) may be a factor for consideration in enhancing intervention strategies for individuals with ASD. 3.2. Social competence Contrary to expectations, self-perceived social competence was not a significant mediator in the relationship between autistic traits and depressive symptoms. It should be acknowledged that this study measured self-perceived social comptence rather than actual social competence. It may be the case that actual social competence does mediate the link. However, a significant relationship between autistic traits and self-perceived social competence was found such that individuals with higher levels of autistic traits exhibited lower self-perceived social competence suggesting that their judgements are likely to be accurate. It may be the case that for individuals with autistic traits that self-perceived social competence is not a predictor of depressive symptoms because individuals with autistic traits may have a lesser need to maintain successful relationships (Dodd, 2005) and social support may not be as effective a buffer against depression for individuals with autistic traits as it is in the general population. It could be the case that for individuals with autistic traits it is the difficulty in negotiating the daily social world, in finding socially appropriate solutions to everyday problems and coping with changes in everday life that is important. In other words, social problem-solving deficits could be causing significant psychological distress rather than the difficulty in establishing and maintaining sucessful realtionships, or social competence deficits. Further research investigating these findings in the ASD population would be valuable as this could inform intervention. These premilinary results suggest that the main focus of interventions for ASDs should be on improving social problem-solving skills rather than on improving social competence skills in order to reduce depressive and anxious symptoms and improve quality of life. 3.3. Past teasing experiences Past teasing experiences were a significant mediator in the relationship between autistic traits and depressive symptoms and between autistic traits and anxiety symptoms. This finding is consistent with previous research in the general and ASD populations, which found that past teasing experiences were predictive of depressive (Mishna, 2003; Roth et al., 2002; Storch et al., 2004) and anxiety related symptoms or disorders (Green et al., 2000; Strawser et al., 2005). This study adds to the literature in establishing past teasing experiences as a link between autistic traits and depressive/anxious symptoms. This finding suggests that reducing the bullying experiences that individuals with ASD commonly experience throughout schooling may be an important part of improving their psychological functioning long-term. It should be noted that an alternative explanation for the findings is that individuals who are currently distressed may have recalled their childhood experiences in an overly negative manner, thus influencing the results. Future research could account for this by using collateral reports (e.g., parent, peers, siblings) of teasing.

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