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Purpose To examine the associations of trait anxiety (STAI), social anxiety (SIAS), depression (BDI-II), and personality features (ADP-IV) with three measures of stuttering severity: %SS, Stuttering Severity, Instrument, and the Overall Assessment of the Speaker's Experience of Stuttering. Method Fifty adults with a history of stuttering served as participants. Participant scores on trait, anxiety, social anxiety, depression, and personality features were entered into a regression analysis, with the criterion variables (DVs) being: %SS, SSI-3, OASES total score. In order to explore the OASES, further, each of the four OASES subscales were also examined. A separate regression was conducted for, each dependent variable. Results The OASES total score model was significant (p < .0001) and revealed that social anxiety and, trait anxiety were the only significant predictors, with medium effect sizes noted for both variables. In contrast, percent syllables stuttered and the SSI were not significantly associated with psychological, variables, suggesting that anxiety may not always be related to overt indicators of stuttering. Depression and personality dysfunction were not significantly associated with any measure of, stuttering severity. Conclusion Anxiety in the form of social and trait anxiety are significantly associated with stuttering, severity as indicated by the OASES. Traditional procedures for assigning severity ratings to individuals, who stutter based on percent syllables stuttered and the Stuttering Severity Instrument are not, significantly related to psychological processes central to the stuttering experience. Depression and, personality characteristics do not meaningfully account for stuttering. Educational objectives: The reader will be able to: (a) differentiate forms of anxiety that are likely to be associated with stuttering (b) understand the importance of determining features of stuttering that go beyond the obvious, surface characteristics of stuttering frequency, and (c) discuss the important clinical and theoretical implications for understanding the degree of psychological dysfunction that is likely to be characteristic of those who stutter.

The purpose of this investigation, as it was for a companion study (Manning & Beck, 2013), was to take another look at the role of psychological factors among adults who stutter. Recently, Iverach and colleagues (2009a) (see below for details) reported extraordinarily high levels of Axis II personality dysfunction in a sample of 92 adults who were seeking treatment for stuttering. In light of studies examining both anxiety and depression among individuals who stutter, the present investigation is designed to compare the associations of anxiety, depression, and personality dysfunction with stuttering severity. Because stuttering has been recognized as a multidimensional construct (e.g., Conture, 2001 and Riley and Riley, 1984, Smith & Kelly, 1997), three separate measures of stuttering were examined (percent syllables stuttered, Stuttering Severity Instrument, and Overall Assessment of the Speaker's Experience of Stuttering). For many years, it has been apparent to researchers in the field of fluency disorders that anxiety is a common characteristic for speakers who stutter. Researchers have repeatedly documented this association using a variety of physiological measures such as heart rate, blood pressure, EEG, and skin conductance response (e.g., Berlinsky, 1955, Brutten, 1963, Fletcher, 1914, Knott et al., 1959, Robbins, 1920 and Travis et al., 1936) and self-report measures such as the Endler Multidimensional Scales (e.g., Messenger, Onslow, Packman, & Menzies, 2004), the most often used measure, the State and Trait Anxiety Inventory (e.g., Blood et al., 1994, Blumgart et al., 2010, Craig, 1990, Craig et al., 2003, Ezrati-Vinacour and Levin, 2004, Miller and Watson, 1992 and Mulcahy et al., 2008), and the Taylor Manifest Anxiety Scale (e.g., Boland, 1953 and Kraaimaat et al., 1991). In considering this literature, investigators have recently begun to recognize that different types of anxiety-related processes may be relevant. For example, Blumgart et al. (2010) used five measures of anxiety including the State and Trait Anxiety Inventory (STAI) and several measures of social anxiety to compare 200 adults who stuttered with 200 adults who were fluent. The STAI assesses general levels of anxiety and tension, captured on a state scale (which assesses current levels of anxiety) and a trait scale (which assesses usual or typical levels of anxiety). In contrast, social anxiety measures focus on an individual's anxiety in social-evaluative settings. Blumgart et al. found that adults who stuttered had significantly greater levels of state and trait anxiety, as well as social anxiety, with moderate to large effect sizes noted on all anxiety measures. Stuttering severity, as indicated by percent syllables stuttered (%SS) was unrelated to any anxiety measure. Blumgart et al. (2010) concluded that stuttering influences general anxiety (trait), current anxiety (state), and social anxiety. In contrast, other investigators found few significant differences in anxiety levels when comparing individuals who stutter with control groups of fluent speakers (e.g., Andrews and Craig, 1988, Andrews and Harris, 1964, Andrews et al., 1983, Hedge, 1972, Cox et al., 1984, Craig and Hancock, 1996, Lanyon et al., 1978, Miller and Watson, 1992, Molt and Guilford, 1979, Peters and Hulstijn, 1984 and Prins, 1972). The following literature highlights several factors that influence the detection of anxiety and other forms of psychological distress in participants who stutter. 1.1. The possibility of depression Because it is common for anxiety and depression to co-occur (Barlow, 2002, Gurney et al., 1970 and Leckman et al., 1983), depression has also been considered a possible psychological process that may occur with stuttering. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; American Psychiatric Association, 2000), depression is characterized by five or more symptoms that are dissimilar to one's previous functioning (e.g., depressed mood, loss of interest or pleasure, insomnia, loss of energy) during a two week period. The relatively few investigations of depression for those who stutter have generally yielded equivocal results. While some investigators have reported higher levels of self-reported depressive symptoms for individuals who stutter ( Liu et al., 2001, Tran et al., 2011 and Yanagawa, 1973), the findings of other studies have failed to support the impression that those who stutter are more depressed than their fluent peers ( Bray et al., 2003 and Miller and Watson, 1992). Miller and Watson studied the relationships among communication attitude, anxiety and depression, with 53 participants who stuttered (mean age: 41; range: 16–68) and a control group of nonstuttering participants (mean age: 41; range: 17–67). Each group contained 38 males and 14 females. The two groups were matched for age, gender, ethnic background, and highest education level. Using a 5-point scale, participants self-rated their severity of stuttering, resulting in very mild to mild: n = 19, moderate: n = 23, severe to very severe: n = 10. The results indicated that communication attitude became more negative as self-rated stuttering severity increased. However, no significant group differences were found for anxiety (State-Trait Anxiety Inventory (STAI) ( Spielberger et al., 1983) or depression (Beck Depression Inventory (BDI) ( Beck, 1987) in this study. Mean depression scores for both stuttering and nonstuttering groups fell within the normal range of 0–9. In contrast to the findings of Miller and Watson (1992), a recent investigation by Tran et al. (2011) found that, in comparison to a matched group of non-stuttering controls, adults who stuttered (N = 200) were significantly more likely to report elevated levels of negative mood symptoms including depressive mood. These results are in contrast to earlier research by these authors ( Craig & Tran, 2006) and as Tran et al. (2011) suggest, may be due to the factor structure of the self-report Symptom Checklist (Revised, SCL-90-R, Derogatis, 1994) that was used for the stuttering dataset. Given the inconsistency of these results, the relatively few studies of depression, and the extreme levels of anxiety recently reported by Iverach et al., 2009a and Iverach et al., 2011 the possibility of elevated levels of depression was considered in the current investigation. 1.2. The extent of personality dysfunction Research concerning the relationship of anxiety and stuttering has, for the most part, supported the idea that those who stutter are likely to experience elevated levels of anxiety, particularly as it relates to circumstances that require verbal communication. Although the role of depression is at present unclear, recent discussion in the literature has emphasized the role of possible personality dysfunction among individuals who stutter. A series of investigations and commentary by Iverach and colleagues (e.g., Iverach et al., 2009a, Iverach et al., 2009b, Iverach et al., 2010 and Iverach et al., 2011) suggest that the experiences of those who stutter through childhood and adolescence are likely to result in serious personality dysfunction. For example, Iverach et al. (2009a) employed a self-report screening measure with a sample of 92 individuals who were seeking treatment for stuttering, finding that 64.1% met criteria for at least one personality disorder, a nearly threefold increased odds, relative to an age- and gender-matched control sample. Remarkably, Iverach et al. (2009a) also found a 38.15% rate of Personality Disorders among their control sample, a rate considerably higher than the 10–15% consistently found by epidemiologists in the general population (Schotte et al., 2004). Subsequent commentary by Manning and Beck (2011) noted several issues with the self-report measure used by Iverach et al. (2009a) that may have resulted in the extraordinarily high levels of personality dysfunction for both the experimental and control groups. To consider this possibility, Manning and Beck (2013) studied 50 adults undergoing treatment for stuttering using the Assessment of the DSM-IV Personality Disorders (ADP-IV, Schotte and De Doncker, 1994 and Schotte and De Doncker, 1996). This measure provides for both categorical and dimensional assessment of the 10 categories of DSM-IV personality disorders (PD) resulting in neither over-identification nor the typical high co-morbidity among PD categories that characterizes other self-report instruments (Schotte et al., 1998). Further, the ADP-IV can differentiate between members of the general population and psychiatric inpatients (Schotte et al., 2004) and has good convergent validity with the Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II, First et al., 1997), the preferred procedure for diagnosing personality disorders. Manning and Beck noted rates of possible personality disorders in their sample that approximated rates observed in general community samples using structured clinical interviews administered by trained interviewers. This report suggests that personality dysfunction may not be a notable feature of stuttering. In order to examine the association of personality features (and possible dysfunction) with stuttering, measures of personality features were included in the present study. As noted in this review of anxiety, depression, and personality, the literature suggests that participant selection and methodological issues may play a role in detecting psychological factors for those who stutter. 1.3. Considering speaking versus non-speaking tasks An important aspect of the methodology used in identifying psychological processes among those who stutter is the degree to which the experimental procedures elicit communication pressure. Differences in anxiety levels between stuttering and nonstuttering participants are typically absent during nonverbal tasks (Berlinsky, 1955, Gray and Karmen, 1967 and Peters and Hulstijn, 1984). Peters and Hulstijn (1984), for example, compared heart rate, vasomotor responses, skin conductance activity, and ratings of subjective anxiety for 24 adults who stuttered and a matched group of fluent speakers. Participant responses were measured before and during a series of speech tasks (reading aloud and conversation with another person) and non-speech tasks (motor and intelligence tasks). Peters and Hulstijn found few differences between participants who stuttered and those who did not with respect to physiological arousal, with both groups showing increased arousal prior to and during speech tasks, relative to the non-speech tasks. Individuals who stuttered showed significantly increased anxiety levels during the speech tasks, relative to participants who did not stutter. This study documents the saliency of speech tasks in evoking psychological reactions such as anxiety among persons who stutter. 1.4. The influence of treatment Craig (1990) and Craig et al. (2003) noted that most research on anxiety and related psychological processes among those who stutter has included only individuals who were seeking or receiving treatment. Craig et al. (2003) summarized the literature by noting that those who seek treatment characteristically have greater levels of stuttering severity as well as higher levels of anxiety than their fluent peers. On the other hand, anxiety levels of those who have successfully completed treatment are often comparable to their fluent peers. In order to investigate this aspect of participant selection, Craig et al. (2003) interviewed randomly selected individuals from a community sample over the phone by administering a series of questions concerning stuttering. Sixty-three individuals were identified and confirmed as individuals who stuttered. Of this group, 33 had not received treatment and 18 had received therapy for stuttering at least once during their lifetime. STAI scores from these two subgroups groups were compared to those from 102 fluent individuals from a previous study (Craig, 1990). Results indicated that there were no significant differences in anxiety levels between individuals who stuttered who had and had not received therapy. Moreover, no significant differences in anxiety emerged when comparing individuals who stutter who had never received therapy with the nonstuttering controls. However, when comparing the nonstuttering controls with the sample of 18 individuals who had received therapy, a significant difference was noted (controls: mean = 35.8, SD = 7.0, stuttering individuals who had sought therapy: mean = 40.1, SD = 9.6). Seeking to examine whether stuttering severity was associated with greater anxiety, Craig et al. (2003) subdivided their sample based on percentage of syllables stuttered (%SS). No differences in anxiety were noted between those with more frequent stuttering and those with less frequent stuttering. Craig et al. (2003) observed that most of the difference in anxiety scores was attributed to those participants who had sought treatment, presumably reflecting greater levels of social and psychological concern related to fluency. Treatment-seeking thus is associated with greater levels of anxiety in this report. 1.5. Psychological processes and stuttering severity A final but critical issue in determining the relationship of various psychological processes and stuttering severity is the procedure for determining severity. For many decades, research in fluency disorders focused on the frequency of stuttering as a major, and often the only, standard of stuttering severity. It is common in many manuscripts and textbooks to see the term ‘severity’ used interchangeably with frequency counts such as the percentage of syllables or words stuttered. Although this perspective about the nature of stuttering severity is not surprising among members of the general community, it is unfortunately found in the professional literature as well. Aside from problems establishing valid and reliable frequency counts (e.g., Cordes and Ingham, 1996 and Kully and Boberg, 1988), measurements of the overt features of stuttering such as the frequency of stuttering events fail to capture the breadth and depth of the stuttering experience (Smith, 1999, Smith and Kelly, 1997 and Starkweather and Givens-Ackerman, 1997). This may be why Craig et al. (2003), using %SS, found no difference in anxiety for participants who were rated as less (<6%SS) or more (>6%SS) severe. Another commonly used measure is the Stuttering Severity Instrument (SSI-3) (Riley, 1994). This measure provides a somewhat more comprehensive assessment in that it includes the frequency of stuttering in percent syllables stuttered as well as the duration of the three longest stuttering events and the presence of “physical concomitants” associated with effort and struggle behaviors that often accompany stuttering events. Along with issues of reliability (Hall et al., 1987 and Lewis, 1995), the SSI however, does not account for many central features of stuttering including the individual's avoidance, reactions to stuttering, problems during daily communication, and the many coping responses that result in a restricted lifestyle (Plexico et al., 2009). A relatively recent measure of stuttering severity is the Overall Assessment of the Speaker's Experience of Stuttering (OASES) (Yaruss & Quesal, 2008). The OASES was designed to obtain information about the totality of the stuttering experience as delineated by the World Health Organization's International Classification of Functioning, Disability, and Health (ICF; WHO, 2001). The majority of the items deal with perceptions of functional communication and quality of life. According to the authors ( Yaruss & Quesal, 2006), the purpose of the OASES is to measure “the overall impact of stuttering through assessment of multiple aspects of the disorder” (p. 104). The OASES expands assessment of the stuttering experience by assessing the nature of disability and social handicap experienced by each speaker. The procedure allows the individual to report on his or her cognitive and affective responses to the stuttering experience from four perspectives including (I) general information about stuttering, (II) reactions to stuttering, (III) difficulty experienced during daily communication, and (IV) quality of life. The measure also provides a stable indication of the impact of stuttering over time and speaking conditions ( Constantino et al., 2012). In contrast to measures of %SS and the SSI that show a high degree of variability, Constantino et al. (2012) demonstrated the consistency of the OASES across multiple assessments of speaking and reading tasks. Given the noted variability of the surface (objective) features of stuttering (particularly frequency of stuttering) across time and place, the OASES provides an alternative indication of the overall impact of stuttering from the perspective of the individual who stutters. 1.6. Summary and purpose From the perspective of past and current research, it is well known that elevated levels of anxiety during verbal communication are a common response for those who stutter, particularly during speaking activities. The majority of research has indicated that this psychological response is elevated compared to fluent speakers, but for most people, is not extreme. However, recent findings suggest that depressed mood and personality dysfunction may be more common for people who stutter than previously suspected. With estimates of the nature of the psychological problems ranging from non-significant to extreme, the question addressed in the current study focuses on the relative association of these psychological factors with various dimensions of stuttering severity. Anxiety, depression, and self-reported personality features were also assessed. We hypothesized that anxiety would emerge as the only significant psychological factor associated with stuttering severity, and that this association would only be noted with the OASES, which assesses the individual's experience of stuttering and its impact on his or her daily functioning. We did not expect that any of the psychological variables (anxiety, depression, or personality features) would show significant associations with %SS or the SSI, in keeping with previous work in this area (e.g., Craig et al., 2003).