Inflammation is gaining support as a biological mediator between stress and many negative outcomes that have heightened risk during adolescence (e.g., mood disorders). Thus, an important line of inquiry is evaluating whether risk factors for mood psychopathology also are associated with heightened inflammatory responses to stress during this developmental period. Two prominent risk factors that interact to predict mood psychopathology are reward sensitivity and perseverative cognitive response styles, which also have been associated with heightened inflammatory proteins. These factors could influence inflammation by synergistically amplifying stress reactivity. Ninety-nine late adolescents (M age = 18.3 years, range = 15.6–21.9 years) completed measures of reward sensitivity, cognitive response style, and blood draws before and 60-min after a modified Trier Social Stress Task to determine levels of inflammation. Higher reward drive interacted with more perseverative response style ratios (rumination relative to distraction + problem-solving) to predict larger increases in interleukin-6 (a proinflammatory protein). Follow-up analyses found that reward drive interacted with all three components of the ratio to predict change in interleukin-6. Thus, these results suggest that high reward drive and perseverative cognitive response styles are associated with increased inflammatory response to social stress in adolescents, a potential physiological mechanism linking these risk factors to mood psychopathology during this developmental period.

A promising approach to reducing the phenotypic heterogeneity of psychiatric disorders involves the identification of homogeneous subtypes. Careful study of comorbidity in obsessive‐compulsive disorder (OCD) contributed to the identification of the DSM‐5 subtype of OCD with tics. Here we investigated one of the largest available cohorts of clinically diagnosed trichotillomania (TTM) to determine whether subtyping TTM based on comorbidity would help delineate clinically meaningful subgroups.

This chapter describes the mood disorders as well as their diagnosis, symptoms, dimensions, and risk factors. It reviews what is known about the causes and treatment of the mood disorders from various theoretical perspectives. Due to the variation in mood disorders, from more mild and chronic to more severe and episodic, many researchers support the notion that both depression and bipolar disorder should be considered as continua or spectra as opposed to the discrete disorders. In addition to the important distinctions between bipolar and depressive disorders, there are certain dimensions that researchers and clinicians have found useful in classifying mood disorders. The chapter discusses three dimensions: psychotic versus non-psychotic, early versus late onset, and endogenous versus reactive. It describes the importance of life events in the onset of mood disorders, because this was the original basis of the endogenous-reactive distinction.

Background Stress is consistently implicated in depression. Using a vulnerability-stress framework, the hypothalamic-pituitary-adrenal (HPA) axis may be one factor affecting the stress-depression association. However, the interactive influence of recent life stress and HPA axis functioning on depressive symptoms remains unclear. It is particularly important to understand the synergistic association during adolescence, as this is a developmental period associated with a high risk for depression. Methods A community sample of 58 adolescents (67% female, 59% Caucasian; mean age, 15.07 years) participated. Adolescents completed a well-validated measure of depressive symptoms and a structured life events interview to assess recent life stress. Hair cortisol concentration was obtained to measure cumulative exposure to HPA axis functioning. Results Recent life stress and cumulative HPA axis exposure measured through hair cortisol were directly associated with higher depressive symptoms. Further, cumulative HPA axis exposure moderated the relationship between recent life stress and depressive symptoms. The recent life stress-depression association occurred for adolescents who experienced average and high, but not low, levels of cumulative HPA axis exposure. Conclusions The current study builds on prior work and finds both a direct and interactive association of recent life stress and cumulative HPA axis functioning with depressive symptoms during adolescence. Identifying youth who experience high levels of HPA axis exposure is important to prevent the onset of depression.

Trichotillomania/hair pulling disorder (HPD) and excoriation/skin picking disorder (SPD) are childhood-onset, body-focused repetitive behaviors that are thought to share genetic susceptibility and underlying pathophysiology with obsessive–compulsive disorder (OCD) and Tourette syndrome (TS). We sought to determine the prevalence of DSM - 5 HPD and SPD in TS patients, and to identify clinical factors most associated with their co-morbidity with TS. Participants included 811 TS patients recruited from TS specialty clinics for a multi-center genetic study. Patients were assessed using standardized, validated semi-structured interviews. HPD and SPD diagnoses were determined using a validated self-report questionnaire. HPD/SPD prevalence rates were calculated, and clinical predictors were evaluated using regression modeling. 3.8 and 13.0% of TS patients met DSM - 5 criteria for HPD and SPD, respectively. In univariable analyses, female sex, OCD, and both tic and obsessive–compulsive symptom severity were among those associated with HPD and/or SPD. In multivariable analyses, only lifetime worst-ever motor tic severity remained significantly associated with HPD. Female sex, co-occurring OCD, ADHD, and motor tic severity remained independently associated with SPD. This is the first study to examine HPD and SPD prevalence in a TS sample using semi-structured diagnostic instruments. The prevalence of HPD and SPD in TS patients, and their association with increased tic severity and co-occurring OCD, suggests that clinicians should screen children with TS and related disorders for HPD/SPD, particularly in females and in those with co-occurring OCD. This study also helps set a foundation for subsequent research regarding HPD/SPD risk factors, pathophysiology, and treatment models.

OBJECTIVE:Trichotillomania (TTM) is associated with high rates of co-occurring depression and anxiety disorders. What the co-occurrence of TTM, depression or anxiety disorders means clinically and cognitively, however, has garnered little research attention.METHODS:About 530 adults with TTM were examined on a variety of clinical measures including symptom severity, psychosocial measures of functioning, psychiatric comorbidity and neurocognitive testing assessing motor inhibition and cognitive flexibility. Clinical features and cognitive functioning were compared between TTM patients with current comorbid major depressive disorder (MDD), a current anxiety disorder, both MDD and an anxiety disorder, or neither.RESULTS:Of 530 participants, 58 (10.3%) had MDD only, 97 (18.3%) had an anxiety disorder only, 58 (10.3%) had both MDD and an anxiety disorder, and 317 (59.8%) had neither. For almost all clinical measures, those with MDD only reported worse symptoms than those with an anxiety disorder only, and the combination of MDD and an anxiety disorder reported the worst level of symptom severity.CONCLUSIONS:These results suggest that adults with TTM and co-occurring MDD and anxiety disorders exhibit unique clinical differences. The clinical differences may also have treatment implications.

Little is known about the causes of body dysmorphic disorder (BDD), but researchers have proposed a diathesis-stress model. This study uses a patient-centered approach to identify stressful events to which patients attribute the development of their BDD symptoms. An Internet-recruited sample of 165 adults with BDD participated. A large minority of participants attributed the development of their BDD to a triggering event. Bullying experiences were the most commonly described type of event. Additionally, most events were interpersonal and occurred during grade school or middle school. There were no differences in severity of psychosocial outcomes between participants who did or did not attribute their BDD to a specific triggering event. However, participants who specifically attributed their BDD development to a bullying experience had poorer psychosocial outcomes (i.e., perceived social support, depression severity, functional impairment, quality of life) compared to those who attributed their BDD development to another type of triggering event.

Trichotillomania (TTM) and eating disorders (ED) share many phenomenological similarities, including ritualized compulsive behaviors. Given this, and that comorbid EDs may represent additional functional burden to hair pullers, we sought to identify factors that predict diagnosis of an ED in a TTM population. Subjects included 555 adult females (age range 18–65) with DSM-IV-TR TTM or chronic hair pullers recruited from multiple sites. 7.2% (N=40) of our TTM subjects met criteria for an ED in their lifetime. In univariable regression analysis, obsessive-compulsive disorder (OCD), Yale-Brown Obsessive Compulsive Scale (Y-BOCS) worst-ever compulsion and total scores, certain obsessive-compulsive spectrum disorders, anxiety disorder, attention-deficit/hyperactivity disorder (ADHD), and substance disorder all met the pre-specified criteria for inclusion in the multivariable analysis. In the final multivariable model, diagnosis of OCD (OR: 5.68, 95% CI: 2.2–15.0) and diagnosis of an additional body-focused repetitive behavior disorder (BFRB) (OR: 2.69, 95% CI: 1.1–6.8) were both associated with increased risk of ED in TTM. Overall, our results provide further support of the relatedness between ED and TTM. This finding highlights the importance of assessing for comorbid OCD and additional BFRBs in those with TTM. Future research is needed to identify additional predictors of comorbid disorders and to better understand the complex relationships between BFRBs, OCD and EDs.

BACKGROUND Trichotillomania (TTM) appears to be a fairly common disorder, yet little is known about sex differences in its clinical presentation. Long thought to be a primarily female disorder, males with TTM may have unique clinical presentations. METHODS Participants with TTM (N = 462) were examined on a variety of clinical measures including symptom severity, functioning, and psychiatric comorbidity. Clinical features were compared between males (n = 27) and females (n = 435). RESULTS There were many similarities in the clinical presentations of males and females with TTM. Males with TTM, however, were more likely to pull from their face, arms, and torso, and were more likely to suffer from a co-occurring substance use disorder. Females were more likely to be younger and less likely to be married. CONCLUSIONS This study suggests that, although few males seek treatment for TTM, sex differences may be an important clinical factor when assessing and treating this disorder. Further research is needed to validate these findings and identify whether treatments should be tailored differently for males and females with TTM.

BACKGROUNDSkin-picking disorder (SPD) was recognized as its own entity for the first time in DSM-5. The existing SPD literature is limited and, to date, no study has examined the differences between clinical and sub- clinical SPD. Identifying differences between these 2 groups may improve diagnostic accuracy, treatment, and prevention efforts.METHODSIsraeli adults (N = 4,325) from 2 previous studies were examined for the presence of clinical and subclinical SPD. Individuals with clinical SPD (n = 150) vs subclinical SPD (n = 219) were compared on skin-picking characteristics, psychological phenomena, and clinical correlates.RESULTSThere were many similarities between clinical and subclinical skin pickers. Individuals with clinical SPD, however, had more severe skin picking, greater associated functional impairment, greater perceived stress, and greater depressive and obsessive-compulsive symptoms, and were also more likely to have a first-degree relative with SPD.CONCLUSIONSThis study suggests that although there are some similarities between clinical and subclinical SPD, there also are distinct differences in the clinical presentation. Understanding these differences may be an important factor in treatment and prevention planning.

BACKGROUND Trichotillomania (TTM) and skin-picking disorder (SPD) have been characterized as body-focused repetitive behavior disorders (BFRBs). Because BFRBs frequently co-occur, we sought to discover the similarities and differences for individuals having both TTM and SPD as opposed to 1 of these disorders. METHODS Participants with primary TTM (N = 421) were evaluated regarding the comorbidity of SPD, and participants with primary SPD (N = 124) were evaluated regarding the comorbidity of TTM. The effects of comorbidity overlap on demographic and clinical measures were evaluated. RESULTS Of the 421 participants with primary TTM, 61 (14.5%) had co-occurring SPD. Of 124 participants with primary SPD, 21 (16.9%) had comorbid TTM. Participants with primary TTM and comorbid SPD had significantly more severe trichotillomania symptoms and were more likely to have major depressive disorder than those with TTM alone. Participants with primary SPD and comorbid TTM reported significantly more severe skin-picking symptoms than those who had only SPD. CONCLUSIONS Individuals with co-occurring TTM and SPD may have more problematic symptoms with the primary repetitive behavior. Hair pullers with comorbid SPD were more likely to have comorbid depression. Evaluating patients for multiple BFRBs may be important to assess the severity of symptoms and may have treatment implications.

Researchers have proposed emotion regulation (ER) as one model of trichotillomania (TTM). This model suggests that hair pulling may function as a maladaptive coping mechanism given difficulty managing negative emotions such as anger. This study compared hair pullers versus the normative population on trait anger, anger expression, and anger control and explored whether there is a relationship between anger variables and hair pulling severity. 158 adult females with TTM or chronic hair pulling completed self-report measures of anger and hair pulling severity. Hair pullers reported significantly higher rates of inwardly directed anger and more difficulty controlling their inward anger. Frequency of inward directed anger was a significant predictor of hair pulling severity even after controlling for psychiatric illness, providing support for the ER model of TTM. These findings underscore the potential importance of understanding and addressing ER in TTM.

The purpose of this study was to determine whether personality prototypes exist among hair pullers and if these groups differ in hair pulling (HP) characteristics, clinical correlates, and quality of life. 164 adult hair pullers completed the NEO-Five Factor Inventory (NEO-FFI; Costa and McCrae, 1992) and self-report measures of HP severity, HP style, affective state, and quality of life. A latent class cluster analysis using NEO-FFI scores was performed to separate participants into clusters. Bonferroni-corrected t-tests were used to compare clusters on HP, affective, and quality of life variables. Multiple regression was used to determine which variables significantly predicted quality of life. Two distinct personality prototypes were identified. Cluster 1 (n=96) had higher neuroticism and lower extraversion, agreeableness, and conscientiousness when compared to cluster 2 (n=68). No significant differences in demographics were reported for the two personality clusters. The clusters differed on extent of focused HP, severity of depression, anxiety, and stress, as well as quality of life. Those in cluster 1 endorsed greater depression, anxiety, and stress, and worse quality of life. Additionally, only depression and cluster membership (based on NEO scores) significantly predicted quality of life.

BACKGROUND Trichotillomania (TTM), obsessive-compulsive disorder (OCD), and skin-picking disorder (SPD) frequently occur together and share overlapping phenomenology, pathophysiology, and possible genetic underpinnings. This study sought to identify factors that predict OCD and SPD in hair pullers. METHODS Five hundred fifty-five adult female hair pullers were recruited from specialty clinics and assessed using standardized, semi-structured interviews and self-reports. Clinical predictors and multivariate models were evaluated using logistic regression modeling. RESULTS Hair pullers met criteria for OCD (18.9%), SPD (19.5%), or chronic skin picking (CSP) (5%), or both comorbid diagnoses, respectively. In the final multivariate model for OCD, family history of OCD and an eating disorder diagnosis were associated with an increased risk of OCD in TTM. A nail-biting diagnosis was associated with a decreased risk of OCD in TTM. In the final multivariate model for SPD/CSP, only family history of OCD was associated with an increased risk of SPD/CSP in TTM. CONCLUSIONS Identification of factors predicting OCD and SPD in TTM provides evidence for the relatedness of these disorders and supports their collective classification as obsessive-compulsive and related disorders (OCRDs) in DSM-5. The findings of this study further underscore the importance of assessing for comorbid OCRDs and family histories of OCRDs in clinical practice.