El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This letter has the purpose to comment the article by Marwaha et al. regarding affective instability and mental disorders. We wish to highlight the importance to report the proper measures of association in case-control studies, and the impact of adjusting the results when finding associations with possible confounders in the bivariate analysis. / Revisión por pares / Revisión por pares

The National Institute of Mental Health’s (NIMH) Research Domain Criteria (RDoC; Insel et al., 2010; Sanislow et al., 2010) were established in an effort to explore underlying dimensions that cut across many existing disorders as well as to provide an alternative to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5; APA, 2013). The present dissertation aimed to study one major component of the RDoC model, negative valence, as compared to other models hypothesized to be closely related, as well as its relationship to a key component of psychopathology, affective instability. Participants were adult community residents (N=90) currently in mental health treatment. Participants received self-report measures of RDoC negative valence, five-factor model (FFM) neuroticism, and DSM-5 Section 3 negative affectivity, along with measures of affective instability, borderline personality disorder, and social-occupational impairment. Through this investigation, a better understanding and potential expansion of this new model of diagnosis for clinicians and researchers is provided. In particular, it is suggested that RDoC negative valence is commensurate with FFM neuroticism and DSM-5 negative affectivity, and it would be beneficial if it was expanded to include affective instability.

Substance use disorders (SUDs) are a growing concern in today’s society. Substantial research has advanced our understanding of how cognitive control, reward processing, and emotional difficulties may contribute to the development and maintenance of SUDs; however, the impact of affective instability in SUDs has received limited attention. I sought to examine how different dimensions of affective instability interact to increase substance misuse, and to investigate the impact of affective instability and substance use on neural mechanisms of reward and emotion processing. Specifically, I was interested in two event-related potential (ERP) components, the reward positivity and the late positive potential (LPP), which respectively reflect the neural mechanisms of reward and emotion processing. Toward this end, I recorded the ongoing electroencephalogram (EEG) from undergraduate students as they navigated two T-maze tasks in search of rewards. Further, one of the tasks included neutral, pleasant, and unpleasant pictures from the International Affective Picture System (IAPS). Participants also completed several questionnaires pertaining to substance use and personality. A principal components analysis (PCA) revealed a factor related to affective instability, which I named reactivity. This factor significantly predicted increased substance use. Interestingly, individuals reporting higher levels of affective reactivity also displayed a larger reward positivity following stimuli with emotional content. The current study identified a group of high-risk substance users characterized by greater levels of affective reactivity and increased reward processing. It is my hope that these results further elucidate the complexities of SUDs and help to create efficacious, individually-tailored treatment programs for those struggling with SUDs. / Graduate

Actuellement, le diagnostic différentiel du trouble bipolaire (TB) et du trouble de personnalité limite (TPL) à l’adolescence s’avère difficile et complique le choix thérapeutique. Portant sur le TB et le TPL, ce mémoire fait le point sur la littérature scientifique adulte et adolescente, vérifie la faisabilité et présente les résultats d’une étude exploratoire portant sur les variables cliniques (instabilité émotionnelle, hostilité, impulsivité, tempraément) et le rythme veille-sommeil à l’adolescence. L’étude exploratoire comprend sept adolescents TB et huit TPL (12-17 ans), évalués par questionnaires autoadministrés pour les variables cliniques, et par actigraphie et agenda de sommeil pour le rythme veille-sommeil. Aucune différence significative n’existe entre les deux troubles pour les variables cliniques. En moyenne, les adolescents TB ont porté l'actigraphie pendant 9,9 jours et ont rempli un agenda de sommeil pendant 5,7 jours; chez les TPL, les chiffres sont respectivement 9,8 et 8,9 jours. Comparés aux TPL, les TB ont un plus grand intervalle d’éveil (p=0,035), ont un plus grand intervalle de sommeil (p>0,05), et ont une plus grand variabilité intrajournalière (p=0,04). Les données subjectives (agenda de sommeil) semblent refléter les données objectives (actigraphie) : aucune différence statistique n’est observée entre les deux mesures pour le délai d’endormissement, la durée du dernier réveil et le temps total de sommeil. La recension de la littérature montre un manque de données chez l’adolescent quant aux deux troubles. La faisabilité de l’étude est démontrée par la présence de résultats analysables. Ceci encourage la poursuite des recherches sur ces variables, afin de distinguer les deux psychopathologies à l’adolescence. / Presently, differential diagnosis between bipolar disorder (BD) and borderline personality disorder (BPD) in adolescents remains difficult and affects therapeutic choices. This master’s thesis reviews current scientific literature, both in adults and adolescents. It examines feasibility and presents results of a study on clinical dimensions and endophenotypes in adolescent BD and BPD. Seven BD and eight BPD adolescents (12-17 years old) were evaluated by self-reported questionnaires for clinical variables (affective instability, impulsivity, hostility and temperament) and by actigraphy and sleep diary for sleep-wake circadian rhythm. No significant difference was found between BD and BPD for the clinical variables. BD adolescents wore actigraphic device for 9.9 days and completed the sleep diary for 5.7 days on average; for BPD subjects, the numbers were respectively 9.8 days and 8.9 days. Compared to BPD, BD patients had longer active interval (p=0.035), tended to sleep longer, and had more intradaily variability (p=0.04). Subjective data (sleep diary) and objective data (actigraphy) did not significantly differ on sleep onset latency, last awakening duration and total sleep time, which suggested that BD and BPD adolescents had a good estimate of their sleep patterns. Literature review showed a dearth of research done on adolescent BD and BPD. Feasibility of this study was verified, since data was successfully collected. Research on these variables should continue, so differential diagnosis can be done in adolescent BD and BPD.

Actuellement, le diagnostic différentiel du trouble bipolaire (TB) et du trouble de personnalité limite (TPL) à l’adolescence s’avère difficile et complique le choix thérapeutique. Portant sur le TB et le TPL, ce mémoire fait le point sur la littérature scientifique adulte et adolescente, vérifie la faisabilité et présente les résultats d’une étude exploratoire portant sur les variables cliniques (instabilité émotionnelle, hostilité, impulsivité, tempraément) et le rythme veille-sommeil à l’adolescence. L’étude exploratoire comprend sept adolescents TB et huit TPL (12-17 ans), évalués par questionnaires autoadministrés pour les variables cliniques, et par actigraphie et agenda de sommeil pour le rythme veille-sommeil. Aucune différence significative n’existe entre les deux troubles pour les variables cliniques. En moyenne, les adolescents TB ont porté l'actigraphie pendant 9,9 jours et ont rempli un agenda de sommeil pendant 5,7 jours; chez les TPL, les chiffres sont respectivement 9,8 et 8,9 jours. Comparés aux TPL, les TB ont un plus grand intervalle d’éveil (p=0,035), ont un plus grand intervalle de sommeil (p>0,05), et ont une plus grand variabilité intrajournalière (p=0,04). Les données subjectives (agenda de sommeil) semblent refléter les données objectives (actigraphie) : aucune différence statistique n’est observée entre les deux mesures pour le délai d’endormissement, la durée du dernier réveil et le temps total de sommeil. La recension de la littérature montre un manque de données chez l’adolescent quant aux deux troubles. La faisabilité de l’étude est démontrée par la présence de résultats analysables. Ceci encourage la poursuite des recherches sur ces variables, afin de distinguer les deux psychopathologies à l’adolescence. / Presently, differential diagnosis between bipolar disorder (BD) and borderline personality disorder (BPD) in adolescents remains difficult and affects therapeutic choices. This master’s thesis reviews current scientific literature, both in adults and adolescents. It examines feasibility and presents results of a study on clinical dimensions and endophenotypes in adolescent BD and BPD. Seven BD and eight BPD adolescents (12-17 years old) were evaluated by self-reported questionnaires for clinical variables (affective instability, impulsivity, hostility and temperament) and by actigraphy and sleep diary for sleep-wake circadian rhythm. No significant difference was found between BD and BPD for the clinical variables. BD adolescents wore actigraphic device for 9.9 days and completed the sleep diary for 5.7 days on average; for BPD subjects, the numbers were respectively 9.8 days and 8.9 days. Compared to BPD, BD patients had longer active interval (p=0.035), tended to sleep longer, and had more intradaily variability (p=0.04). Subjective data (sleep diary) and objective data (actigraphy) did not significantly differ on sleep onset latency, last awakening duration and total sleep time, which suggested that BD and BPD adolescents had a good estimate of their sleep patterns. Literature review showed a dearth of research done on adolescent BD and BPD. Feasibility of this study was verified, since data was successfully collected. Research on these variables should continue, so differential diagnosis can be done in adolescent BD and BPD.