Snezana Urosevic

Behavioral Approach System and Behavioral Inhibition System sensitivities and bipolar spectrum disorders: prospective prediction of bipolar mood episodes

OBJECTIVES Research has found that bipolar spectrum disorders are associated with Behavioral Approach System (BAS) hypersensitivity and both unipolar and bipolar depression are associated with high Behavioral Inhibition System (BIS) sensitivity, but prospective studies of these relationships are lacking. We tested whether BAS and BIS sensitivities prospectively predicted the time to new onsets of major depressive and hypomanic and manic episodes in bipolar spectrum individuals. METHODS We followed 136 bipolar II or cyclothymic and 157 demographically matched normal control individuals prospectively for an average of 33 months. Participants completed the BIS/BAS scales and symptom measures at Time 1 and semi-structured diagnostic interviews every four months of follow-up. RESULTS The bipolar spectrum group exhibited higher Time 1 BAS, but not BIS, scores than the normal controls, controlling for Time 1 symptoms. Among bipolar spectrum participants, high BAS sensitivity prospectively predicted a shorter time to onset of hypomanic and manic episodes, whereas high BIS sensitivity predicted less survival time to major depressive episodes, controlling for initial symptoms. CONCLUSIONS Consistent with the BAS hypersensitivity model of bipolar disorder, a highly responsive BAS provides vulnerability to onsets of (hypo)manic episodes. In addition, a highly sensitive BIS increases risk for major depressive episodes.

Effect of Bipolar Disorder on Left Frontal Cortical Responses to Goals Differing in Valence and Task Difficulty

BACKGROUND The behavioral activation system (BAS) dysregulation theory of bipolar disorder predicts that bipolar individuals will show an excessive increase in approach motivation during reward striving. Building on past research showing that the left frontal cortical region is involved in approach motivation, we predicted that individuals with bipolar disorder would evidence increased relative left frontal cortical activity in response to goal striving, particularly in response to positive challenges. METHODS Right-handed individuals (age 18-24) with a bipolar spectrum diagnosis (n = 41) and individuals with no major affective psychopathology (n = 53) were presented with cues indicating that, on a given trial, an easy, medium, or hard anagram (scrambled word) would be presented in 7 seconds and that they would receive money or avoid losing money for the correct solution (10 anagrams of each of the 6 types). During this preparation period, electroencephalogram (EEG) alpha power was measured and hemispheric asymmetry indexes were computed. RESULTS Compared with the nonbipolar individuals, individuals with bipolar disorder showed greater relative left frontal cortical activation in preparation for the hard/win trials. Whereas nonbipolar individuals showed a decrease in left frontal cortical activation from medium to hard win trials, bipolar individuals did not. In addition, among bipolar individuals, current self-reported activation related to greater left frontal activation to the hard/win trials. CONCLUSIONS These results provide support for an integrative biopsychosocial model of bipolar disorder, BAS dysregulation theory, and suggest that relative left frontal activity, which may be involved in mania, is triggered by challenging and potentially rewarding events.

Behavioral approach system (BAS)–relevant cognitive styles and bipolar spectrum disorders: Concurrent and prospective associations.

The authors examined concurrent and prospective associations of behavioral approach system (BAS)-relevant and non-BAS-relevant cognitive styles with bipolar spectrum disorders. Controlling for depressive and hypomanic/manic symptoms, 195 individuals with bipolar spectrum disorders scored higher than 194 demographically similar normal controls on BAS sensitivity and BAS-relevant cognitive dimensions of performance concerns, autonomy, and self-criticism, but not on behavioral inhibition system sensitivity and non-BAS-relevant dimensions of approval seeking, sociotropy, and dependency. Moreover, group differences on autonomy fully mediated the association between higher BAS sensitivity and bipolar status. In addition, only BAS-related cognitive dimensions predicted the likelihood of onset of depressive and hypomanic/manic episodes among the bipolar individuals over a 3.2-year follow-up, controlling for initial symptoms and past history of mood episodes. Higher autonomy and self-criticism predicted a greater likelihood of hypomanic/manic episodes, and higher autonomy predicted a lower likelihood of major depressive episodes. In addition, autonomy mediated the associations between BAS sensitivity and prospective hypomanic/manic episodes. These findings suggest that individuals with bipolar spectrum disorders may exhibit a unique profile of BAS-relevant cognitive styles that influence the course of their mood episodes.

Elevated Left Mid-Frontal Cortical Activity Prospectively Predicts Conversion to Bipolar I Disorder

Bipolar disorder is characterized by a hypersensitivity to reward-relevant cues and a propensity to experience an excessive increase in approach-related affect, which may be reflected in hypo/manic symptoms. The present study examined the relationship between relative left-frontal electroencephalographic (EEG) activity, a proposed neurophysiological index of approach-system sensitivity and approach/reward-related affect, and bipolar course and state-related variables. Fifty-eight individuals with cyclothymia or bipolar II disorder and 59 healthy control participants with no affective psychopathology completed resting EEG recordings. Alpha power was obtained and asymmetry indices computed for homologous electrodes. Bipolar spectrum participants were classified as being in a major/minor depressive episode, a hypomanic episode, or a euthymic/remitted state at EEG recording. Participants were then followed prospectively for an average 4.7-year follow-up period with diagnostic interview assessments every 4 months. Sixteen bipolar spectrum participants converted to bipolar I disorder during follow-up. Consistent with hypotheses, elevated relative left-frontal EEG activity at baseline (a) prospectively predicted a greater likelihood of converting from cyclothymia or bipolar II disorder to bipolar I disorder over the 4.7-year follow-up period, (b) was associated with an earlier age-of-onset of first bipolar spectrum episode, and (c) was significantly elevated in bipolar spectrum individuals in a hypomanic episode at EEG recording. This is the first study to our knowledge to identify a neurophysiological marker that prospectively predicts conversion to bipolar I disorder. The fact that unipolar depression is characterized by decreased relative left-frontal EEG activity suggests that unipolar depression and vulnerability to hypo/mania may be characterized by different profiles of frontal EEG asymmetry.

Pubertal status associations with reward and threat sensitivities and subcortical brain volumes during adolescence.

Adolescence is characterized by complex developmental processes that impact behavior, biology, and social functioning. Two such adolescence-specific processes are puberty and increases in reward sensitivity. Relations between these processes are poorly understood. The present study focused on examining unique effects of puberty, age, and sex on reward and threat sensitivities and volumes of subcortical brain structures relevant for reward/threat processing in a healthy sample of 9-18year-olds. Unlike age, pubertal status had a significant unique positive relationship with reward sensitivity. In addition, there was a trend for adolescent females to exhibit higher threat sensitivity with more advanced pubertal development and higher reward and threat sensitivity with older age. Similarly, there were significant puberty by sex interaction effects on striatal volumes, i.e., left nucleus accumbens and right pallidum. The present pattern of results suggests that pubertal development, independent of chronological age, is uniquely associated with reward hypersensitivity and with structural differences in striatal regions implicated in reward processing.

Generation of life events in bipolar spectrum disorders: A re‐examination and extension of the stress generation theory

The extent to which stress generation occurs in bipolar spectrum disorders (BSD) is not well understood. The present study examined whether 75 BSD participants experienced elevated rates of behavior-dependent life events, as compared with 38 normal control participants. Within the BSD group, we also examined whether depressive or hypomanic symptoms prospectively predicted increases in various types of negative and positive life events. Results indicated that BSD participants experienced overall increases in behavior-dependent events over the follow-up, as compared with normal controls. At the symptom level, the event generation process occurred in more specific event domains. Results suggest that the stress generation theory of unipolar depression can be extended to BSD and that the type of generated events may be polarity-specific.

Personality disorder symptom severity predicts onset of mood episodes and conversion to bipolar I disorder in individuals with bipolar spectrum disorder.

Although personality disorders (PDs) are highly comorbid with bipolar spectrum disorders (BSDs), little longitudinal research has been conducted to examine the prospective impact of PD symptoms on the course of BSDs. The aim of this study is to examine whether PD symptom severity predicts shorter time to onset of bipolar mood episodes and conversion to bipolar I disorder over time among individuals with less severe BSDs. Participants (n = 166) with bipolar II disorder, cyclothymia, or bipolar disorder not otherwise specified completed diagnostic interview assessments of PD symptoms and self-report measures of mood symptoms at baseline. They were followed prospectively with diagnostic interviews every 4 months for an average of 3.02 years. Cox proportional hazard regression analyses indicated that overall PD symptom severity significantly predicted shorter time to onset of hypomanic (hazard ratio [HR] = 1.42; p < .001) and major depressive episodes (HR = 1.51; p < .001) and conversion to bipolar I disorder (HR = 2.51; p < .001), after controlling for mood symptoms. Results also suggested that cluster B severity predicted shorter time to onset of hypomanic episodes (HR = 1.38; p = .002) and major depressive episodes (HR = 1.35; p = .01) and conversion to bipolar I disorder (HR = 2.77; p < .001), whereas cluster C severity (HR = 1.56; p < .001) predicted shorter time to onset of major depressive episodes. These results support predisposition models in suggesting that PD symptoms may act as a risk factor for a more severe course of BSDs.