Biomedical subjects

Andrew J Tomarken

Publications and source records attributed to Andrew J Tomarken.

7 recordsLinked to original sources

PubMed2005

Do venlafaxine XR and paroxetine equally influence negative and positive affect?

BACKGROUND: We assessed the therapeutic effects of venlafaxine XR and paroxetine on mood and anxiety symptoms derived from the tripartite model of mood. We hypothesized that the two antidepressants would have largely similar effects on symptoms of negative affect because both agents influence serotonergic systems. However, based on evidence indicating linkages between catecholaminergic activity and the emotional dimension of positive affect, we hypothesized that the catecholaminergic effects of venlafaxine XR would yield particularly pronounced effects on symptoms of positive affect. METHODS: Twenty depressed outpatients were randomly assigned to treatment with either venlafaxine XR (225 mg/day) or paroxetine (30 mg/day) during a 12-week treatment trial. Weekly mood ratings were collected using the Mood and Anxiety Symptom Questionnaire [Watson, D., Clark, L.A., Weber, K., Assenheimer, J.S., Strauss, M.E., McCormick, R.A., 1995. Testing a tripartite model: II. Exploring the symptom structure of anxiety and depression in student, adult, and patient samples. J. Abnorm. Psychol. 104 (1), 15-25] [Watson, D., Weber, K., Assenheimer, J.S., Clark, L.A., Strauss, M.E., McCormick, R.A., 1995. Testing a tripartite model: I. Evaluating the convergent and discriminant validity of anxiety and depression symptom scales. J. Abnorm. Psychol. 104 (1), 3-14]. RESULTS: Consistent with predictions, analyses revealed that there were no significant differences between venlafaxine XR and paroxetine on measures of negative affect. However, contrary to predictions, the two medications produced similar changes on measures of positive affect. LIMITATIONS: Replication and extension using a larger sample size are mandated. CONCLUSIONS: These preliminary results suggest that two antidepressants that appear to have dissimilar mechanisms of action may nevertheless have similar effects on the positive and negative affective components of depression. Alternatively, paroxetine may have a clinically relevant noradrenergic effect at the dose tested.

Adult↗

PubMed2004

Resting frontal brain activity: linkages to maternal depression and socio-economic status among adolescents.

We tested the prediction that resting frontal brain asymmetry would be a marker of vulnerability for depression among adolescents. Baseline electroencephalographic (EEG) activity was recorded from 12 to 14-year-old adolescents whose mothers had a history of depression (high risk group) and whose mothers were lifetime-free of axis I psychopathology (low risk group). High risk adolescents demonstrated the hypothesized pattern of relative left frontal hypo-activity on alpha-band measures. Such effects were specific to the mid-frontal region and generally consistent across reference montages. Socio-economic status (SES) also predicted alpha asymmetry. When the effects of SES and risk status were jointly assessed, SES contributed unique variance to the prediction of frontal brain asymmetry. The implications of the observed relations among maternal depression, SES, and frontal brain asymmetry are discussed.

Adolescent↗

PubMed2004

Assessing the effects of bupropion SR on mood dimensions of depression.

BACKGROUND: We assessed the therapeutic effects of bupropion SR and placebo on mood and anxiety symptoms derived from the tripartite model of mood. Based on evidence indicating linkages between dopaminergic activity and the emotional dimension of positive affect/anhedonia, we hypothesized that the dopaminergic effects of bupropion SR would yield particularly pronounced effects on symptoms of anhedonia, relative to anxiety. METHODS: Nineteen depressed outpatients were randomly assigned to treatment with either bupropion SR 300 mg/day or placebo during a 6-week initial treatment phase. This was followed by a second open-label phase in which patients previously treated with bupropion SR had their dose increased to 400 mg/day, and the placebo group was initiated on bupropion SR 300 mg/day. RESULTS: Random regression analyses revealed that during the initial double-blind phase, bupropion SR elicited greater declines than placebo on all measures except those that assessed anxiety. By contrast, the weakest placebo effects were evident on anhedonia. Items assessing the low positive affect pole of the anhedonia dimension were more sensitive to earlier/lower dose bupropion SR treatment, whereas items assessing the high positive affect pole were more sensitive to later/higher dose bupropion SR treatment. LIMITATIONS: Replication and extension using a larger sample size are mandated. CONCLUSIONS: This study suggests that the catecholaminergic effects of bupropion SR tended to produce more robust effects on anhedonia/positive affect than placebo.

Administration, Oral↗

PubMed2004

Early- and late-onset startle modulation in unipolar depression.

In two experimental sessions, we assessed early- and late-onset acoustic startle eyeblink modulation and subjective ratings of emotional pictures by nondepressed participants and by unipolar depressed participants. Depressed participants were assessed before and after treatment with the antidepressant medication Bupropion SR. Both depressed and nondepressed participants exhibited arousal-dependent startle modulation to early probes occurring 300 ms after picture onset. Nondepressed participants demonstrated the expected valence-dependent startle modulation to late probes (3,500-4,500 ms post-onset). In contrast, the late-probe blink magnitudes of depressed patients were unrelated to picture valence. This pattern of group differences was not moderated by treatment. There were no between-group differences in self-report ratings to pictures. These results suggest that depression may be characterized by anomalous responses to affective stimuli and that startle modulation can be a more sensitive index of affective response deficits linked to depression than self-report measures.

Adult↗

PubMed2003

Introduction to the special section on structural equation modeling.

Structural equation modeling (SEM) is a frequently used data-analytic technique in psychopathology research. This popularity is due to the unique capabilities and broad applicability of SEM and to recent advances in model and software development. Unfortunately, the popularity and accessibility of SEM is matched by its complexities and ambiguities. Thus, users are often faced with difficult decisions regarding a variety of issues. This special section is designed to increase the effective use of SEM by reviewing recently developed modeling capabilities, identifying common problems in application, and recommending appropriate strategies for analysis and evaluation.

Humans↗

PubMed2003

Potential problems with "well fitting" models.

The assessment of model fit is a more complex and indeterminate process than is commonly acknowledged by researchers who use structural equation modeling (SEM) techniques. Even models that are well fitting according to commonly used statistical tests and descriptive fit indices can have significant problems and ambiguities. The authors discuss 7 potential difficulties that can arise and that should temper researchers' conclusions: equivalent models, nonequivalent but well-fitting alternative models, omitted variables, problematic lower-order model components, the failure to parse composite models into meaningful partitions (e.g., measurement vs. structural), inattention to the multiple factors that affect the sensitivity of measures of fit to model misspecifications, and reliance on specification searches. In addition to providing examples of each of these problems, the authors offer recommendations for psychopathologists who conduct SEM analyses.

Analysis of Variance↗

PubMed2002

Startle modulation before, during and after exposure to emotional stimuli.

Although affective modulation of the startle reflex is a highly replicable effect, the majority of studies have administered startle probes during exposure to affective stimuli. To examine more comprehensively the temporal course of startle potentiation, we assessed blink modulation before, during and immediately after exposure to positive, negative and neutral pictures. During each trial, cues about the affective content of pictures were presented, after which acoustic startle probes were delivered either before picture onset, during picture onset or immediately after picture offset. As expected, we observed a linear relation between picture valence and startle amplitude during picture viewing. Surprisingly, startle amplitude was larger while anticipating pleasant and unpleasant pictures relative to neutral pictures. No significant effects were observed during the offset phase. These results indicate that startle modulation is conditional upon temporal factors linked to stimulus onset and offset.

Adolescent↗