Faculty Bibliography

BACKGROUND: We have recently developed the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (CPFQ), a brief scale to measure cognitive and executive dysfunction in mood and anxiety disorders, and we here report on its reliability and validity. METHODS: The internal consistency of the CPFQ was assessed by computing Cronbach's coefficient alpha based upon the average intercorrelation of the 7 items of the CPFQ in a sample of depressed outpatients and by factor analyzing data from the same sample to confirm that the scale is unifactorial and measuring a single construct. Test-retest reliability of the CPFQ was assessed in a different sample of depressed outpatients by computing Pearson's correlation coefficient between pretreatment screening scores and pretreatment baseline scores. Sensitivity to change of the CPFQ was assessed by computing the dependent t test for the subjects in the active treatment condition in the second sample of depressed outpatients. Finally, convergent validity for the CPFQ was assessed in two different ways. RESULTS: We found that the CPFQ is a unifactorial scale, with strong internal consistency. It has good temporal stability as indicated by high test-retest reliability. The CPFQ was also found to be sensitive to change with treatment and displayed convergent validity by significant correlations with other measures of sleepiness, fatigue, apathy and neuropsychological functioning. Although, as expected, the CPFQ was significantly correlated with a measure of depression, the moderate correlation (r approximately 0.30) indicates that the CPFQ is measuring a different construct. CONCLUSION: In summary, the CPFQ is a unifactorial scale, with strong internal consistency, good temporal stability and sensitivity to change with treatment. Further studies will be needed to assess the validity and reliability of this instrument in other psychiatric and neuropsychiatric conditions associated with cognitive dysfunction.

OBJECTIVE: Anhedonia, the lack of reactivity to pleasurable stimuli, is a cardinal feature of depression that has received renewed interest as a potential endophenotype of this debilitating disease. The goal of the present study was to test the hypothesis that individuals with major depression are characterized by blunted reward responsiveness, particularly when anhedonic symptoms are prominent. METHODS: A probabilistic reward task rooted within signal-detection theory was utilized to objectively assess hedonic capacity in 23 unmedicated subjects meeting DSM-IV criteria for major depressive disorder (MDD) and 25 matched control subjects recruited from the community. Hedonic capacity was defined as reward responsiveness - i.e., the participants' propensity to modulate behavior as a function of reward. RESULTS: Compared to controls, MDD subjects showed significantly reduced reward responsiveness. Trial-by-trial probability analyses revealed that MDD subjects, while responsive to delivery of single rewards, were impaired at integrating reinforcement history over time and expressing a response bias toward a more frequently rewarded cue in the absence of immediate reward. This selective impairment correlated with self-reported anhedonic symptoms, even after considering anxiety symptoms and general distress. CONCLUSIONS: These findings indicate that MDD is characterized by an impaired tendency to modulate behavior as a function of prior reinforcements, and provides initial clues about which aspects of hedonic processing might be dysfunctional in depression.

The structural effects of cocaine on neural systems mediating cognition and motivation are not well known. By comparing the thickness of neocortical and paralimbic brain regions between cocaine-dependent and matched control subjects, we found that four of 18 a priori regions involved with executive regulation of reward and attention were significantly thinner in addicts. Correlations were significant between thinner prefrontal cortex and reduced keypresses during judgment and decision making of relative preference in addicts, suggesting one basis for restricted behavioral repertoires in drug dependence. Reduced effortful attention performance in addicts also correlated with thinner paralimbic cortices. Some thickness differences in addicts were correlated with cocaine use independent of nicotine and alcohol, but addicts also showed diminished thickness heterogeneity and altered hemispheric thickness asymmetry. These observations suggest that brain structure abnormalities in addicts are related in part to drug use and in part to predisposition toward addiction.

BACKGROUND: Bipolar disorder (BPD) features cycling mood states ranging from depression to mania with intermittent phases of euthymia. Bipolar disorder subjects often show excessive goal-directed and pleasure-seeking behavior during manic episodes and reduced hedonic capacity during depressive episodes, indicating that BPD might involve altered reward processing. Our goal was to test the hypothesis that BPD is characterized by impairments in adjusting behavior as a function of prior reinforcement history, particularly in the presence of residual anhedonic symptoms. METHODS: Eighteen medicated BPD subjects and 25 demographically matched comparison subjects performed a probabilistic reward task. To identify putative dysfunctions in reward processing irrespective of mood state, primary analyses focused on euthymic BPD subjects (n = 13). With signal-detection methodologies, response bias toward a more frequently rewarded stimulus was used to objectively assess the participants' propensity to modulate behavior as a function of reinforcement history. RESULTS: Relative to comparison subjects, euthymic BPD subjects showed a reduced and delayed acquisition of response bias toward the more frequently rewarded stimulus, which was partially due to increased sensitivity to single rewards of the disadvantageous stimulus. Analyses considering the entire BPD sample revealed that reduced reward learning correlated with self-reported anhedonic symptoms, even after adjusting for residual manic and anxious symptoms and general distress. CONCLUSIONS: The present study provides preliminary evidence indicating that BPD, even during euthymic states, is characterized by dysfunctional reward learning in situations requiring integration of reinforcement information over time and thus offers initial insights about the potential source of dysfunctional reward processing in this disorder.

OBJECTIVE: We examined the relationship between mood symptoms and episodes in patients with bipolar disorder and burden reported by their primary caregivers. METHOD: Data on subjective and objective burden reported by 500 primary caregivers for 500 patients with bipolar disorder participating in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) were collected using semistructured interviews. Patient data were collected prospectively over 1 year. The relationship between patient course and subsequent caregiver burden was examined. RESULTS: Episodes of patient depression, but not mood elevation, were associated with greater objective and subjective caregiver burden. Burden was associated with fewer patient days well over the previous year. Patient depression was associated with caregiver burden even after controlling for days well. CONCLUSION: Patient depression, after accounting for chronicity of symptoms, independently predicts caregiver burden. This study underscores the important impact of bipolar depression on those most closely involved with those whom it affects.

BACKGROUND: Low cerebral bioenergetic metabolism has been reported in subjects with major depressive disorder (MDD). Thyroid hormones have been shown to increase brain bioenergetic metabolism. We assessed whether changes in brain bioenergetics measured with phosphorus magnetic resonance spectroscopy ((31)P MRS) correlate with treatment outcome during augmentation treatment with triiodothyronine (T3) in MDD. METHODS: Nineteen subjects meeting DSM-IV criteria for MDD who had previously failed to respond to selective serotonin reuptake inhibitor (SSRI) antidepressant drugs received open label and prospective augmentation treatment with T3 for 4 weeks. We obtained (31)P MRS spectra before and after treatment from all MDD subjects and baseline (31)P MRS from nine normal control subjects matched for age and gender. RESULTS: At baseline, depressed subjects had lower intracellular Mg(2+) compared with control subjects. Seven MDD subjects (38.9%) were treatment responders (>or= 50% improvement). Total nucleoside triphosphate (NTP), which primarily represents adenosine triphosphate (ATP), increased significantly in MDD subjects responding to T3 augmentation compared with treatment nonresponders. Phosphocreatine, which has a buffer role for ATP, decreased in treatment responders compared with nonresponders. CONCLUSIONS: The antidepressant effect of thyroid hormone (T3) augmentation of SSRIs is correlated with significant changes in the brain bioenergetic metabolism. This seems to be a re-normalization of brain bioenergetics in treatment responders. Further studies will determine whether these findings can be generalized to other antidepressant treatments.

OBJECTIVE: We investigated frontal quantitative EEG (QEEG) as predictor of changes in suicidal ideation (SI) during SSRI treatment in major depressive disorder (MDD). METHOD: Eighty-two subjects meeting DSM-IV criteria for MDD entered an 8-week, prospective, open-label treatment with flexible dose SSRIs and completed at least 4 weeks of treatment. We assessed MDD severity with the 17-item Hamilton Depression Rating Scale (HAM-D-17); change in SI was measured with HAM-D item no. 3. We recorded four-channel EEGs (F7-Fpz, F8-Fpz, A1-Fpz, A2-Fpz) before treatment. RESULTS: During the first 4 weeks of treatment 9 (11%) subjects experienced worsening SI. Left-right asymmetry of combined theta + alpha power correlated significantly with change in SI from baseline, even when adjusting for changes in depression severity (HAM-D-17) and for the SSRI utilized. CONCLUSION: Frontal QEEG parameters before treatment may predict worsening SI during SSRI treatment in MDD.

Selecting the most effective antidepressant for depressed subjects having failed previous treatments is difficult; the rates of success are relatively low. There is a clear need for objective biomarkers which could assist and optimize such treatment selection. We review here the current literature and recent developments on the role of quantitative EEG (QEEG) predictors of treatment outcome in major depressive disorder.

The authors conducted exploratory analyses to determine whether specific symptoms of major depressive disorder (MDD) are associated with cardiac disease in 4,041 outpatients at baseline in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. MDD was diagnosed with the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition; depressive symptoms were evaluated with the 30-item Inventory of Depressive Symptomatology, Clinician-Rated; and cardiac disease, with the Cumulative Illness Rating Scale. After adjustments for gender, age, ethnicity, education, and employment status, sympathetic arousal and early-morning insomnia were significantly associated with cardiac disease. Prospective studies are warranted to confirm these results.