Combining a dopamine agonist and selective serotonin reuptake inhibitor for the treatment of depression: a double-blind, randomized pilot study.

BACKGROUND: Antidepressants that act on two or more amine neurotransmitters may confer higher remission rates when first-line agents affecting a single neurotransmitter have failed. Pramipexole, a dopamine agonist, has antidepressant effects in patients with major depressive disorder (MDD). This pilot study examined the efficacy and safety of combination therapy with pramipexole and the selective serotonin reuptake inhibitor (SSRI) escitalopram in MDD. METHODS: In this double-blind, controlled, pilot study, 39 patients with DSM-IV MDD who had failed to respond to a standard antidepressant treatment trial were randomized to receive pramipexole (n=13), escitalopram (n=13), or their combination (n=13) for six weeks. Pramipexole was started at 0.375 mg/day and titrated weekly up to 2.25 mg/day; escitalopram dosage remained at 10 mg/day. The primary outcome measure was the Montgomery-Asberg Depression Rating Scale (MADRS). RESULTS: Subjects receiving pramipexole monotherapy had significantly lower MADRS scores than the combination group (p=0.01); no other primary drug comparisons were significant. The combination group had a substantially higher dropout rate than the escitalopram and pramipexole groups (69%, 15%, 15%, respectively). Only 15% of patients in the combination group tolerated regularly scheduled increases of pramipexole throughout the study, compared with 46% of patients in the pramipexole group. LIMITATIONS: Group size was small and the treatment phase lasted for only six weeks. CONCLUSIONS: The combination of an SSRI and a dopamine agonist was not more effective than either agent alone, nor did it produce a more rapid onset of antidepressant action. Combination therapy with escitalopram and pramipexole may not be well-tolerated.

Abnormal function of monoamine oxidase-A in comorbid major depressive disorder and cardiovascular disease: pathophysiological and therapeutic implications (review).

The association between major depressive disorder (MDD) and cardiovascular disease (CVD) is among the best described medical comorbidities. The presence of MDD increases the risk of cardiac admissions and mortality and increases healthcare costs in patients with CVD, and similarly, CVD affects the course and outcome of MDD. The potential shared biological mechanisms involved in these comorbid conditions are not well known. However, the enzyme monoamine oxidase-A (MAO-A), which has a key role in the degradation of catecholamines, has been associated with the pathophysiology and therapeutics of both MDD and CVD. Increased MAO-A activity results in the dysregulation of downstream targets of this enzyme and thus affects the pathophysiology of the two diseases. These deleterious effects include altered noradrenaline turnover, with a direct elevation in oxidative stress parameters, as well as increased platelet activity and cytokine levels. These effects were shown to be reversed by MAO inhibitors. Here, a model describing a key role for the MAO-A in comorbid MDD and CVD is proposed, with focus on the shared pathophysiological mechanisms and the potential therapeutic relevance of agents targeting this enzyme.

Population-based input function and image-derived input function for [¹¹C](R)-rolipram PET imaging: methodology, validation and application to the study of major depressive disorder.

UNLABELLED: Quantitative PET studies of neuroreceptor tracers typically require that arterial input function be measured. The aim of this study was to explore the use of a population-based input function (PBIF) and an image-derived input function (IDIF) for [(11)C](R)-rolipram kinetic analysis, with the goal of reducing - and possibly eliminating - the number of arterial blood samples needed to measure parent radioligand concentrations. METHODS: A PBIF was first generated using [(11)C](R)-rolipram parent time-activity curves from 12 healthy volunteers (Group 1). Both invasive (blood samples) and non-invasive (body weight, body surface area, and lean body mass) scaling methods for PBIF were tested. The scaling method that gave the best estimate of the Logan-V(T) values was then used to determine the test-retest variability of PBIF in Group 1 and then prospectively applied to another population of 25 healthy subjects (Group 2), as well as to a population of 26 patients with major depressive disorder (Group 3). Results were also compared to those obtained with an image-derived input function (IDIF) from the internal carotid artery. In some subjects, we measured arteriovenous differences in [(11)C](R)-rolipram concentration to see whether venous samples could be used instead of arterial samples. Finally, we assessed the ability of IDIF and PBIF to discriminate depressed patients (MDD) and healthy subjects. RESULTS: Arterial blood-scaled PBIF gave better results than any non-invasive scaling technique. Excellent results were obtained when the blood-scaled PBIF was prospectively applied to the subjects in Group 2 (V(T) ratio 1.02±0.05; mean±SD) and Group 3 (V(T) ratio 1.03±0.04). Equally accurate results were obtained for two subpopulations of subjects drawn from Groups 2 and 3 who had very differently shaped (i.e. "flatter" or "steeper") input functions compared to PBIF (V(T) ratio 1.07±0.04 and 0.99±0.04, respectively). Results obtained via PBIF were equivalent to those obtained via IDIF (V(T) ratio 0.99±0.05 and 1.00±0.04 for healthy subjects and MDD patients, respectively). Retest variability of PBIF was equivalent to that obtained with full input function and IDIF (14.5%, 15.2%, and 14.1%, respectively). Due to [(11)C](R)-rolipram arteriovenous differences, venous samples could not be substituted for arterial samples. With both IDIF and PBIF, depressed patients had a 20% reduction in [(11)C](R)-rolipram binding as compared to control (two-way ANOVA: p=0.008 and 0.005, respectively). These results were almost equivalent to those obtained using 23 arterial samples. CONCLUSION: Although some arterial samples are still necessary, both PBIF and IDIF are accurate and precise alternatives to full arterial input function for [(11)C](R)-rolipram PET studies. Both techniques give accurate results with low variability, even for clinically different groups of subjects and those with very differently shaped input functions.

Downregulation of brain phosphodiesterase type IV measured with 11C-(R)-rolipram positron emission tomography in major depressive disorder.

BACKGROUND: Phosphodiesterase type IV (PDE4), an important component of the cyclic adenosine monophosphate (cAMP) cascade, selectively metabolizes cAMP in the brain to the inactive monophosphate. Basic studies suggest that PDE4 mediates the effects of several antidepressants. This study sought to quantify the binding of 11C-(R)-rolipram, a PDE4 inhibitor, as an indirect measure of this enzyme's activity in the brain of individuals with major depressive disorder (MDD) compared with healthy control subjects. METHODS: 11C-(R)-Rolipram brain positron emission tomography scans were performed in 28 unmedicated MDD subjects and 25 age- and gender-matched healthy control subjects. Patients were moderately depressed and about one half were treatment-naive. 11C-(R)-Rolipram binding in the brain was measured using arterial 11C-(R)-rolipram levels to correct for the influence of cerebral blood flow. RESULTS: Major depressive disorder subjects showed a widespread, approximately 20% reduction in 11C-(R)-rolipram binding (p = .002), which was not caused by different volumes of gray matter. Decreased rolipram binding of similar magnitudes was observed in most brain areas. Rolipram binding did not correlate with the severity of depressive or anxiety symptoms. CONCLUSIONS: This study is the first to demonstrate that brain levels of PDE4, a critical enzyme that regulates cAMP, are decreased in unmedicated individuals with MDD in vivo. These results are in line with human postmortem and rodent studies demonstrating downregulation of the cAMP cascade in MDD and support the hypothesis that agents such as PDE4 inhibitors, which increase activity within the cAMP cascade, may have antidepressant effects.

Rapid decrease in depressive symptoms with an N-methyl-d-aspartate antagonist in ECT-resistant major depression.

BACKGROUND: Ketamine rapidly improves depressive symptoms in patients with treatment-resistant major depressive disorder (MDD) who do not respond to multiple standard antidepressants. However, it remains unknown whether ketamine is equally effective in patients with MDD who previously also did not respond to electroconvulsive therapy (ECT). METHODS: This study compared 17 patients with treatment-resistant MDD who previously did not respond to ECT and 23 patients with treatment-resistant MDD who had not previously received ECT. All subjects received a single open-label infusion of ketamine (0.5 mg/kg). Patients were evaluated using the Montgomery-Asberg Depression Rating Scale (MADRS) at baseline (60 min before the infusion), as well as at 40, 80, 120, and 230 min after infusion. RESULTS: Depressive symptoms were significantly improved in the ECT-resistant group at 230 minutes with a moderate effect size (p < .001, d = 0.50, 95% C.I.: 0.21-0.80). At 230 minutes, the non-ECT exposed group showed significant improvement with a large effect size (p < .001, d=1.00, 95% C.I.: 0.71-1.29). CONCLUSION: Ketamine appears to improve depressive symptoms in patients with MDD who had previously not responded to ECT. These preliminary results encourage further investigation with a larger sample size to determine effectiveness compared to other treatment-resistant patients with MDD.

Revisiting the effectiveness of standard antidepressants in bipolar disorder: are monoamine oxidase inhibitors superior?

OBJECTIVE: The role of antidepressants in treating bipolar disorder is controversial, and the comparative effectiveness of specific drugs is insufficiently studied.We report here a comparison of monoamine oxidase inhibitors (MAOIs) with the serotonin reuptake inhibitor paroxetine (PAROX). EXPERIMENTAL DESIGN: We conducted a retrospective analysis of data from a larger study, using the first antidepressant trial administered either after entry (n = 46) or after a recurrent episode during study participation (n = 6).Twenty two patients were treated with PAROX and 30 with an MAOI. Durable recovery was determined from Hamilton depression and Young mania scores, based on published criteria. PRINCIPAL OBSERVATIONS: PAROX treatment led to durable recovery in 27% of patients, a result very similar to the 24% recovery rate found in a recent STEP-BD trial. In contrast, patients treated with an MAOI had a 53% durable recovery rate. Survival analysis showed a significantly faster onset of durable recovery with MAOIs (x2 = 4.77, p = 0.029). Among subjects who were able to complete an adequate treatment trial of at least four weeks duration, durable recovery was attained in a significantly greater proportion of those treated with an MAOI (16 of 23, 70%) as compared to PAROX (6 of 18, 33%)(Fisher's Exact Test, p = 0.023). CONCLUSIONS: In these patients with bipolar depression, the antidepressant effectiveness of PAROX was unacceptably low, but rates of recovery with MAOIs were significantly higher.

Orbitofrontal cortex gray matter volumes in bipolar disorder patients: a region-of-interest MRI study.

OBJECTIVES: Functional and postmortem studies suggest that the orbitofrontal cortex (OFC) is involved in the pathophysiology of bipolar disorder (BD). This anatomical magnetic resonance imaging (MRI) study examined whether BD patients have smaller OFC gray matter volumes compared to healthy comparison subjects (HC). METHODS: Twenty-eight BD patients were compared to 28 age- and gender-matched HC. Subjects underwent a 1.5T MRI with 3D spoiled gradient recalled acquisition. Total OFC and medial and lateral subdivisions were manually traced by a blinded examiner. Images were segmented and gray matter volumes were calculated using an automated method. RESULTS: Analysis of covariance, with intracranial volume as covariate, showed that BD patients and HC did not differ in gray matter volumes of total OFC or its subdivisions. However, total OFC gray matter volume was significantly smaller in depressed patients (n = 10) compared to euthymic patients (n = 18). Moreover, total OFC gray matter volumes were inversely correlated with depressive symptom intensity, as assessed by the Hamilton Depression Rating Scale. OFC gray matter volumes were not related to lithium treatment, age at disease onset, number of episodes, or family history of mood disorders. CONCLUSIONS: Our results suggest that abnormal OFC gray matter volumes are not a pervasive characteristic of BD, but may be associated with specific clinical features of the disorder.

The role of interpersonal and social rhythm therapy in improving occupational functioning in patients with bipolar I disorder.

OBJECTIVE: Recent studies demonstrate the poor psychosocial outcomes associated with bipolar disorder. Occupational functioning, a key indicator of psychosocial disability, is often severely affected by the disorder. The authors describe the effect of acute treatment with interpersonal and social rhythm therapy on occupational functioning over a period of approximately 2.5 years. METHOD: Patients with bipolar I disorder were randomly assigned to receive either acute and maintenance interpersonal and social rhythm therapy, acute and maintenance intensive clinical management, acute interpersonal and social rhythm therapy and maintenance intensive clinical management, or acute intensive clinical management and maintenance interpersonal and social rhythm therapy, all with appropriate pharmacotherapy. Occupational functioning was measured with the UCLA Social Attainment Scale at baseline, at the end of acute treatment, and after 1 and 2 years of maintenance treatment. RESULTS: The main effect of treatment did not reach conventional levels of statistical significance; however, the authors observed a significant time by initial treatment interaction. Participants initially assigned to interpersonal and social rhythm therapy showed more rapid improvement in occupational functioning than those initially assigned to intensive clinical management, primarily accounted for by greater improvement in occupational functioning during the acute treatment phase. At the end of 2 years of maintenance treatment, there were no differences between the treatment groups. A gender effect was also observed, with women who initially received interpersonal and social rhythm therapy showing more marked and rapid improvement. There was no effect of maintenance treatment assignment on occupational functioning outcomes. CONCLUSIONS: In this study, interpersonal and social rhythm therapy, with its emphasis on amelioration of interpersonal and role functioning, improved occupational functioning significantly more rapidly than did a psychoeducational and supportive approach with no such emphasis on functional capacities.

Which symptoms predict recurrence of depression in women treated with maintenance interpersonal psychotherapy?

BACKGROUND: Even low levels of residual symptoms are known to increase the risk of relapse and early recurrence of major depression. It is not known if ongoing psychotherapy lessens this risk. We therefore examined the impact of persistent symptoms, including mood, insomnia, and anxiety symptoms, on time to recurrence in women receiving maintenance interpersonal psychotherapy (IPT-M) for recurrent depression. METHODS: We analyzed data on 131 women aged 20-60 from a 2-year randomized trial of weekly versus twice-monthly versus monthly IPT-M. Participants achieved remission with IPT alone (n=99) or IPT plus sequential antidepressant medication (n=32). Medications were tapered before starting maintenance treatment. Residual symptoms were assessed with the Hamilton Rating Scale for Depression (HRSD; total score and subscales); insomnia was also assessed in 76 women with the Pittsburgh Sleep Quality Index (PSQI). Data analyses used Cox proportional hazards regression models. RESULTS: Neither overall burden of residual symptoms (HRSD total score), nor HRSD mood and anxiety subscale scores predicted recurrence during ongoing IPT-M. In contrast, persistent insomnia measured both by the HRSD-17 insomnia subscale and the PSQI predicted recurrence. Women with persistent insomnia who required sequential pharamacotherapy had the highest recurrence rate (65%) compared to women requiring sequential treatment without insomnia (13%), or women who had recovered with IPT alone but had persistent insomnia (21%) or no insomnia (18%). CONCLUSIONS: Persistent insomnia following the recovery from an episode of recurrent major depression is associated with increased risk of recurrence despite maintenance psychotherapy, particularly for those withdrawn from antidepressant medication.

Illness duration and total brain gray matter in bipolar disorder: evidence for neurodegeneration?

Previous studies have suggested that bipolar disorder (BD) is associated with alterations in neuronal plasticity, but the effects of the progression of illness on brain anatomy have been poorly investigated. We studied the correlation between length of illness, age, age at onset, and the number of previous episodes and total brain, total gray, and total white matter volumes in BD, unipolar (UP) and healthy control (HC) subjects. Thirty-six BD, 31 UP and 55 HCs underwent a 1.5 T brain magnetic resonance imaging scan, and gray and white matter volumes were manually traced blinded to the subjects' diagnosis. Partial correlation analysis showed that length of illness was inversely correlated with total gray matter volume after adjusting for total intracranial volume in BD (r(p)= -0.51; p=0.003) but not in UP subjects (r(p)= -0.23; p=0.21). Age at illness onset and the number of previous episodes were not significantly correlated with gray matter volumes in BD or UP subjects. No significant correlation with total white matter volume was observed. These results suggest that the progression of illness may be associated with abnormal cellular plasticity. Prospective longitudinal studies are necessary to elucidate the long-term effects of illness progression on brain structure in major mood disorders.

Verapamil augmentation of lithium treatment improves outcome in mania unresponsive to lithium alone: preliminary findings and a discussion of therapeutic mechanisms.

OBJECTIVES: Attenuation of protein kinase C (PKC) is a mechanism common to both established (lithium, valproate) and some novel (tamoxifen) antimanic agents. Verapamil, although primarily known as a calcium channel blocker, also has PKC inhibitory activity. Verapamil has shown antimanic activity in some but not all studies. Therefore, we investigated verapamil, used alone or as an adjunctive treatment, in manic patients who did not respond to an initial adequate trial of lithium. METHODS: Each study phase lasted three weeks. Subjects were treated openly with lithium in Phase 1 (n = 45). Those who failed to respond were randomly assigned to double-blind treatment in Phase 2 with either verapamil (n = 10) or continued-lithium (n = 8). Phase 2 nonresponders (n = 10) were assigned to combined verapamil/lithium in Phase 3. RESULTS: Response in Phase 2 did not differ significantly between verapamil and continued-lithium. During Phase 3, response to combined treatment was significantly better than overall response to monotherapy in Phase 2 (Fisher's Exact test, p = 0.043). Mania ratings improved during combined treatment in Phase 3 by 88.2% (linear mixed model analysis, F = 4.34, p = 0.013), compared with 10.5% improvement during Phase 2. CONCLUSIONS: In this preliminary investigation, verapamil monotherapy did not demonstrate antimanic efficacy. By contrast, the combination of verapamil plus lithium was highly efficacious. Our findings thus suggest that verapamil may have potential utility as an adjunct to lithium. This effect may be mediated by additive actions on PKC inhibition, which may be an important mechanism for antimanic agents in general.

Three-dimensional mapping of hippocampal anatomy in unmedicated and lithium-treated patients with bipolar disorder.

Declarative memory impairments are common in patients with bipolar illness, suggesting underlying hippocampal pathology. However, hippocampal volume deficits are rarely observed in bipolar disorder. Here we used surface-based anatomic mapping to examine hippocampal anatomy in bipolar patients treated with lithium relative to matched control subjects and unmedicated patients with bipolar disorder. High-resolution brain magnetic resonance images were acquired from 33 patients with bipolar disorder (21 treated with lithium and 12 unmedicated), and 62 demographically matched healthy control subjects. Three-dimensional parametric mesh models were created from manual tracings of the hippocampal formation. Total hippocampal volume was significantly larger in lithium-treated bipolar patients compared with healthy controls (by 10.3%; p=0.001) and unmedicated bipolar patients (by 13.9%; p=0.003). Statistical mapping results, confirmed by permutation testing, revealed localized deficits in the right hippocampus, in regions corresponding primarily to cornu ammonis 1 subfields, in unmedicated bipolar patients, as compared to both normal controls (p=0.01), and in lithium-treated bipolar patients (p=0.03). These findings demonstrate the sensitivity of these anatomic mapping methods for detecting subtle alterations in hippocampal structure in bipolar disorder. The observed reduction in subregions of the hippocampus in unmedicated bipolar patients suggests a possible neural correlate for memory deficits frequently reported in this illness. Moreover, increased hippocampal volume in lithium-treated bipolar patients may reflect postulated neurotrophic effects of this agent, a possibility warranting further study in longitudinal investigations.

Context processing performance in bipolar disorder patients.

OBJECTIVES: Context processing is the adaptive control of current behavior through the use of prior context information. It has been found to be impaired in schizophrenia. Some studies have indicated that, compared with patients with schizophrenia, those with bipolar disorder (BPD) display a similar but less severe neuropsychological pattern of impairment. However, this cognitive dimension has not yet been examined in BPD patients in the existing literature. METHODS: An expectancy version of the AX continuous performance test (AX-CPT) was administered to 15 bipolar outpatients and 26 healthy controls. Patients with schizophrenia, in which context processing deficits are known to occur, were used as a reference group. RESULTS: Bipolar patients showed a context processing deficit relative to healthy controls, although this was less severe and generalized than in schizophrenia patients. CONCLUSIONS: These findings suggest there are milder impairments in context processing in BPD compared with schizophrenia. However, the severity of possible context processing deficits in BPD may have been underestimated in our sample of mostly euthymic outpatients.

Greater cortical gray matter density in lithium-treated patients with bipolar disorder.

BACKGROUND: The neurobiological underpinnings of bipolar disorder are not well understood. Previous neuroimaging findings have been inconsistent; however, new methods for three-dimensional (3-D) computational image analysis may better characterize neuroanatomic changes than standard volumetric measures. METHODS: We used high-resolution magnetic resonance imaging and cortical pattern matching methods to map gray matter differences in 28 adults with bipolar disorder, 70% of whom were lithium-treated (mean age = 36.1 +/- 10.5; 13 female subject), and 28 healthy control subjects (mean age = 35.9 +/- 8.5; 11 female subjects). Detailed spatial analyses of gray matter density (GMD) were conducted by measuring local proportions of gray matter at thousands of homologous cortical locations. RESULTS: Gray matter density was significantly greater in bipolar patients relative to control subjects in diffuse cortical regions. Greatest differences were found in bilateral cingulate and paralimbic cortices, brain regions critical for attentional, motivational, and emotional modulation. Secondary region of interest (ROI) analyses indicated significantly greater GMD in the right anterior cingulate among lithium-treated bipolar patients (n = 20) relative to those not taking lithium (n = 8). CONCLUSIONS: These brain maps are consistent with previous voxel-based morphometry reports of greater GMD in portions of the anterior limbic network in bipolar patients and suggest neurotrophic effects of lithium as a possible etiology of these neuroanatomic differences.

Smaller cingulate volumes in unipolar depressed patients.

BACKGROUND: The anterior cingulate cortex is a key structure in brain networks involved in mood regulation. Abnormalities in this brain region are possibly implicated in the pathophysiology of depression. This anatomical magnetic resonance imaging (MRI) study compared cingulate cortex volumes in unipolar depressed patients and age- and gender-matched healthy control subjects. METHODS: Thirty-one unmedicated DSM-IV unipolar patients (24 female, aged 39.2 +/- 11.9 years [mean +/- SD]) and 31 healthy control subjects (24 female, aged 36.7 +/- 10.7 years) were studied in a 1.5-T GE Signa magnet (General Electric Medical Systems, Milwaukee, Wisconsin). Cingulate volumes were compared by analysis of covariance with intracranial volume as the covariate. RESULTS: The unipolar patients had significantly smaller anterior and posterior cingulate volumes bilaterally compared with healthy control subjects. When patients were divided into currently depressed (n = 21) and remitted (n = 10) subgroups, currently depressed patients had significantly smaller anterior and posterior cingulate volumes bilaterally compared with healthy control subjects, whereas remitted patients had significantly smaller left anterior cingulate volumes compared with healthy individuals. CONCLUSIONS: Gray matter abnormalities in the cingulate cortex are implicated in the pathophysiology of unipolar depression. Smaller cingulate volumes in currently depressed patients support the hypothesis that cingulate cortex abnormalities are state dependent, whereas changes in left anterior cingulate might be trait related.

Two-year outcomes for interpersonal and social rhythm therapy in individuals with bipolar I disorder.

CONTEXT: Numerous studies have pointed to the failure of prophylaxis with pharmacotherapy alone in the treatment of bipolar I disorder. Recent investigations have demonstrated benefits from the addition of psychoeducation or psychotherapy to pharmacotherapy in this population. OBJECTIVE: To compare 2 psychosocial interventions: interpersonal and social rhythm therapy (IPSRT) and an intensive clinical management (ICM) approach in the treatment of bipolar I disorder. DESIGN: Randomized controlled trial involving 4 treatment strategies: acute and maintenance IPSRT (IPSRT/IPSRT), acute and maintenance ICM (ICM/ICM), acute IPSRT followed by maintenance ICM (IPSRT/ICM), or acute ICM followed by maintenance IPSRT (ICM/IPSRT). The preventive maintenance phase lasted 2 years. SETTING: Research clinic in a university medical center. PARTICIPANTS: One hundred seventy-five acutely ill individuals with bipolar I disorder recruited from inpatient and outpatient settings, clinical referral, public presentations about bipolar disorder, and other public information activities. INTERVENTIONS: Interpersonal and social rhythm therapy, an adaptation of Klerman and Weissman's interpersonal psychotherapy to which a social rhythm regulation component has been added, and ICM. MAIN OUTCOME MEASURES: Time to stabilization in the acute phase and time to recurrence in the maintenance phase. RESULTS: We observed no difference between the treatment strategies in time to stabilization. After controlling for covariates of survival time, we found that participants assigned to IPSRT in the acute treatment phase survived longer without a new affective episode (P = .01), irrespective of maintenance treatment assignment. Participants in the IPSRT group had higher regularity of social rhythms at the end of acute treatment (P<.001). Ability to increase regularity of social rhythms during acute treatment was associated with reduced likelihood of recurrence during the maintenance phase (P = .05). CONCLUSION: Interpersonal and social rhythm therapy appears to add to the clinical armamentarium for the management of bipolar I disorder, particularly with respect to prophylaxis of new episodes.

Anatomical MRI study of corpus callosum in unipolar depression.

Previous studies have suggested abnormal cerebral lateralization in major depressive disorder (MDD). Few controlled MRI studies have investigated the corpus callosum (CC), the largest commissura connecting the two cerebral hemispheres, in MDD. This study investigated anatomical abnormalities in the CC and its subdivisions in MDD patients. Twenty-two unmedicated MDD patients and 39 healthy subjects underwent brain magnetic resonance imaging (MRI). Measurements of the CC and its sub-regions were performed with a semi-automated software (NIH Image, version 1.62). ANCOVA with age, gender, and intra-cranial volume (ICV) as covariates showed no significant differences in CC measurements between patients and controls (df=1,56; p>0.05). However, patients with familial MDD had a significantly larger middle genu area (F(1,45)=4.252; p=0.045) compared to healthy controls, and significantly larger middle genu (F(1,13)=5.366; p=0.037), anterior splenium (F(1,13)=6.27; p=0.026), and middle splenium areas (F(1,13)=4.706; p=0.049) compared to patients with non-familial MDD. Although preliminary, our findings suggest that anatomical abnormalities in CC may be restricted to patients with familial MDD, with possible enlargement of CC in this particular sub-group. The possible role of callosal abnormalities in the pathogenesis of mood disorders should be further examined.

Structural brain changes in bipolar disorder using deformation field morphometry.

The objective of this study was to investigate anatomical brain abnormalities in adult bipolar patients using a deformation field morphometry technique. Our sample consisted of 32 right-handed bipolar I patients (men/women=16/16) and 32 right-handed, age and gender matched healthy controls. Deformation field morphometry analysis was performed on three-dimensional spoiled gradient recalled acquisition images. We found gender-specific structural differences between bipolar patients and healthy individuals. Bipolar men had significantly larger lateral ventricles (especially pronounced in the left hemisphere) and smaller left dorsolateral prefrontal cortex than healthy male controls. Our results are complementary to the findings of functional imaging and post-mortem studies that demonstrate abnormalities in the dorsolateral prefrontal cortex in bipolar patients.

1H magnetic resonance spectroscopy investigation of the dorsolateral prefrontal cortex in bipolar disorder patients.

BACKGROUND: Magnetic resonance spectroscopy studies (MRS) reported abnormally low levels of N-acetylaspartate (NAA, a marker of neuronal integrity) in dorsolateral prefrontal cortex (DLPFC) of adult bipolar patients, suggesting possible neuronal dysfunction. Furthermore, recent MRS reports suggested possible lithium-induced increase in NAA levels in bipolar patients. We examined with in vivo (1)H MRS NAA levels in the DLPFC of adult bipolar patients. METHODS: Ten DSM-IV bipolar disorder patients (6 lithium-treated, 4 drug-free) and 32 healthy controls underwent a short echo-time 1H MRS session, which localized an 8 cm3 single-voxel in the left DLPFC using a STEAM sequence. RESULTS: No significant differences between the two groups were found for NAA, choline-containing molecules (GPC+PC), or phosphocreatine plus creatine (PCr+Cr) (Student t-test, p > 0.05). Nonetheless, NAA/PCr+Cr ratios were significantly increased in lithium-treated bipolar subjects compared to unmedicated patients and healthy controls (Mann-Whitney U-test, p < 0.05). LIMITATIONS: Relatively small sample size may have reduced the statistical power of our analyses and the utilization of a single-voxel approach did not allow for the examination of other cortical brain areas. CONCLUSIONS: This study did not find abnormally reduced levels of NAA in left DLPFC of adult bipolar patients, in a sample of patients who were mostly on medications. However, elevated NAA/PCr+Cr ratios were shown in lithium-treated bipolar patients. Longitudinal 1H MRS studies should further examine NAA levels in prefrontal cortex regions in untreated bipolar patients before and after mood stabilizing treatment.

1H Magnetic resonance spectroscopy study of dorsolateral prefrontal cortex in unipolar mood disorder patients.

Neuroimaging and postmortem studies have suggested the involvement of the dorsolateral prefrontal cortex (DLPFC) in the pathophysioloy of unipolar disorder. We examined with in vivo 1H magnetic resonance spectroscopy (MRS) the levels of specific metabolites in the DLPFC of adult unipolar patients and the role of illness chronicity on DLPFC abnormalities. Nineteen unmedicated unipolar mood disorder patients and 19 age- and gender-matched healthy controls underwent a short echo-time 1H MRS examination localized to an 8-cm3 single voxel placed in the left DLPFC. There were no significant differences in metabolite levels, including N-acetylaspartate (NAA), phosphocreatine plus creatine (PCr+Cr) and choline-containing-compounds (GPC+PC), between the two groups. However, NAA/PCr+Cr ratios were significantly lower in the chronic than in the less chronically ill patients and healthy controls. The low levels of NAA/PCr+Cr ratios in the left DLPFC of unipolar patients who had been more chronically ill suggest a potential role for illness chronicity in neuronal abnormalities in the DLPFC in unipolar disorder. This could possibly be accounted for by neurodegenerative processes arising with the progression of the illness. Future 1H MRS investigations should longitudinally examine the role of illness chronicity on DLPFC abnormalities and their relationship with the symptoms of unipolar disorder.