Psychotropic and neurological medication effects on mitochondrial complex I and IV in rodent models

Mitochondrial complex I (NADH-dehydrogenase) and complex IV (cytochrome-c-oxidase) are reported to be affected by drugs used to treat psychiatric or neurodegenerative diseases, including antidepressants, antipsychotics, anxiolytics, mood stabilizers, stimulants, antidementia, and antiparkinsonian drugs. We conducted meta-analyses examining the effects of each drug category on complex I and IV. The electronic databases Pubmed, EMBASE, CENTRAL, and Google Scholar were searched for studies published between 1970 and 2018. Of 3105 screened studies, 68 articles covering 53 drugs were included in the meta-analyses. All studies assessed complex I and IV in rodent brain at the level of enzyme activity. Results revealed that selected antidepressants increase or decrease complex I and IV, antipsychotics and stimulants decrease complex I but increase complex IV, whereas anxiolytics, mood stabilizers, antidementia, and antiparkinsonian drugs preserve or even enhance both complex I and IV. Potential contributions to the drug effects were found to be related to the drugs' neurotransmitter receptor profiles with adrenergic (α1B), dopaminergic (D1/2), glutaminergic (NMDA1,3), histaminergic (H1), muscarinic (M1,3), opioid (OP1-3), serotonergic (5-HT_2A, 5-HT_2C, 5-HT_3A) and sigma (σ1) receptors having the greatest effects. The findings are discussed in relation to pharmacological mechanisms of action that might have relevance for clinical and research applications.

Brain cytochrome-c-oxidase as a marker of mitochondrial function: A pilot study in major depression using NIRS

BACKGROUND

Brain mitochondrial dysfunction is implicated in the pathophysiology of mood disorders. Brain cytochrome-c-oxidase (COX) activity is associated with the mitochondrial function. Near-infrared spectroscopy (NIRS) noninvasively measures oxidized COX (oxCOX) and tissue oxygenation index (TOI) reflecting cerebral blood flow and oxygenation.

METHODS

oxCOX and TOI were assessed in prefrontal cortex (Fp1/2, Brodmann area 10) in patients in a major depressive episode (N = 13) with major depressive disorder (MDD; N = 7) and bipolar disorder (BD; N = 6) compared with the controls (N = 10). One patient with MDD and all the patients with BD were taking medications. Computational modeling estimated oxCOX and TOI related indices of mitochondrial function and cerebral blood flow, respectively.

RESULTS

oxCOX was lower in patients than controls (p = .014) correlating inversely with depression severity (r = -.72; p = .006), driven primarily by lower oxCOX in BD compared with the controls. Computationally modeled mitochondrial parameters of the electron transport chain, such as the nicotinamide adenine dinucleotide ratio (NAD⁺ /NADH; p = .001) and the proton leak rate across the inner mitochondrial membrane (k_lk2 ; p = .008), were also lower in patients and correlated inversely with depression severity. No such effects were found for TOI.

CONCLUSIONS

In this pilot study, oxCOX and related mitochondrial parameters assessed by NIRS indicate an abnormal cerebral metabolic state in mood disorders proportional to depression severity, potentially providing a biomarker of antidepressant effect. Because the effect was driven by the medicated BD group, findings need to be evaluated in a larger, medication-free population.

Antidepressant medication exposure and 5-HT1A autoreceptor binding in major depressive disorder

OBJECTIVE

We have previously reported higher brain serotonin 1A (5-HT_1A ) autoreceptor binding in antidepressant-naïve patients with Major Depressive Disorder (MDD) compared with healthy volunteers, and a decrease in binding in MDD after selective serotonin reuptake inhibitor (SSRI) treatment. This SSRI effect is also present in rodents administered SSRIs chronically. We therefore sought to determine the duration of antidepressant medication effects on 5-HT_1A receptor binding after medication discontinuation.

METHODS

Positron emission tomography (PET) imaging with the 5-HT_1A receptor radioligand [¹¹ C]WAY-100635 was performed in 66 individuals with current DSM-IV MDD to examine relationships between 5-HT_1A binding and time since most recent antidepressant treatment. All subjects were medication-free for at least 2 weeks prior to scanning. Thirty-two additional MDD comparison subjects were antidepressant naïve.

RESULTS

No differences in [¹¹ C]WAY-100635 binding were observed between antidepressant naïve and antidepressant exposed MDD groups in 13 a priori cortical and subcortical regions of interest, including raphe autoreceptors, assessed simultaneously in linear mixed effects models. Furthermore, [¹¹ C]WAY-100635 binding did not correlate with time off antidepressants in the antidepressant exposed patients considering these ROIs. The same results were observed when effects of treatment discontinuation of any psychotropic medication used to treat their depression was examined.

CONCLUSION

These results indicate that any antidepressant-associated downregulation of 5-HT_1A autoreceptor binding reverses within 2 weeks of medication discontinuation. Since this effect is hypothesized to mediate the antidepressant action of SSRIs, and perhaps other antidepressants, it suggests that patients who need ongoing treatment may relapse rapidly when medication is discontinued. Moreover, 2 weeks appears to be a sufficiently long washout of antidepressant medications for a reliable measure of illness-related binding levels.

White matter tract integrity is associated with antidepressant response to lurasidone in bipolar depression

OBJECTIVES

Patients with bipolar disorder spend the most time in the depressed phase, and that phase is associated with the most morbidity and mortality. Treatment of bipolar depression lacks a test to determine who will respond to treatment. White matter disruptions have been found in bipolar disorder. Previous reports suggest that white matter disruptions may be associated with resistance to antidepressant medication, but this has never been investigated in a prospective study using a Food and Drug Administration (FDA)-approved medication.

METHODS

Eighteen subjects with bipolar disorder who were in a major depressive episode and off all medications were recruited. Magnetic resonance imaging was acquired using a 64-direction diffusion tensor imaging sequence on a 3T scanner. Subjects were treated with 8 weeks of open-label lurasidone. The Montgomrey-Asberg Depression Rating Scale (MADRS) was completed weekly. Tract-Based Spatial Statistics were utilized to perform a regression analysis of fractional anisotropy (FA) data with treatment outcome as assessed by percent change in MADRS as a regressor while controlling for age and sex, using a threshold of P (threshold-free cluster enhancement-corrected) <.05.

RESULTS

FA was positively correlated with antidepressant treatment response in multiple regions of the mean FA skeleton bilaterally, including tracts in the frontal and parietal lobes.

CONCLUSIONS

Greater disruptions in the white matter tracts in bipolar disorder were associated with poorer antidepressant response to lurasidone. The disruptions may potentially indicate treatment with a different antidepressant medication class. These results are limited by the open-label study design, sample size and lack of a healthy control group.

Risperidone-induced topological alterations of anatomical brain network in first-episode drug-naive schizophrenia patients: a longitudinal diffusion tensor imaging study

BACKGROUND

It remains unclear whether the topological deficits of the white matter network documented in cross-sectional studies of chronic schizophrenia patients are due to chronic illness or to other factors such as antipsychotic treatment effects. To answer this question, we evaluated the white matter network in medication-naive first-episode schizophrenia patients (FESP) before and after a course of treatment.

METHOD

We performed a longitudinal diffusion tensor imaging study in 42 drug-naive FESP at baseline and then after 8 weeks of risperidone monotherapy, and compared them with 38 healthy volunteers. Graph theory was utilized to calculate the topological characteristics of brain anatomical network. Patients' clinical state was evaluated using the Positive and Negative Syndrome Scale (PANSS) before and after treatment.

RESULTS

Pretreatment, patients had relatively intact overall topological organizations, and deficient nodal topological properties primarily in prefrontal gyrus and limbic system components such as the bilateral anterior and posterior cingulate. Treatment with risperidone normalized topological parameters in the limbic system, and the enhancement positively correlated with the reduction in PANSS-positive symptoms. Prefrontal topological impairments persisted following treatment and negative symptoms did not improve.

CONCLUSIONS

During the early phase of antipsychotic medication treatment there are region-specific alterations in white matter topological measures. Limbic white matter topological dysfunction improves with positive symptom reduction. Prefrontal deficits and negative symptoms are unresponsive to medication intervention, and prefrontal deficits are potential trait biomarkers and targets for negative symptom treatment development.

Characterization of brain mGluR5 binding in a pilot study of late-life major depressive disorder using positron emission tomography and [¹¹C]ABP688

The metabotropic glutamate receptor subtype 5 (mGluR5) has been implicated in the pathophysiology of mood and anxiety disorders and is a potential treatment target in major depressive disorder (MDD). This study compared brain mGluR5 binding in elderly patients suffering from MDD with that in elderly healthy volunteers using positron emission tomography (PET) and [(11)C]ABP688. Twenty elderly (mean age: 63.0 ± 6.3) subjects with MDD and twenty-two healthy volunteers in the same age range (mean age: 66.4 ± 7.3) were examined with PET after a single bolus injection of [(11)C]ABP688, with many receiving arterial sampling. PET images were analyzed on a region of interest and a voxel level to compare mGluR5 binding in the brain between the two groups. Differences in [(11)C]ABP688 binding between patients with early- and late-onset depression were also assessed. In contrast to a previously published report in a younger cohort, no significant difference in [(11)C]ABP688 binding was observed between elderly subjects with MDD and healthy volunteers. [(11)C]ABP688 binding was also similar between subgroups with early- or late-onset depression. We believe this is the first study to examine mGluR5 expression in depression in the elderly. Although future work is required, results suggest potential differences in the pathophysiology of elderly depression versus depression earlier in life.

Bipolar I and II versus unipolar depression: clinical differences and impulsivity/aggression traits

OBJECTIVE

To investigate distinguishing features between bipolar I, II and unipolar depression, and impulsivity/aggression traits in particular.

METHODS

Six hundred and eighty-five (n=685) patients in a major depressive episode with lifetime Unipolar (UP) depression (n=455), Bipolar I (BP-I) disorder (n=151), and Bipolar II (BP-II) (n=79) disorder were compared in terms of their socio-demographic and clinical characteristics.

RESULTS

Compared to unipolar patients, BP-I and BP-II depressed patients were significantly younger at onset of their first depressive episode, and were more likely to experience their first depressive episode before/at age of 15. They also had more previous affective episodes, more first- and second-degree relatives with history of mania, more current psychotic and subsyndromal manic symptoms, and received psychopharmacological and psychotherapy treatment at an earlier age. Furthermore, BP-I and BP-II depressed patients had higher lifetime impulsivity, aggression, and hostility scores. With regard to bipolar subtypes, BP-I patients had more trait-impulsivity and lifetime aggression than BP-II patients whereas the latter had more hostility than BP-I patients. As for co-morbid disorders, Cluster A and B Personality Disorders, alcohol and substance abuse/dependence and anxiety disorders were more prevalent in BP-I and BP-II than in unipolar patients. Whereas the three groups did not differ on other socio-demographic variables, BP-I patients were significantly more often unemployed that UP patients.

CONCLUSION

Our findings comport with major previous findings on differences between bipolar and unipolar depression. As for trait characteristics, bipolar I and II depressed patients had more life-time impulsivity and aggression/hostility than unipolar patients. In addition, bipolar I and II patients also differed on these trait characteristics.

Neuropsychological deficits in past suicide attempters with varying levels of depression severity

BACKGROUND

Our previous work identified deficits in interference processing and learning/memory in past suicide attempters who were currently depressed and medication-free. In this study, we extend this work to an independent sample studied at various stages of illness and treatment (mild symptoms, on average) to determine if these deficits in past suicide attempters are evident during a less severe clinical state.

METHOD

A total of 80 individuals with a past history of major depression and suicide attempt were compared with 81 individuals with a history of major depression and no lifetime suicide attempts on a battery of neurocognitive measures assessing attention, memory, abstract/contingent learning, working memory, language fluency and impulse control.

RESULTS

Past attempters performed more poorly in attention, memory and working memory domains, but also in an estimate of pre-morbid intelligence. After correction for this estimate, tests that had previously distinguished past attempters - a computerized Stroop task and the Buschke Selective Reminding Test - remained significantly worse in attempters. In a secondary analysis, similar differences were found among those with the lowest levels of depression (Hamilton Depression Rating Scale score <10), suggesting that these deficits may be trait markers independent of current symptomatology.

CONCLUSIONS

Deficits in interference processing and learning/memory constitute an enduring defect in information processing that may contribute to poor adaptation, other higher-order cognitive impairments and risk for suicidal behavior.

Life events: a complex role in the timing of suicidal behavior among depressed patients

Suicidal behavior is often conceptualized as a response to overwhelming stress. Our model posits that given a propensity for acting on suicidal urges, stressors such as life events or major depressive episodes (MDEs) determine the timing of suicidal acts. Depressed patients (n=415) were assessed prospectively for suicide attempts and suicide, life events and MDE over 2 years. Longitudinal data were divided into 1-month intervals characterized by MDE (yes/no), suicidal behavior (yes/no) and life event scores. Marginal logistic regression models were fit, with suicidal behavior as the response variable and MDE and life event score in either the same or previous month, respectively, as time-varying covariates. Among 7843 person-months, 33% had MDE and 73% had life events. MDE increased the risk for suicidal behavior (odds ratio (OR)=4.83, P⩽0.0001). Life event scores were unrelated to the timing of suicidal behavior (OR=1.06 per 100 point increase, P=0.32), even during a MDE (OR=1.12, P=0.15). However, among those without borderline personality disorder (BPD), both health- and work-related life events were key precipitants, as was recurrent MDE, with a 13-fold effect. The relationship of life events to suicidal behavior among those with BPD was more complex. Recurrent MDE was a robust precipitant for suicidal behavior, regardless of BPD comorbidity. The specific nature of life events is key to understanding the timing of suicidal behavior. Given unanticipated results regarding the role of BPD and study limitations, these findings require replication. Of note, that MDE, a treatable risk factor, strongly predicts suicidal behaviors is cause for hope.

Differentiating Army suicide attempters from psychologically treated and untreated soldiers: a demographic, psychological and stress-reaction characterization

BACKGROUND

Suicide is the leading cause of death in most armies during peace-time. The recent dramatic rise in suicides in the US Army further focuses attention on the causes of suicidal behavior in the military.

METHODS

This study investigated demographic characteristics, psychological profile and stress-related risk factors associated with suicide attempts in Israelis aged 18-21 years, who served in the Army in 2009. Soldiers who attempted suicide (N=60) were compared to soldiers treated by a mental health professional, but reported no suicidal behavior (N=58), and to controls (N=50).

RESULTS

Suicide attempters had lower socioeconomic status and less cognitive ability compared with treated soldiers and untreated control soldiers. Only 25% of the suicide attempters had received mental healthcare prior to the attempt. The majority of the attempts were non-lethal (86.2%), and only 5.2% used firearms. Attempters had more previous suicide attempts (37.9%) and deliberate selfharm incidents (19.3%), compared to almost no such behaviors in the other two groups. Following the suicide attempt, 77% were diagnosed with moderate to severe mental disorders, 44.8% personality disorders and 8.6% mood disorders. Attempters reported higher levels of general stress compared to their peers in the other two groups. Being away from home and obeying authority were especially more stressful in attempters.

CONCLUSIONS

Young soldiers are less prone to seek mental health assistance, despite suffering from higher levels of stress. Screening is required to detect soldiers at risk for suicidal behavior and preventive intervention will require active outreach.

Neuropsychological function and suicidal behavior: attention control, memory and executive dysfunction in suicide attempt

BACKGROUND

Executive dysfunction, distinct from other cognitive deficits in depression, has been associated with suicidal behavior. However, this dysfunction is not found consistently across samples.

METHOD

Medication-free subjects with DSM-IV major depressive episode (major depressive disorder and bipolar type I disorder) and a past history of suicidal behavior (n = 72) were compared to medication-free depressed subjects with no history of suicidal behavior (n = 80) and healthy volunteers (n = 56) on a battery of tests assessing neuropsychological functions typically affected by depression (motor and psychomotor speed, attention, memory) and executive functions reportedly impaired in suicide attempters (abstract/contingent learning, working memory, language fluency, impulse control).

RESULTS

All of the depressed subjects performed worse than healthy volunteers on motor, psychomotor and language fluency tasks. Past suicide attempters, in turn, performed worse than depressed non-attempters on attention and memory/working memory tasks [a computerized Stroop task, the Buschke Selective Reminding Task (SRT), the Benton Visual Retention Test (VRT) and an N-back task] but not on other executive function measures, including a task associated with ventral prefrontal function (Object Alternation). Deficits were not accounted for by current suicidal ideation or the lethality of past attempts. A small subsample of those using a violent method in their most lethal attempt showed a pattern of poor executive performance.

CONCLUSIONS

Deficits in specific components of attention control, memory and working memory were associated with suicidal behavior in a sample where non-violent attempt predominated. Broader executive dysfunction in depression may be associated with specific forms of suicidal behavior, rather than suicidal behavior per se.

Pollen counts and suicide rates. Association not replicated

OBJECTIVE

  To replicate a previously reported association between pollen counts and county suicide rates in the continental United States, across space and time.

METHOD

  The authors evaluated the relationship between airborne pollen counts and suicide rates in 42 counties of the continental United States, containing a pollen-counting station participating in the Aeroallergen Monitoring Network in the United States (N = 120,076 suicides), considering years' quarter, age group, sex, race, rural/urban location, number of local psychiatrists, and median household income, from 1999 to 2002. The county-level effects were broken into between-county and within-county.

RESULTS

  No within-county effects were found. Between-county effects for grass and ragweed pollen on suicide rates lost statistical significance after adjustment for median income, number of psychiatrists, and urban vs. rural location.

CONCLUSION

  Future research is necessary to reappraise the previously reported relationship between pollen levels and suicide rates that may have been driven by socioeconomic confounders.

Biodistribution, toxicology, and radiation dosimetry of 5-HT1A-receptor agonist positron emission tomography ligand [11C]CUMI-101

Sprague Dawley rats (10/sex/group) were given a single intravenous (iv) dose of CUMI-101 to determine acute toxicity of CUMI-101 and radiation dosimetry estimations were conducted in baboons with [(11)C]CUMI-101. Intravenous administration of CUMI-101 did not produce overt biologically or toxicologically significant adverse effects except transient hypoactivity immediately after dose in the mid- and high-dose groups, which is not considered to be a dose-limiting toxic effect. No adverse effects were observed in the low-dose group. The no observed adverse effect level (NOAEL) is considered to be 44.05 µg/kg for a single iv dose administration in rats. The maximum tolerated dose (MTD) was estimated to be 881 µg/kg for a single iv dose administration. The Medical Internal Radiation Dose (MIRDOSE) estimates indicate the maximum permissible single-study dosage of [(11)C]CUMI-101 in humans is 52 mCi with testes and urinary bladder as the critical organ for males and females, respectively.

The effect of social adjustment and attachment style on suicidal behaviour

OBJECTIVE

Prior studies examining the relationship between social adjustment and suicidal ideation or behaviour have not examined attachment. This study examines the effect of attachment on the association between current social adjustment and suicide attempt risk.

METHOD

Attachment, social adjustment, and history of suicide attempt were assessed in patients participating in research on major depressive disorder (N = 524). Suicide attempters and non-attempters were compared with attachment style and social adjustment using hierarchical logistic regression models. The two factor scoring method of the Adult Attachment Scale (secure vs. avoidant) was utilized as each measures unique aspects of attachment.

RESULTS

Anxious attachment (OR = 1.33; 95% CI = 1.016-1.728; P = 0.038) but not overall social adjustment (P = 0.14) was associated with a history of a past suicide attempt when both attachment and social adjustment were assessed in the same model. Among subtypes of social adjustment, work adjustment was associated with past history of suicide attempt (OR = 1.25; 95%CI = 1.019-1.540; P = 0.033). As impairment in work adjustment increased by 1 unit, the likelihood of reporting a suicide attempt increased by approximately 25%. There was no interaction between anxious attachment and work adjustment (P = 0.81).

CONCLUSION

Anxious attachment and work adjustment warrant further study as potential treatment targets in depressed suicidal patients.

Stress, genetics and epigenetic effects on the neurobiology of suicidal behavior and depression

Alterations in a number of neurobiological systems have been associated with suicidal behavior including the serotonergic and noradrenergic systems and the hypothalamic-pituitary-adrenal axis. Altered functioning of these systems may stem from both genetic and developmental causes. Adversity in early-life has developmental consequences on these systems that persist into adulthood. Genetic differences may also contribute to alterations in functioning of neurobiological systems. Moreover, the interaction of early-life experiences of adversity and genetic vulnerability is increasingly thought to play a role, including via epigenetic mechanisms.

Epigenetic regulation of serotonin transporter expression and behavior in infant rhesus macaques

Epigenetic mechanisms may moderate genetic and environmental risk (GxE) for mood disorders. We used an experimental rhesus macaque model of early life stress to test whether epigenetic regulation of serotonin transporter (5-HTT) may contribute to GxE interactions that influence behavior and emotion. We hypothesized that peripheral blood mononuclear cell (PBMC) DNA methylation within an 800 bp cytosine-phosphate-guanosine (CpG) island that overlaps with the 5-HTT transcription initiation start site, a hypothesized model of the same genomic region in brain tissue, would mediate or moderate the effects of early life stress and a functional 5-HTT promoter polymorphism (rh5-HTTLPR) on two outcomes: PBMC 5-HTT expression and behavioral stress reactivity. Eighty-seven infant rhesus macaques (3-4 months of age) were either mother reared in large social groups (n = 70) or nursery reared (n = 17). During a maternal/social separation, infants' blood was sampled and behavioral stress reactivity recorded. PBMC DNA and RNA samples were used to determine rh5-HTTLPR genotype, 5-HTT mRNA expression using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and 5-HTT CpG methylation status using sodium bisulfite pyrosequencing. Consistent with human data, carriers of the low-expressing rh5-HTTLPR alleles exhibited higher mean 5-HTT CpG methylation, which was associated with lower PBMC 5-HTT expression. Higher 5-HTT CpG methylation, but not rh5-HTTLPR genotype, exacerbated the effects of early life stress on behavioral stress reactivity in infants. 5-HTT CpG methylation may be an important regulator of 5-HTT expression early in development and may contribute to the risk for mood disorders observed in 'high-risk'5-HTTLPR carriers.

Evaluation of volume-based and surface-based brain image registration methods

Establishing correspondences across brains for the purposes of comparison and group analysis is almost universally done by registering images to one another either directly or via a template. However, there are many registration algorithms to choose from. A recent evaluation of fully automated nonlinear deformation methods applied to brain image registration was restricted to volume-based methods. The present study is the first that directly compares some of the most accurate of these volume registration methods with surface registration methods, as well as the first study to compare registrations of whole-head and brain-only (de-skulled) images. We used permutation tests to compare the overlap or Hausdorff distance performance for more than 16,000 registrations between 80 manually labeled brain images. We compared every combination of volume-based and surface-based labels, registration, and evaluation. Our primary findings are the following: 1. de-skulling aids volume registration methods; 2. custom-made optimal average templates improve registration over direct pairwise registration; and 3. resampling volume labels on surfaces or converting surface labels to volumes introduces distortions that preclude a fair comparison between the highest ranking volume and surface registration methods using present resampling methods. From the results of this study, we recommend constructing a custom template from a limited sample drawn from the same or a similar representative population, using the same algorithm used for registering brains to the template.

Elevated expression of tryptophan hydroxylase-2 mRNA at the neuronal level in the dorsal and median raphe nuclei of depressed suicides

Deficient levels of serotonin are associated with suicide and depression. Paradoxically, in the dorsal raphe nucleus (DRN) there are more serotonin neurons and more neuronal tryptophan hydroxylase-2 (TPH2) expression postmortem in depressed suicides. In this study, we sought to determine whether greater TPH2 expression in depressed suicides was the result of more TPH2 expression per neuron. In situ hybridization and computer-assisted image analysis were performed on tissue sections throughout the extent of the raphe nuclei at the level of silver grains per neuron to systematically quantify TPH2 neuronal expression. Depressed suicides have 26.5% more TPH2 grain density per neuron in the DRN compared with matched controls (P=0.04). The difference in grain density is greater at mid- and caudal anatomical levels across the rostrocaudal axis of the DRN. Densitometric analysis of TPH2 expression in the DRN subnuclei showed that higher expression levels were observed at posterior anatomical levels of depressed suicides (121% of control in the caudal subnucleus). Higher TPH2 expression in depressed suicides may explain more TPH2 protein and reflect a homeostatic response to deficient serotonin levels in the brains of depressed suicides. Localized changes in TPH2 expression in specific subnuclei of the DRN suggest that the serotonergic compensatory mechanism in depression and suicide is specifically regulated within the DRN and has implications for regions innervated by this subnucleus.

Evaluation of clinical prognostic models for suicide attempts after a major depressive episode

OBJECTIVE

In this study, we compare the performance of prognostic models of increasing complexity for prediction of future suicide attempt.

METHOD

Using data from a 2-year prospective study of 304 depressed subjects, a series of Cox proportional hazard regression models were developed to predict future suicide attempt. The models were evaluated in terms of discrimination (the ability to rank subjects in order of risk), calibration (accuracy of predicted probabilities of attempt), and sensitivity and specificity of risk group stratification based on cross-validated predicted probabilities.

RESULTS

Although an additive model with past attempt, smoking status, and suicidal ideation achieved 75% (cross-validated) sensitivity and specificity, models that performed best in terms of discrimination included interactions between predictor variables.

CONCLUSION

As several models had similar predictive power, clinical considerations and ease of interpretation may have a significant role in the final stage of model selection for assessing future suicide attempt risk.

Prospective studies of suicidal behavior in major depressive and bipolar disorders: what is the evidence for predictive risk factors?

OBJECTIVE

Prospective studies over the past 30 years have identified an array of predictive indicators for suicidal acts in mood disorders. However, prediction of suicidal behavior remains an elusive goal. This paper reviewed evidence from prospective studies for clinical factors that elevate risk of suicidal acts in that group.

METHOD

English language prospective studies of suicidal behavior in major depressive and bipolar disorders were examined.

RESULTS

The predictors with the best support were a past history of suicidal behavior and the presence of refractory or recurrent depressions. For other risk factors, there was either not enough data to consider them robust or findings were contradictory.

CONCLUSION

Future studies must not only be comprehensive in their inclusion of potentially contributing factors, but must also address their relative importance towards the goal of developing predictive models and enhance suicide prevention efforts.

Risk factors for suicide completion in major depression: a case-control study of impulsive and aggressive behaviors in men

OBJECTIVE

Major depression is a major risk factor for suicide. However, not all individuals with major depression commit suicide. Impulsive and aggressive behaviors have been proposed as risk factors for suicide, but it remains unclear whether their effect on the risk of suicide is at least partly explained by axis I disorders commonly associated with suicide, such as major depression. With a case-control design, a comparison of the level of impulsive and aggressive behaviors and the prevalence of associated psychopathology was carried out with control for the presence of primary psychopathology.

METHOD

One hundred and four male suicide completers who died during an episode of major depression and 74 living depressed male comparison subjects were investigated with proxy-based interviews by using structured diagnostic instruments and personality trait assessments.

RESULTS

The authors found that current (6-month prevalence) alcohol abuse/dependence, current drug abuse/dependence, and cluster B personality disorders increased the risk of suicide in individuals with major depression. Also, higher levels of impulsivity and aggression were associated with suicide. An analysis by age showed that these risk factors were more specific to younger suicide victims (ages 18-40). A multivariate analysis indicated that current alcohol abuse/dependence and cluster B personality disorder were two independent predictors of suicide.

CONCLUSIONS

Impulsive-aggressive personality disorders and alcohol abuse/dependence were two independent predictors of suicide in major depression, and impulsive and aggressive behaviors seem to underlie these risk factors. A developmental hypothesis of suicidal behavior, with impulsive and aggressive behaviors as the starting point, is discussed.

Clinical features of depressed patients with or without a family history of alcoholism

OBJECTIVE

To compare clinical features of depressed subjects without alcoholism but with a family history of alcoholism to a depressed group without alcoholism and without a family history of alcoholism.

METHOD

Clinical and demographic data of 209 depressed subjects without a history of alcoholism in first-degree relatives and 73 depressed individuals with a history of alcoholism in first-degree relatives were compared. Subjects with a personal history of alcoholism were excluded.

RESULTS

Depressed subjects with a family history of alcoholism have a significantly higher prevalence of reported childhood physical and sexual abuse and post-traumatic stress disorder (PTSD), make more suicide attempts, and have greater intent to die at the time of their most lethal suicide attempt, compared to depressed subjects without a family history of alcoholism.

CONCLUSION

Depressed patients with a family history of alcoholism are at greater risk for suicidal behavior and PTSD and may require more careful management.

Zinc pyrithione induces apoptosis and increases expression of Bim

We demonstrate herein that zinc pyrithione can induce apoptosis at nanomolar concentrations. Zinc pyrithione was a potent inducer of cell death causing greater than 40-60% apoptosis among murine thymocytes, murine splenic lymphocytes and human Ramos B and human Jurkat T cells. Conversely, the addition of a zinc chelator protected thymocytes against zinc pyrithione induced apoptosis indicating these responses were specific for zinc. Zinc-induced apoptosis was dependent on transcription and translation which suggested possible regulation by a proapoptotic protein. Indeed, zinc induced a 1.9 and 3.4 fold increase respectively in expression of the BimEL and BimL isoforms and also stimulated production of the most potent isoform, BimS. This increase in Bim isoform expression was dependent on transcription being blocked by treatment with actinomycin D. Overexpression of Bcl-2 or Bcl-xL provided substantial protection of Ramos B and Jurkat T cells against zinc-induced apoptosis. Zinc also activated the caspase cascade demonstrated by cleavage of caspase 9. Addition of specific inhibitors for caspase 9 and caspase 3 also blocked zinc-induced apoptosis. The data herein adds to the growing evidence that free or unbound zinc could be harmful to cells of the immune system.

Rates of lifetime suicide attempt and rates of lifetime major depression in different ethnic groups in the United States

OBJECTIVE

Rates of major depression and suicide vary across ethnic groups within the US. This also may be true of suicide attempts.

METHOD

Data on lifetime suicidal behavior and major depression among Mexican American, Cuban American, and Puerto Rican adults who participated in the Hispanic Health and Nutrition Epidemiologic Survey were pooled with Epidemiological Catchment Area Study data for Blacks, Whites and Hispanics.

RESULTS

Rates of major depression ranged from 9.3 (Puerto Ricans) to 3.24% (Cuban Americans). Puerto Ricans and whites had the highest rates of depression. Similarly, suicide attempt rates ranged from 9.1% for Puerto Ricans to 1.9% for Cuban Americans. Puerto Ricans had higher suicide attempt rates compared with other groups.

CONCLUSION

This study underscores that there are differences between Hispanic ethnic groups. The impact of the migration process, socioeconomic status, and acculturation may underlie differences in major depression and suicide attempt rates across ethnic groups.

Postmortem mu-opioid receptor binding in suicide victims and controls

BACKGROUND

Endogenous opiates may reinforce self-injurious behavior in animal and human subjects. Higher postmortem mu-opioid receptor binding is reported in some brain regions in young compared with older suicide victims. The present study compared opioid receptor binding kinetics in postmortem brains of young suicide victims and matched controls in two brain areas.

METHODS

The density (Bmax) and affinity (K(D)) of the mu-opioid receptors were assayed postmortem using [3H] DAGO in prefrontal cortex (PFC) and pre-post central gyri (PPCG) in 9 suicide victims and 10 controls, matched for age and gender ratio.

RESULTS

Binding indices did not differ between suicide victims and controls in either brain area and did not correlate with age. PFC Bmax was higher than PPCG Bmax (F=8.030; df=1,16; p=.012) for the combined sample. There was no brain region difference in K(D) between PFC and PPCG, but the interaction between K(D) and group was significant (F = 5.890; df = 1,16; p = .027). The K(D) in the suicide victims was lower than controls in the PFC and higher than controls in the PPCG.

CONCLUSION

Our study demonstrated more mu-opioid receptors in PFC compared with PPCG binding regardless of suicide status. The region-dependent differences in binding affinity in suicide victims may reflect regionally different opiate transmission.

Upregulation of CB1 receptors and agonist-stimulated [35S]GTPgammaS binding in the prefrontal cortex of depressed suicide victims

Endogenous and exogenous cannabinoids (CBs) acting through the CB(1) receptors have been implicated in the regulation of several behavioral and neuroendocrine functions. Modulation of endocannabinoidergic system by ethanol in mouse brain, and the association of suicide and mood disorders with alcoholism suggest possible involvement of the cannabinoidergic system in the pathophysiology of depression and suicide. Therefore, the present study was undertaken to examine the levels of CB(1) receptors and mediated signaling in the dorsolateral prefrontal cortex (DLPFC) of subjects with major depression who had died by suicides (depressed suicides, DS). [(3)H]CP-55,940 and CB(1) receptor-stimulated [(35)S]GTPgammaS binding sites were analyzed in membranes obtained from DLPFC of DS (10) and matched normal controls (10). Upregulation (24%, P<0.0001) of CB(1) receptor density (B(max)) was observed in DS (644.6+/-48.8 fmol/mg protein) compared with matched controls (493.3+/-52.7 fmol/mg protein). However, there was no significant alteration in the affinity of receptor (DS; 1.14+/-0.08 vs control; 1.12+/-0.10 nM). Higher density of CB(1) receptors in DS (38%, P<0.001) was also demonstrated by Western blot analysis. The CB(1) receptor-stimulated [(35)S]GTPgammaS binding was significantly greater (45%, P<0.001) in the DLPFC of DS compared with matched controls. The observed upregulation of CB(1) receptors with concomitant increase in the CB(1) receptor-mediated [(35)S]GTPgammaS binding suggests a role for enhanced cannabinoidergic signaling in the prefrontal cortex of DS. The cannabinoidergic system may be a novel therapeutic target in the treatment of depression and/or suicidal behavior.

Abnormalities of myelination in schizophrenia detected in vivo with MRI, and post-mortem with analysis of oligodendrocyte proteins

Schizophrenia unfolds during the late period of brain maturation, while myelination is still continuing. In the present study, we used MRI and T2 relaxation analysis to measure the myelin water fraction in schizophrenia. In schizophrenia (n=30) compared with healthy subjects (n=27), overall white matter showed 12% lower myelin water fraction (P=0.031), with the most prominent effects on the left genu of the corpus callosum (36% lower, P=0.002). The left anterior genu was affected in both first-episode (P=0.035) and chronic patients (P=0.011). In healthy subjects, myelin water fraction in total white matter and in frontal white matter increased with age, and with years of education, indicating ongoing maturation. In patients with schizophrenia, neither relation was statistically significant. Post-mortem studies of anterior frontal cortex demonstrated less immunoreactivity of two oligodendrocyte-associated proteins in schizophrenia (2',3'-cyclic nucleotide 3'-phosphodiesterase by 33%, P=0.05; myelin-associated glycoprotein by 27%, P=0.14). Impaired myelination in schizophrenia could contribute to abnormalities of neural connectivity and persistent functional impairment in the illness.

Altered immunoreactivity of complexin protein in prefrontal cortex in severe mental illness

Recent imaging and postmortem studies suggest that impaired connectivity is involved in the pathophysiology of schizophrenia and major affective disorders. We investigated the presynaptic proteins complexin (Cx) I and Cx II in postmortem prefrontal cortex in schizophrenia (n = 13; six suicide, seven nonsuicide), major depression (n= 11, all suicide) and controls (n = 11) with an enzyme-linked immunoadsorbent assay (ELISA). Overall analysis indicated a significant difference between groups (F = 3.93, P = 0.007). Cx I (enriched in inhibitory terminals) was decreased 33% in schizophrenia (26% in schizophrenia/nonsuicide, 42% in schizophrenia/suicide) and 27% in major depression. Cx II (enriched in excitatory terminals) was not significantly different. Analysis of the ratio of Cx II/Cx I was carried out as an indication of the balance of excitatory to inhibitory terminals. A significant difference between groups (ANOVA, F = 6.42, P = 0.005) was observed. The mean value of Cx II/Cx I was significantly increased by 34% in schizophrenia (26% in schizophrenia/nonsuicide and 43% in schizophrenia/suicide) and by 32% in depression compared with control (Student-Newman-Keuls test, P = 0.05). Immunoreactivities of the two complexins were highly correlated in all groups. However, compared with controls and depression, samples from cases with schizophrenia appeared to have relatively less Cx I for similar amounts of Cx II. Immunocytochemical studies of rat frontal cortex after 3 weeks treatment with chlorpromazine, trifluoperazine or haloperidol revealed no differences in complexins, synaptophysin, SNAP-25, syntaxin or VAMP in comparison with animals treated with vehicle. Alterations of complexins may contribute to the molecular substrate for abnormalities of neural connectivity in severe mental disorders.

Understanding the neurobiology of suicidal behavior

Our current knowledge about the neurobiology of suicide is still limited. Technical limitations and the complexity of the CNS are major obstacles. However, there is evidence for a hereditary disposition to suicide, which appears to be independent of diagnosis. Clinical, postmortem, genetic, and animal studies suggest that serotonin has a central role. The main regions of interest in the CNS have been the dorsal and median raphe nuclei in the midbrain that host the main serotonergic cell bodies and the prefrontal cortex, particularly the ventral PFC, innervated by the serotonergic system. In vivo and postmortem studies indicate serotonergic hypofunction in suicide and serious suicide attempts. This deficiency in turn can lead to a predisposition to impulsive and aggressive behavior, probably due to a breakdown in the inhibitory function of the ventral prefrontal cortex as a result of less serotonin input. In the context of this predisposition and the development of mental illness or other life stressors, the individual is at risk of acting on suicidal thoughts. Such deficient serotonin input into the PFC may arise as a result of genetic, parenting, head injury, and other effects. Identifying psychiatric, social, and environmental predictors of suicide are studied to improve prediction and prevention of suicide. A better understanding of the neurobiology of suicide can help detect at risk populations and help develop better treatment interventions.

Identifying and managing suicide risk in bipolar patients

Bipolar patients have been shown to be at high risk for suicidal behavior. Therefore, identifying potentially suicidal patients is necessary in the treatment of bipolar patients. A stress-diathesis model for suicidal behavior has been proposed to assist clinicians in determining which patients are at risk. In the model, suicidal behavior is the result of the interaction between an individual's threshold for suicidal acts and the stressors that can lead to suicidal behavior. Suicide risk factors can then be categorized as either diathesis-related or stress-related. In a study applying the model of suicidal behavior to bipolar disorder, bipolar patients who attempted suicide had higher levels of suicidal ideation, lifetime aggression, and substance abuse than the comparison group of nonattempters. Attempters had twice the number of major depressive episodes. Once high-risk patients are identified, their suicide risk can be managed through treatments such as prophylactic lithium treatment and other pharmacologic approaches.

Serotonin 1A receptors, serotonin transporter binding and serotonin transporter mRNA expression in the brainstem of depressed suicide victims

Suicide and depression are associated with reduced serotonergic neurotransmission. In suicides, there is a reduction in serotonin transporter (SERT) sites and an increase in postsynaptic 5-HT(1A) receptors in localized regions of the prefrontal cortex. In depression, there is a diffuse decrease in SERT binding throughout the dorsoventral extent of the prefrontal cortex. Serotonergic innervation of the prefrontal cortex arises predominantly from neurons in the brainstem dorsal raphe nucleus (DRN). We, therefore, examined postmortem SERT binding and mRNA expression, as well as 5-HT(1A) autoreceptor binding in the DRN of 10 matched pairs of controls and depressed suicide victims. The concentration of SERT sites, SERT mRNA, and 5-HT(1A) binding was not different between controls and suicides (p >.05). In the DRN of suicides, the volume of tissue defined by 5-HT(1A) binding was 40% smaller than controls. An index of the total number of 5-HT(1A) receptors (receptor binding x volume of receptor distribution) was 43.3% lower in the DRN of suicides, compared with controls. The suicide group had 54% fewer DRN neurons expressing SERT mRNA compared with controls. In the serotonin neurons that expressed the SERT gene, expression per neuron was greater in suicides. Less total 5-HT(1A) and SERT binding is consistent with results of in vivo studies in depression. Less feedback inhibition of serotonin DRN firing via 5-HT(1A) autoreceptors and enhancement of serotonin action due to less uptake of serotonin, is consistent with compensatory changes in response to hypofunction in depressed suicides.

Aggressivity, suicide attempts, and depression: relationship to cerebrospinal fluid monoamine metabolite levels

BACKGROUND

We have proposed a stress-diathesis model for suicidal behavior, in which major depression is a stressor and the diathesis is shared with aggression. Neurotransmitter correlates of the stress or diathesis have not been adequately evaluated by previous studies, because they did not simultaneously examine the relationship of multiple neurotransmitters to all three psychopathologies in the same population. In the present study we investigated the relationship of monoamine metabolites to aggressivity, suicidal behavior, and depression in patients with mood disorders.

METHODS

Ninety-three drug-free subjects with a major depressive episode underwent lumbar puncture and psychiatric evaluation. Cerebrospinal fluid CSF levels of 5hydroxyindolacetic acid (5-HIAA), homovanillic acid (HVA) and methoxy-hydroxy-phenylglycol (MHPG) were assayed. The relationships between monoamine metabolites and clinical variables were statistically evaluated.

RESULTS

Higher lifetime aggressivity correlated significantly with lower CSF 5-HIAA. Lower CSF 5-HIAA and greater suicidal intent were found in high-lethality suicide attempters compared with low-lethality suicide attempters. Low-lethality attempters did not differ biologically from nonattempters. No correlation between CSF HVA and any of the psychopathological variables was found. Only aggression showed a trend statistically in correlating positively with CSF MHPG levels.

CONCLUSIONS

Lower CSF 5-HIAA concentration was independently associated with severity of lifetime aggressivity and a history of a higher lethality suicide attempt and may be part of the diathesis for these behaviors. The dopamine and norepinephrine systems do not appear to be as significantly involved in suicidal acts, aggression, or depression. The biological correlates of suicide intent warrant further study.

The relationship of childhood abuse to impulsivity and suicidal behavior in adults with major depression

OBJECTIVE

This study investigated whether a higher frequency of reported childhood trauma would be found in depressed adults with higher levels of trait impulsivity, aggression, and suicidal behavior.

METHOD

In 136 depressed adult inpatients, the authors assessed trait impulsivity, aggression history, and number of lifetime suicide attempts as well as the medical lethality and the intent to die associated with the most lethal attempt. These variables were then compared between those with and those without a reported history of childhood physical or sexual abuse.

RESULTS

Subjects who reported an abuse history were more likely to have made a suicide attempt and had significantly higher impulsivity and aggression scores than those who did not report an abuse history. Impulsivity and aggression scores were significantly higher in subjects with a history of at least one suicide attempt. A logistic regression analysis revealed that abuse history remained significantly associated with suicide attempt status after adjustment for impulsivity, aggression history, and presence of borderline personality disorder. Among those who attempted suicide, there were no significant differences in severity of suicidal behavior between those with and without a childhood history of abuse.

CONCLUSIONS

Abuse in childhood may constitute an environmental risk factor for the development of trait impulsivity and aggression as well as suicide attempts in depressed adults. Alternatively, impulsivity and aggression may be inherited traits underlying both childhood abuse and suicidal behavior in adulthood disorders. Additional research is needed to estimate the relative contributions of heredity and environmental experience to the development of impulsivity, aggression, and suicidal behavior.

Ethnic and sex differences in suicide rates relative to major depression in the United States

OBJECTIVE

Suicide rates differ between ethnic groups in the United States. Since suicide is commonly associated with a mood disorder, the authors compared suicide rates relative to depression rates in five ethnic groups in the United States.

METHOD

Rates of major depression were generated from the Epidemiologic Catchment Area study and the Hispanic Health and Nutrition Epidemiologic Survey. Sociodemographic effects were determined by examining depression rates for respondents who were separated or divorced, earning low incomes, or not working for pay. The survey data were analyzed with age and sex standardization to generate 1-year prevalence rates of major depression. The depression rates of the different ethnic groups were compared and were examined in relation to suicide rates.

RESULTS

The 1-year prevalence rates of major depression were 3.6% for whites, 3.5% for blacks, 2.8% for Mexican Americans, 2.5% for Cuban Americans, and 6.9% for Puerto Ricans. Compared to the rate for whites, the rate of depression was significantly higher in Puerto Ricans and significantly lower in Mexican Americans. Relative to the depression rates, the annual suicide rates were higher for males than for females. Mexican American and Puerto Rican males had lower relative suicide rates than white males.

CONCLUSIONS

Identifying reasons for differences in suicide rates relative to depression among ethnic groups and between males and females may suggest interventions to reduce suicide rates. Some possibilities are that depression differs in form or severity or that unidentified factors protect against suicide in different subgroups.

Dopamine D(2) receptor availability and amphetamine-induced dopamine release in unipolar depression

BACKGROUND

Reduced dopaminergic transmission has been implicated in the pathophysiology of major depression. The aim of the present study was to measure striatal D(2) receptor availability and amphetamine-induced dopamine release in nonpsychotic, unmedicated, unipolar patients during an episode of major depression.

METHODS

The striatal equilibrium specific to nonspecific partition coefficient (V(3)") of the D(2) receptor antagonist [(123)I]IBZM was measured with single photon emission computerized tomography before and after amphetamine administration in 9 depressed subjects and 10 matched healthy control subjects.

RESULTS

No significant differences were observed in preamphetamine D(2) receptor availability between depressed patients (0.73 +/- 0.08) and control subjects (0.78 +/- 0.10, p =.23). Amphetamine-induced reduction in [(123)I]IBZM V(3)" (DeltaV(3)") was similar in depressed patients (-9.8 +/- 5.5%) and control subjects (-7.8 +/- 2.5%, p =.32). Amphetamine induced a transient improvement in symptomatology in depressed patients, but this improvement did not correlate with [(123)I]IBZM DeltaV(3)".

CONCLUSIONS

This study did not replicate previously reported alterations in striatal D(2) receptor density in depressed patients and suggests that stimulant-induced dopamine release is not altered in major depression.

Prolactin response to dl-fenfluramine challenge before and after treatment with paroxetine

The prolactin response to dl-fenfluramine (an indirect central serotonin agonist) challenge has been used to assess serotonergic function and appears to be blunted in depressed patients. We used this method to determine whether the serotonergic deficit in depressed patients is corrected by treatment with paroxetine. Prior to treatment with paroxetine sixteen depressed patients received a placebo challenge followed by a dl-fenfluramine challenge the next day. The same two challenges were repeated after treatment. Prolactin baseline levels were measured before pill administration, and then hourly for 5 hours. Fenfluramine/norfenfluramine levels were assayed at each time point after drug administration. Treatment with paroxetine significantly increased the baseline prolactin level independently of treatment response but positively correlated with paroxetine dose. We found that pre-treatment prolactin response to dl-fenfluramine challenge did not predict clinical response to paroxetine, nor did the prolactin response change significantly after treatment. There was no significant difference in the post-treatment prolactin response between treatment responders and treatment non-responders. We found evidence of increased prolactin levels that may reflect effects of paroxetine in enhancing serotonin levels. Acute release of serotonin as measured by the prolactin response to fenfluramine is not altered by paroxetine treatment.

The neurobiology and genetics of suicide and attempted suicide: a focus on the serotonergic system

Numerous abnormalities have been found in the serotonergic system in suicide attempters and completers. There is considerable evidence that the serotonergic system is partly under genetic control and that as yet unknown genetic factors mediate the risk for suicidal behavior independently of the genetic factors responsible for the heritability of major psychiatric conditions associated with suicide. An argument is made that there is a relationship of genetic variants to intermediate phenotypes, such as impulsivity, psychomotor change, pathological aggression and biological abnormalities including specific gene products. A variety of biological indices have been generated by new approaches using postmortem tissue and in vivo imaging that will provide a rich substrate for further genetic studies.

Neuropsychological dysfunction in depressed suicide attempters

OBJECTIVE

Neuropsychological deficits in the context of psychiatric disease may be associated with suicide risk. In this study, neuropsychological performance was compared among depressed patients with at least one prior suicide attempt of high lethality, depressed patients with low-lethality prior attempts, depressed patients with no prior suicide attempts, and nonpatients.

METHOD

Fifty unmedicated patients in a major depressive episode (21 with no history of suicide attempts and 14 and 15 patients with previous attempts of low and high lethality, respectively) and 22 nonpatients were assessed. Groups were comparable in age, education, occupational level, and estimated premorbid intelligence. The neuropsychological battery produced scores within five composite domains: general intellectual functioning (current), motor functioning, attention, memory, and executive functioning.

RESULTS

Patients whose prior suicide attempts were of high lethality performed significantly worse than all groups on tests of executive functioning and were the only group to perform significantly worse than nonpatients on tests of general intellectual functioning, attention, and memory. A discriminant function analysis revealed two prominent dimensions in the data: one that discriminated high-lethality suicide attempters from all other groups (primarily associated with performance on tests of executive functioning) and another that discriminated all depressed patient groups from nonpatients (associated with performance on measures of attention and memory). For the patients with high-lethality prior suicide attempts, deficits did not appear to reflect diffuse brain damage from past attempts, since the results of tests commonly affected by diffuse injury were not selectively impaired.

CONCLUSIONS

Neuropsychological deficits in depressed patients with high-lethality prior suicide attempts suggest impairment of executive functioning beyond that typically found in major depression. This more extensive neuropsychological impairment in the context of depression may be a risk factor for severe suicide attempts.

Delusions and suicidality

OBJECTIVE

Delusions have been considered a risk factor for suicidal behavior. To determine whether specific delusion types are related to suicidal behaviors, the authors compared the clinical characteristics of patients with mood disorders and schizophrenia who did and did not have a history of suicide attempts.

METHOD

After admission for inpatient or outpatient psychiatric treatment, 429 patients (ages 14-72 years; 47.1% male; and 73.0% Caucasian) were assessed with a structured clinical interview that generated axis I and II diagnoses. In addition, their psychiatric symptoms, history of suicide attempts, and overall functioning were rated.

RESULTS

Data for three diagnostic subgroups (223 patients with major depression, 150 with schizophrenia, and 56 with bipolar disorder) were analyzed separately. Multivariate analyses did not find evidence of a relationship between delusions and history of suicidal ideation or suicide attempts in any of the diagnostic groups.

CONCLUSIONS

This study did not find evidence that the presence of delusions distinguished persons with or without a history of suicide attempt.

Recent life events, social adjustment, and suicide attempts in patients with major depression and borderline personality disorder

This study investigated the impact of recent life events and social adjustment on suicide attempter status in 34 patients with major depression, 24 patients with borderline personality disorder, and 22 patients with co-morbid major depression and borderline personality disorder. Suicide attempters reported more recent life events and scored lower on a measure of social adjustment in their families and overall social adjustment, compared with non-attempters. Borderline disordered and borderline or depressed patients were more likely to have attempted suicide than patients with major depression only. Recent life events did not predict attempter status. Lower social adjustment in the immediate family and lower overall social adjustment were predictive of suicide attempter classification, regardless of diagnosis. Borderline disordered patients low on overall social adjustment were over 16 times more likely to have attempted suicide than patients diagnosed with major depression only. Recent life events may elevate suicide risk in groups already at high risk for suicide completion, whereas high levels of social adjustment may be protective against stress-related suicidal behavior.

Treating the substance-abusing suicidal patient

Studies concerning the treatment of substance-abusing suicidal patients are scarce despite the frequent presence of suicidal behavior among this population. Indeed, suicidality (ideation or behavior) is generally an exclusion criterion for participation in treatment studies of subjects with alcohol or drug abuse. Consequently, to date, little is known about the optimal treatment of this population. The first study involving substance-abusing suicidal patients was an open-label trial conducted in the early 1990s. This study involved 12 patients, all of whom demonstrated recent suicidal ideations and had made a lifetime suicide attempt. The results of that open-label study demonstrated significant within-group improvement in both depressive symptoms (including suicidal ideations) and level of drinking. However, substantial residual depressive symptoms and drinking persisted at the end of the trial. Also, because no placebo control group was utilized, the authors of that study could not rule out the possibility that the apparent therapeutic effect from fluoxetine was the result of the placebo effect. To date, only one double-blind, placebo-controlled study of subjects with alcohol or substance abuse has included substantial numbers of suicidal patients. The study involved 51 subjects, of whom 20 (39%) had made a suicide attempt in the current depressive episode, 31 (61%) had made a suicide attempt in their lifetime, and 46 (90%) had reported suicidal ideations in the week before hospitalization. The results of that double-blind, placebo-controlled study suggest that fluoxetine was effective in decreasing but not eliminating both the depressive symptoms (including suicidal ideations) and the level of alcohol consumption among a study group of subjects with comorbid major depressive disorder and alcohol dependence, many of whom displayed suicidal ideations. A secondary data analysis from that study suggested that cigarette smoking is also significantly decreased by fluoxetine, but the magnitude of the decrease is limited and few of these patients totally quit smoking with fluoxetine treatment alone. Another secondary data analysis from that study suggested that marijuana smoking was also significantly decreased in a subgroup of subjects who demonstrated cannabis abuse and that the magnitude of this improvement was robust. A third secondary data analysis from that study suggested that cocaine abuse acts as a predictor of poor outcome for both depressive symptoms (including suicidality) and level of alcohol use in this population. The results of a 1-year naturalistic follow-up study involving the patients from that study suggest that the benefits of fluoxetine in decreasing depressive symptoms and level of drinking persist 1 year after entering the treatment program. To date, no other double-blind, placebo-controlled studies involving substantial numbers of substance-abusing suicidal patients have been reported to either confirm or refute these findings. Further studies are clearly warranted to evaluate the efficacy of various pharmacotherapeutic agents and various psychotherapies in the treatment of substance-abusing suicidal patients.

Continuation pharmacotherapy in the prevention of relapse following electroconvulsive therapy: a randomized controlled trial

CONTEXT

Electroconvulsive therapy (ECT) is highly effective for treatment of major depression, but naturalistic studies show a high rate of relapse after discontinuation of ECT.

OBJECTIVE

To determine the efficacy of continuation pharmacotherapy with nortriptyline hydrochloride or combination nortriptyline and lithium carbonate in preventing post-ECT relapse.

DESIGN

Randomized, double-blind, placebo-controlled trial conducted from 1993 to 1998, stratified by medication resistance or presence of psychotic depression in the index episode.

SETTING

Two university-based hospitals and 1 private psychiatric hospital.

PATIENTS

Of 290 patients with unipolar major depression recruited through clinical referral who completed an open ECT treatment phase, 159 patients met remitter criteria; 84 remitting patients were eligible and agreed to participate in the continuation study.

INTERVENTIONS

Patients were randomly assigned to receive continuation treatment for 24 weeks with placebo (n = 29), nortriptyline (target steady-state level, 75-125 ng/mL) (n = 27), or combination nortriptyline and lithium (target steady-state level, 0.5-0.9 mEq/L) (n = 28).

MAIN OUTCOME MEASURE

Relapse of major depressive episode, compared among the 3 continuation groups.

RESULTS

Nortriptyline-lithium combination therapy had a marked advantage in time to relapse, superior to both placebo and nortriptyline alone. Over the 24-week trial, the relapse rate for placebo was 84% (95% confidence interval [CI], 70%-99%); for nortriptyline, 60% (95% CI, 41%-79%); and for nortriptyline-lithium, 39% (95% CI, 19%-59%). All but 1 instance of relapse with nortriptyline-lithium occurred within 5 weeks of ECT termination, while relapse continued throughout treatment with placebo or nortriptyline alone. Medication-resistant patients, female patients, and those with more severe depressive symptoms following ECT had more rapid relapse.

CONCLUSIONS

Our study indicates that without active treatment, virtually all remitted patients relapse within 6 months of stopping ECT. Monotherapy with nortriptyline has limited efficacy. The combination of nortriptyline and lithium is more effective, but the relapse rate is still high, particularly during the first month of continuation therapy.

Differential occupancy of somatodendritic and postsynaptic 5HT(1A) receptors by pindolol: a dose-occupancy study with [11C]WAY 100635 and positron emission tomography in humans

Augmentation of selective serotonin reuptake inhibitors (SSRIs) therapy by the 5-HT(1A) receptor agent pindolol may reduce the delay between initiation of antidepressant treatment and clinical response. This hypothesis is based on the ability of pindolol to block 5-HT(1A) autoreceptors in the dorsal raphe nuclei (DRN) and to potentiate the increase in 5-HT transmission induced by SSRIs. However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT(1A) receptors during treatment with pindolol controlled release (CR) in nine healthy volunteers with Positron Emission Tomography and [11C]WAY 100635. Subjects were studied four times: at baseline, following one week of pindolol CR 7.5 mg/day (4 and 10 hrs post dose), and following one dose of pindolol CR 30 mg(4 hrs post dose). Occupancy of the DRN was 40 +/- 29% on scan 2, 38 +/- 26% on scan 3, and 64 +/- 15% on scan 4. The average occupancy in all other regions was significantly lower at each doses (18 +/- 5% on scan 2, 12 +/- 3% on scan 3, and 42 +/- 4% on scan 4). These results suggest that the blockade in the DRN reached in clinical studies (7.5 mg/day) might be too low and variable to consistently augment the therapeutic effect of SSRIs. However, these data indicate that pindolol exhibits in vivo selectivity for the DRN 5-HT(1A) autoreceptors. As DRN selectivity is desirable for potentiation of 5-HT function, this observation represents an important proof of concept for the development of 5-HT(1A) agents in this application.

Are suicide attempters who self-mutilate a unique population?

OBJECTIVE

Individuals who mutilate themselves are at greater risk for suicidal behavior. Clinically, however, there is a perception that the suicide attempts of self-mutilators are motivated by the desire for attention rather than by a genuine wish to die. The purpose of this study was to determine differences between suicide attempters with and without a history of self-mutilation.

METHOD

The authors examined demographic characteristics, psychopathology, objective and perceived lethality of suicide attempts, and perceptions of their suicidal behavior in 30 suicide attempters with cluster B personality disorders who had a history of self-mutilation and a matched group of 23 suicide attempters with cluster B personality disorders who had no history of self-mutilation.

RESULTS

The two groups did not differ in the objective lethality of their attempts, but their perceptions of the attempts differed. Self-mutilators perceived their suicide attempts as less lethal, with a greater likelihood of rescue and with less certainty of death. In addition, suicide attempters with a history of self-mutilation had significantly higher levels of depression, hopelessness, aggression, anxiety, impulsivity, and suicide ideation. They exhibited more behaviors consistent with borderline personality disorder and were more likely to have a history of childhood abuse. Self-mutilators had more persistent suicide ideation, and their pattern for suicide was similar to their pattern for self-mutilation, which was characterized by chronic urges to injure themselves.

CONCLUSIONS

Suicide attempters with cluster B personality disorders who have a history of self-mutilation tend to be more depressed, anxious, and impulsive, and they also tend to underestimate the lethality of their suicide attempts. Therefore, clinicians may be unintentionally misled in assessing the suicide risk of self-mutilators as less serious than it is.

Decreased regional brain metabolism after ect

OBJECTIVE

The antidepressant action of ECT may be related to its anticonvulsant properties. Positron emission tomography (PET) studies of regional cerebral metabolic rate for glucose were used to test this hypothesis.

METHOD

Ten patients with major depression were studied with PET before and approximately 5 days after a course of bilateral ECT. Statistical parametric mapping was used to identify regions of decreased cerebral glucose metabolism.

RESULTS

Widespread regions of decreased regional cerebral glucose metabolism were identified after ECT, especially in the frontal and parietal cortex, anterior and posterior cingulate gyrus, and left temporal cortex. A region-of-interest analysis similarly indicated post-ECT reductions in regional cerebral glucose metabolism.

CONCLUSIONS

ECT reduces neuronal activity in selected cortical regions, a potential anticonvulsant and antidepressant effect.

Anxiety in major depression: relationship to suicide attempts

OBJECTIVE

This study was an examination of the relationship of lifetime panic disorder and anxiety symptoms at index hospitalization to a history of a suicide attempt in patients with a major depressive episode.

METHOD

A total of 272 inpatients with at least one major depressive episode, with or without a history of a suicide attempt, were entered into the study. They were given structured diagnostic interviews for axis I and axis II disorders. Suicide attempt history, current psychopathology, and traits of aggression and impulsivity were also assessed.

RESULTS

The rates of panic disorder did not differ in the suicide attempters and nonattempters. Agitation, psychic anxiety, and hypochondriasis were more severe in the nonattempter group. A multivariate analysis confirmed that this effect was independent of aggression and impulsivity.

CONCLUSIONS

Comorbid panic disorder in patients with major depression does not seem to increase the risk for lifetime suicide attempt. The presence of greater anxiety in the nonattempters warrants further investigation.

Modulation of amphetamine-induced striatal dopamine release by ketamine in humans: implications for schizophrenia

BACKGROUND

Recent brain imaging studies have indicated that schizophrenia is associated with increased amphetamine-induced dopamine release in the striatum. It has long been hypothesized that dysregulation of subcortical dopamine systems in schizophrenia might result from a failure of the prefrontal cortex (PFC) to adequately control subcortical dopaminergic function. The activity of midbrain dopaminergic neurons is regulated, in part, by glutamatergic projections from the PFC acting via glutamatergic N-methyl-D-aspartate (NMDA) receptors. The goal of this study was to test the hypothesis that a pharmacologically induced disruption of NMDA transmission leads to an increase in amphetamine-induced dopamine release in humans.

METHODS

In eight healthy volunteers, we compared striatal amphetamine-induced (0.25 mg/kg) dopamine release under control conditions and under sustained disruption of NMDA transmission induced by infusion of the noncompetitive NMDA antagonist ketamine (0.2 mg/kg intravenous bolus followed by 0.4 mg/kg/hour intravenous infusion for 4 hours). Amphetamine-induced dopamine release was determined with single photon emission computed tomography, as the reduction in the binding potential (BP) of the radiolabeled D(2) receptor antagonist [(123)I]IBZM.

RESULTS

Ketamine significantly enhanced the amphetamine-induced decrease in [(123)I]IBZM BP, from -5.5% +/- 3.5% under control conditions to -12. 8% +/- 8.8% under ketamine pretreatment (repeated-measures analysis of variance, p =.023).

CONCLUSIONS

The increase in amphetamine-induced dopamine release induced by ketamine (greater than twofold) was comparable in magnitude to the exaggerated response seen in patients with schizophrenia. These data are consistent with the hypothesis that the alteration of dopamine release revealed by amphetamine challenge in schizophrenia results from a disruption of glutamatergic neuronal systems regulating dopaminergic cell activity.