Precision medicine for psychotic disorders: objective assessment, risk prediction, and pharmacogenomics

Psychosis occurs inside the brain, but may have external manifestations (peripheral molecular biomarkers, behaviors) that can be objectively and quantitatively measured. Blood biomarkers that track core psychotic manifestations such as hallucinations and delusions could provide a window into the biology of psychosis, as well as help with diagnosis and treatment. We endeavored to identify objective blood gene expression biomarkers for hallucinations and delusions, using a stepwise discovery, prioritization, validation, and testing in independent cohorts design. We were successful in identifying biomarkers that were predictive of high hallucinations and of high delusions states, and of future psychiatric hospitalizations related to them, more so when personalized by gender and diagnosis. Top biomarkers for hallucinations that survived discovery, prioritization, validation and testing include PPP3CB, DLG1, ENPP2, ZEB2, and RTN4. Top biomarkers for delusions include AUTS2, MACROD2, NR4A2, PDE4D, PDP1, and RORA. The top biological pathways uncovered by our work are glutamatergic synapse for hallucinations, as well as Rap1 signaling for delusions. Some of the biomarkers are targets of existing drugs, of potential utility in pharmacogenomics approaches (matching patients to medications, monitoring response to treatment). The top biomarkers gene expression signatures through bioinformatic analyses suggested a prioritization of existing medications such as clozapine and risperidone, as well as of lithium, fluoxetine, valproate, and the nutraceuticals omega-3 fatty acids and magnesium. Finally, we provide an example of how a personalized laboratory report for doctors would look. Overall, our work provides advances for the improved diagnosis and treatment for schizophrenia and other psychotic disorders.

Towards precision medicine for anxiety disorders: objective assessment, risk prediction, pharmacogenomics, and repurposed drugs

Anxiety disorders are increasingly prevalent, affect people's ability to do things, and decrease quality of life. Due to lack of objective tests, they are underdiagnosed and sub-optimally treated, resulting in adverse life events and/or addictions. We endeavored to discover blood biomarkers for anxiety, using a four-step approach. First, we used a longitudinal within-subject design in individuals with psychiatric disorders to discover blood gene expression changes between self-reported low anxiety and high anxiety states. Second, we prioritized the list of candidate biomarkers with a Convergent Functional Genomics approach using other evidence in the field. Third, we validated our top biomarkers from discovery and prioritization in an independent cohort of psychiatric subjects with clinically severe anxiety. Fourth, we tested these candidate biomarkers for clinical utility, i.e. ability to predict anxiety severity state, and future clinical worsening (hospitalizations with anxiety as a contributory cause), in another independent cohort of psychiatric subjects. We showed increased accuracy of individual biomarkers with a personalized approach, by gender and diagnosis, particularly in women. The biomarkers with the best overall evidence were GAD1, NTRK3, ADRA2A, FZD10, GRK4, and SLC6A4. Finally, we identified which of our biomarkers are targets of existing drugs (such as a valproate, omega-3 fatty acids, fluoxetine, lithium, sertraline, benzodiazepines, and ketamine), and thus can be used to match patients to medications and measure response to treatment. We also used our biomarker gene expression signature to identify drugs that could be repurposed for treating anxiety, such as estradiol, pirenperone, loperamide, and disopyramide. Given the detrimental impact of untreated anxiety, the current lack of objective measures to guide treatment, and the addiction potential of existing benzodiazepines-based anxiety medications, there is a urgent need for more precise and personalized approaches like the one we developed.

Precision medicine for mood disorders: objective assessment, risk prediction, pharmacogenomics, and repurposed drugs

Mood disorders (depression, bipolar disorders) are prevalent and disabling. They are also highly co-morbid with other psychiatric disorders. Currently there are no objective measures, such as blood tests, used in clinical practice, and available treatments do not work in everybody. The development of blood tests, as well as matching of patients with existing and new treatments, in a precise, personalized and preventive fashion, would make a significant difference at an individual and societal level. Early pilot studies by us to discover blood biomarkers for mood state were promising [1], and validated by others [2]. Recent work by us has identified blood gene expression biomarkers that track suicidality, a tragic behavioral outcome of mood disorders, using powerful longitudinal within-subject designs, validated them in suicide completers, and tested them in independent cohorts for ability to assess state (suicidal ideation), and ability to predict trait (future hospitalizations for suicidality) [3-6]. These studies showed good reproducibility with subsequent independent genetic studies [7]. More recently, we have conducted such studies also for pain [8], for stress disorders [9], and for memory/Alzheimer's Disease [10]. We endeavored to use a similar comprehensive approach to identify more definitive biomarkers for mood disorders, that are transdiagnostic, by studying mood in psychiatric disorders patients. First, we used a longitudinal within-subject design and whole-genome gene expression approach to discover biomarkers which track mood state in subjects who had diametric changes in mood state from low to high, from visit to visit, as measured by a simple visual analog scale that we had previously developed (SMS-7). Second, we prioritized these biomarkers using a convergent functional genomics (CFG) approach encompassing in a comprehensive fashion prior published evidence in the field. Third, we validated the biomarkers in an independent cohort of subjects with clinically severe depression (as measured by Hamilton Depression Scale, (HAMD)) and with clinically severe mania (as measured by the Young Mania Rating Scale (YMRS)). Adding the scores from the first three steps into an overall convergent functional evidence (CFE) score, we ended up with 26 top candidate blood gene expression biomarkers that had a CFE score as good as or better than SLC6A4, an empirical finding which we used as a de facto positive control and cutoff. Notably, there was among them an enrichment in genes involved in circadian mechanisms. We further analyzed the biological pathways and networks for the top candidate biomarkers, showing that circadian, neurotrophic, and cell differentiation functions are involved, along with serotonergic and glutamatergic signaling, supporting a view of mood as reflecting energy, activity and growth. Fourth, we tested in independent cohorts of psychiatric patients the ability of each of these 26 top candidate biomarkers to assess state (mood (SMS-7), depression (HAMD), mania (YMRS)), and to predict clinical course (future hospitalizations for depression, future hospitalizations for mania). We conducted our analyses across all patients, as well as personalized by gender and diagnosis, showing increased accuracy with the personalized approach, particularly in women. Again, using SLC6A4 as the cutoff, twelve top biomarkers had the strongest overall evidence for tracking and predicting depression after all four steps: NRG1, DOCK10, GLS, PRPS1, TMEM161B, GLO1, FANCF, HNRNPDL, CD47, OLFM1, SMAD7, and SLC6A4. Of them, six had the strongest overall evidence for tracking and predicting both depression and mania, hence bipolar mood disorders. There were also two biomarkers (RLP3 and SLC6A4) with the strongest overall evidence for mania. These panels of biomarkers have practical implications for distinguishing between depression and bipolar disorder. Next, we evaluated the evidence for our top biomarkers being targets of existing psychiatric drugs, which permits matching patients to medications in a targeted fashion, and the measuring of response to treatment. We also used the biomarker signatures to bioinformatically identify new/repurposed candidate drugs. Top drugs of interest as potential new antidepressants were pindolol, ciprofibrate, pioglitazone and adiphenine, as well as the natural compounds asiaticoside and chlorogenic acid. The last 3 had also been identified by our previous suicidality studies. Finally, we provide an example of how a report to doctors would look for a patient with depression, based on the panel of top biomarkers (12 for depression and bipolar, one for mania), with an objective depression score, risk for future depression, and risk for bipolar switching, as well as personalized lists of targeted prioritized existing psychiatric medications and new potential medications. Overall, our studies provide objective assessments, targeted therapeutics, and monitoring of response to treatment, that enable precision medicine for mood disorders.

Blood biomarkers for memory: toward early detection of risk for Alzheimer disease, pharmacogenomics, and repurposed drugs

Short-term memory dysfunction is a key early feature of Alzheimer's disease (AD). Psychiatric patients may be at higher risk for memory dysfunction and subsequent AD due to the negative effects of stress and depression on the brain. We carried out longitudinal within-subject studies in male and female psychiatric patients to discover blood gene expression biomarkers that track short term memory as measured by the retention measure in the Hopkins Verbal Learning Test. These biomarkers were subsequently prioritized with a convergent functional genomics approach using previous evidence in the field implicating them in AD. The top candidate biomarkers were then tested in an independent cohort for ability to predict state short-term memory, and trait future positive neuropsychological testing for cognitive impairment. The best overall evidence was for a series of new, as well as some previously known genes, which are now newly shown to have functional evidence in humans as blood biomarkers: RAB7A, NPC2, TGFB1, GAP43, ARSB, PER1, GUSB, and MAPT. Additional top blood biomarkers include GSK3B, PTGS2, APOE, BACE1, PSEN1, and TREM2, well known genes implicated in AD by previous brain and genetic studies, in humans and animal models, which serve as reassuring de facto positive controls for our whole-genome gene expression discovery approach. Biological pathway analyses implicate LXR/RXR activation, neuroinflammation, atherosclerosis signaling, and amyloid processing. Co-directionality of expression data provide new mechanistic insights that are consistent with a compensatory/scarring scenario for brain pathological changes. A majority of top biomarkers also have evidence for involvement in other psychiatric disorders, particularly stress, providing a molecular basis for clinical co-morbidity and for stress as an early precipitant/risk factor. Some of them are modulated by existing drugs, such as antidepressants, lithium and omega-3 fatty acids. Other drug and nutraceutical leads were identified through bioinformatic drug repurposing analyses (such as pioglitazone, levonorgestrel, salsolidine, ginkgolide A, and icariin). Our work contributes to the overall pathophysiological understanding of memory disorders and AD. It also opens new avenues for precision medicine- diagnostics (assement of risk) as well as early treatment (pharmacogenomically informed, personalized, and preventive).

Panic results in unique molecular and network changes in the amygdala that facilitate fear responses

Recurrent panic attacks (PAs) are a common feature of panic disorder (PD) and post-traumatic stress disorder (PTSD). Several distinct brain regions are involved in the regulation of panic responses, such as perifornical hypothalamus (PeF), periaqueductal gray, amygdala and frontal cortex. We have previously shown that inhibition of GABA synthesis in the PeF produces panic-vulnerable rats. Here, we investigate the mechanisms by which a panic-vulnerable state could lead to persistent fear. We first show that optogenetic activation of glutamatergic terminals from the PeF to the basolateral amygdala (BLA) enhanced the acquisition, delayed the extinction and induced the persistence of fear responses 3 weeks later, confirming a functional PeF-amygdala pathway involved in fear learning. Similar to optogenetic activation of PeF, panic-prone rats also exhibited delayed extinction. Next, we demonstrate that panic-prone rats had altered inhibitory and enhanced excitatory synaptic transmission of the principal neurons, and reduced protein levels of metabotropic glutamate type 2 receptor (mGluR2) in the BLA. Application of an mGluR2-positive allosteric modulator (PAM) reduced glutamate neurotransmission in the BLA slices from panic-prone rats. Treating panic-prone rats with mGluR2 PAM blocked sodium lactate (NaLac)-induced panic responses and normalized fear extinction deficits. Finally, in a subset of patients with comorbid PD, treatment with mGluR2 PAM resulted in complete remission of panic symptoms. These data demonstrate that a panic-prone state leads to specific reduction in mGluR2 function within the amygdala network and facilitates fear, and mGluR2 PAMs could be a targeted treatment for panic symptoms in PD and PTSD patients.

Guanfacine treatment improves ADHD phenotypes of impulsivity and hyperactivity in a neurofibromatosis type 1 mouse model

Background

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a mutation in one copy of the neurofibromin gene (NF1^+/−). Even though approximately 40–60% of children with NF1 meet the criteria for attention deficit hyperactivity disorder (ADHD), very few preclinical studies, if any, have investigated alterations in impulsivity and risk-taking behavior. Mice with deletion of a single NF1 gene (Nf1^+/−) recapitulate many of the phenotypes of NF1 patients.

Methods

We compared wild-type (WT) and Nf1^+/− mouse strains to investigate differences in impulsivity and hyperactivity using the delay discounting task (DDT), cliff avoidance reaction (CAR) test, and open field. We also investigated whether treatment with the clinically effective alpha-2A adrenergic receptor agonist, guanfacine (0.3 mg/kg, i.p.), would reverse deficits observed in behavioral inhibition.

Results

Nf1^+/− mice chose a higher percentage of smaller rewards when both 10- and 20-s delays were administered compared to WT mice, suggesting Nf1^+/− mice are more impulsive. When treated with guanfacine (0.3 mg/kg, i.p.), Nf1^+/− mice exhibited decreased impulsive choice by waiting for the larger, delayed reward. Nf1^+/− mice also exhibited deficits in behavioral inhibition compared to WT mice in the CAR test by repetitively entering the outer edge of the platform where they risk falling. Treatment with guanfacine ameliorated these deficits. In addition, Nf1^+/− mice exhibited hyperactivity as increased distance was traveled compared to WT controls in the open field. This hyperactivity in Nf1^+/− mice was reduced with guanfacine pre-treatment.

Conclusions

Overall, our study confirms that Nf1^+/− mice exhibit deficits in behavioral inhibition in multiple contexts, a key feature of ADHD, and can be used as a model system to identify alterations in neural circuitry associated with symptoms of ADHD in children with NF1.

Precision medicine for suicidality: from universality to subtypes and personalization

Suicide remains a clear, present and increasing public health problem, despite being a potentially preventable tragedy. Its incidence is particularly high in people with overt or un(der)diagnosed psychiatric disorders. Objective and precise identification of individuals at risk, ways of monitoring response to treatments and novel preventive therapeutics need to be discovered, employed and widely deployed. We sought to investigate whether blood gene expression biomarkers for suicide (that is, a 'liquid biopsy' approach) can be identified that are more universal in nature, working across psychiatric diagnoses and genders, using larger cohorts than in previous studies. Such markers may reflect and/or be a proxy for the core biology of suicide. We were successful in this endeavor, using a comprehensive stepwise approach, leading to a wealth of findings. Steps 1, 2 and 3 were discovery, prioritization and validation for tracking suicidality, resulting in a Top Dozen list of candidate biomarkers comprising the top biomarkers from each step, as well as a larger list of 148 candidate biomarkers that survived Bonferroni correction in the validation step. Step 4 was testing the Top Dozen list and Bonferroni biomarker list for predictive ability for suicidal ideation (SI) and for future hospitalizations for suicidality in independent cohorts, leading to the identification of completely novel predictive biomarkers (such as CLN5 and AK2), as well as reinforcement of ours and others previous findings in the field (such as SLC4A4 and SKA2). Additionally, we examined whether subtypes of suicidality can be identified based on mental state at the time of high SI and identified four potential subtypes: high anxiety, low mood, combined and non-affective (psychotic). Such subtypes may delineate groups of individuals that are more homogenous in terms of suicidality biology and behavior. We also studied a more personalized approach, by psychiatric diagnosis and gender, with a focus on bipolar males, the highest risk group. Such a personalized approach may be more sensitive to gender differences and to the impact of psychiatric co-morbidities and medications. We compared testing the universal biomarkers in everybody versus testing by subtypes versus personalized by gender and diagnosis, and show that the subtype and personalized approaches permit enhanced precision of predictions for different universal biomarkers. In particular, LHFP appears to be a strong predictor for suicidality in males with depression. We also directly examined whether biomarkers discovered using male bipolars only are better predictors in a male bipolar independent cohort than universal biomarkers and show evidence for a possible advantage of personalization. We identified completely novel biomarkers (such as SPTBN1 and C7orf73), and reinforced previously known biomarkers (such as PTEN and SAT1). For diagnostic ability testing purposes, we also examined as predictors phenotypic measures as apps (for suicide risk (CFI-S, Convergent Functional Information for Suicidality) and for anxiety and mood (SASS, Simplified Affective State Scale)) by themselves, as well as in combination with the top biomarkers (the combination being our a priori primary endpoint), to provide context and enhance precision of predictions. We obtained area under the curves of 90% for SI and 77% for future hospitalizations in independent cohorts. Step 5 was to look for mechanistic understanding, starting with examining evidence for the Top Dozen and Bonferroni biomarkers for involvement in other psychiatric and non-psychiatric disorders, as a mechanism for biological predisposition and vulnerability. The biomarkers we identified also provide a window towards understanding the biology of suicide, implicating biological pathways related to neurogenesis, programmed cell death and insulin signaling from the universal biomarkers, as well as mTOR signaling from the male bipolar biomarkers. In particular, HTR2A increase coupled with ARRB1 and GSK3B decreases in expression in suicidality may provide a synergistic mechanistical corrective target, as do SLC4A4 increase coupled with AHCYL1 and AHCYL2 decrease. Step 6 was to move beyond diagnostics and mechanistical risk assessment, towards providing a foundation for personalized therapeutics. Items scored positive in the CFI-S and subtypes identified by SASS in different individuals provide targets for personalized (psycho)therapy. Some individual biomarkers are targets of existing drugs used to treat mood disorders and suicidality (lithium, clozapine and omega-3 fatty acids), providing a means toward pharmacogenomics stratification of patients and monitoring of response to treatment. Such biomarkers merit evaluation in clinical trials. Bioinformatics drug repurposing analyses with the gene expression biosignatures of the Top Dozen and Bonferroni-validated universal biomarkers identified novel potential therapeutics for suicidality, such as ebselen (a lithium mimetic), piracetam (a nootropic), chlorogenic acid (a polyphenol) and metformin (an antidiabetic and possible longevity promoting drug). Finally, based on the totality of our data and of the evidence in the field to date, a convergent functional evidence score prioritizing biomarkers that have all around evidence (track suicidality, predict it, are reflective of biological predisposition and are potential drug targets) brought to the fore APOE and IL6 from among the universal biomarkers, suggesting an inflammatory/accelerated aging component that may be a targetable common denominator.

Towards understanding and predicting suicidality in women: biomarkers and clinical risk assessment

Women are under-represented in research on suicidality to date. Although women have a lower rate of suicide completion than men, due in part to the less-violent methods used, they have a higher rate of suicide attempts. Our group has previously identified genomic (blood gene expression biomarkers) and clinical information (apps) predictors for suicidality in men. We now describe pilot studies in women. We used a powerful within-participant discovery approach to identify genes that change in expression between no suicidal ideation (no SI) and high suicidal ideation (high SI) states (n=12 participants out of a cohort of 51 women psychiatric participants followed longitudinally, with diagnoses of bipolar disorder, depression, schizoaffective disorder and schizophrenia). We then used a Convergent Functional Genomics (CFG) approach to prioritize the candidate biomarkers identified in the discovery step by using all the prior evidence in the field. Next, we validated for suicidal behavior the top-ranked biomarkers for SI, in a demographically matched cohort of women suicide completers from the coroner's office (n=6), by assessing which markers were stepwise changed from no SI to high SI to suicide completers. We then tested the 50 biomarkers that survived Bonferroni correction in the validation step, as well as top increased and decreased biomarkers from the discovery and prioritization steps, in a completely independent test cohort of women psychiatric disorder participants for prediction of SI (n=33) and in a future follow-up cohort of psychiatric disorder participants for prediction of psychiatric hospitalizations due to suicidality (n=24). Additionally, we examined how two clinical instruments in the form of apps, Convergent Functional Information for Suicidality (CFI-S) and Simplified Affective State Scale (SASS), previously tested in men, perform in women. The top CFI-S item distinguishing high SI from no SI states was the chronic stress of social isolation. We then showed how the clinical information apps combined with the 50 validated biomarkers into a broad predictor (UP-Suicide), our apriori primary end point, predicts suicidality in women. UP-Suicide had a receiver-operating characteristic (ROC) area under the curve (AUC) of 82% for predicting SI and an AUC of 78% for predicting future hospitalizations for suicidality. Some of the individual components of the UP-Suicide showed even better results. SASS had an AUC of 81% for predicting SI, CFI-S had an AUC of 84% and the combination of the two apps had an AUC of 87%. The top biomarker from our sequential discovery, prioritization and validation steps, BCL2, predicted future hospitalizations due to suicidality with an AUC of 89%, and the panel of 50 validated biomarkers (BioM-50) predicted future hospitalizations due to suicidality with an AUC of 94%. The best overall single blood biomarker for predictions was PIK3C3 with an AUC of 65% for SI and an AUC of 90% for future hospitalizations. Finally, we sought to understand the biology of the biomarkers. BCL2 and GSK3B, the top CFG scoring validated biomarkers, as well as PIK3C3, have anti-apoptotic and neurotrophic effects, are decreased in expression in suicidality and are known targets of the anti-suicidal mood stabilizer drug lithium, which increases their expression and/or activity. Circadian clock genes were overrepresented among the top markers. Notably, PER1, increased in expression in suicidality, had an AUC of 84% for predicting future hospitalizations, and CSNK1A1, decreased in expression, had an AUC of 96% for predicting future hospitalizations. Circadian clock abnormalities are related to mood disorder, and sleep abnormalities have been implicated in suicide. Docosahexaenoic acid signaling was one of the top biological pathways overrepresented in validated biomarkers, which is of interest given the potential therapeutic and prophylactic benefits of omega-3 fatty acids. Some of the top biomarkers from the current work in women showed co-directionality of change in expression with our previous work in men, whereas others had changes in opposite directions, underlying the issue of biological context and differences in suicidality between the two genders. With this study, we begin to shed much needed light in the area of female suicidality, identify useful objective predictors and help understand gender commonalities and differences. During the conduct of the study, one participant committed suicide. In retrospect, when the analyses were completed, her UP-Suicide risk prediction score was at the 100 percentile of all participants tested.

Understanding and predicting suicidality using a combined genomic and clinical risk assessment approach

Worldwide, one person dies every 40 seconds by suicide, a potentially preventable tragedy. A limiting step in our ability to intervene is the lack of objective, reliable predictors. We have previously provided proof of principle for the use of blood gene expression biomarkers to predict future hospitalizations due to suicidality, in male bipolar disorder participants. We now generalize the discovery, prioritization, validation, and testing of such markers across major psychiatric disorders (bipolar disorder, major depressive disorder, schizoaffective disorder, and schizophrenia) in male participants, to understand commonalities and differences. We used a powerful within-participant discovery approach to identify genes that change in expression between no suicidal ideation and high suicidal ideation states (n=37 participants out of a cohort of 217 psychiatric participants followed longitudinally). We then used a convergent functional genomics (CFG) approach with existing prior evidence in the field to prioritize the candidate biomarkers identified in the discovery step. Next, we validated the top biomarkers from the prioritization step for relevance to suicidal behavior, in a demographically matched cohort of suicide completers from the coroner's office (n=26). The biomarkers for suicidal ideation only are enriched for genes involved in neuronal connectivity and schizophrenia, the biomarkers also validated for suicidal behavior are enriched for genes involved in neuronal activity and mood. The 76 biomarkers that survived Bonferroni correction after validation for suicidal behavior map to biological pathways involved in immune and inflammatory response, mTOR signaling and growth factor regulation. mTOR signaling is necessary for the effects of the rapid-acting antidepressant agent ketamine, providing a novel biological rationale for its possible use in treating acute suicidality. Similarly, MAOB, a target of antidepressant inhibitors, was one of the increased biomarkers for suicidality. We also identified other potential therapeutic targets or biomarkers for drugs known to mitigate suicidality, such as omega-3 fatty acids, lithium and clozapine. Overall, 14% of the top candidate biomarkers also had evidence for involvement in psychological stress response, and 19% for involvement in programmed cell death/cellular suicide (apoptosis). It may be that in the face of adversity (stress), death mechanisms are turned on at a cellular (apoptosis) and organismal level. Finally, we tested the top increased and decreased biomarkers from the discovery for suicidal ideation (CADM1, CLIP4, DTNA, KIF2C), prioritization with CFG for prior evidence (SAT1, SKA2, SLC4A4), and validation for behavior in suicide completers (IL6, MBP, JUN, KLHDC3) steps in a completely independent test cohort of psychiatric participants for prediction of suicidal ideation (n=108), and in a future follow-up cohort of psychiatric participants (n=157) for prediction of psychiatric hospitalizations due to suicidality. The best individual biomarker across psychiatric diagnoses for predicting suicidal ideation was SLC4A4, with a receiver operating characteristic (ROC) area under the curve (AUC) of 72%. For bipolar disorder in particular, SLC4A4 predicted suicidal ideation with an AUC of 93%, and future hospitalizations with an AUC of 70%. SLC4A4 is involved in brain extracellular space pH regulation. Brain pH has been implicated in the pathophysiology of acute panic attacks. We also describe two new clinical information apps, one for affective state (simplified affective state scale, SASS) and one for suicide risk factors (Convergent Functional Information for Suicide, CFI-S), and how well they predict suicidal ideation across psychiatric diagnoses (AUC of 85% for SASS, AUC of 89% for CFI-S). We hypothesized a priori, based on our previous work, that the integration of the top biomarkers and the clinical information into a universal predictive measure (UP-Suicide) would show broad-spectrum predictive ability across psychiatric diagnoses. Indeed, the UP-Suicide was able to predict suicidal ideation across psychiatric diagnoses with an AUC of 92%. For bipolar disorder, it predicted suicidal ideation with an AUC of 98%, and future hospitalizations with an AUC of 94%. Of note, both types of tests we developed (blood biomarkers and clinical information apps) do not require asking the individual assessed if they have thoughts of suicide, as individuals who are truly suicidal often do not share that information with clinicians. We propose that the widespread use of such risk prediction tests as part of routine or targeted healthcare assessments will lead to early disease interception followed by preventive lifestyle modifications and proactive treatment.

Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction

We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology.

Convergent functional genomics of anxiety disorders: translational identification of genes, biomarkers, pathways and mechanisms

Anxiety disorders are prevalent and disabling yet understudied from a genetic standpoint, compared with other major psychiatric disorders such as bipolar disorder and schizophrenia. The fact that they are more common, diverse and perceived as embedded in normal life may explain this relative oversight. In addition, as for other psychiatric disorders, there are technical challenges related to the identification and validation of candidate genes and peripheral biomarkers. Human studies, particularly genetic ones, are susceptible to the issue of being underpowered, because of genetic heterogeneity, the effect of variable environmental exposure on gene expression, and difficulty of accrual of large, well phenotyped cohorts. Animal model gene expression studies, in a genetically homogeneous and experimentally tractable setting, can avoid artifacts and provide sensitivity of detection. Subsequent translational integration of the animal model datasets with human genetic and gene expression datasets can ensure cross-validatory power and specificity for illness. We have used a pharmacogenomic mouse model (involving treatments with an anxiogenic drug--yohimbine, and an anti-anxiety drug--diazepam) as a discovery engine for identification of anxiety candidate genes as well as potential blood biomarkers. Gene expression changes in key brain regions for anxiety (prefrontal cortex, amygdala and hippocampus) and blood were analyzed using a convergent functional genomics (CFG) approach, which integrates our new data with published human and animal model data, as a translational strategy of cross-matching and prioritizing findings. Our work identifies top candidate genes (such as FOS, GABBR1, NR4A2, DRD1, ADORA2A, QKI, RGS2, PTGDS, HSPA1B, DYNLL2, CCKBR and DBP), brain-blood biomarkers (such as FOS, QKI and HSPA1B), pathways (such as cAMP signaling) and mechanisms for anxiety disorders--notably signal transduction and reactivity to environment, with a prominent role for the hippocampus. Overall, this work complements our previous similar work (on bipolar mood disorders and schizophrenia) conducted over the last decade. It concludes our programmatic first pass mapping of the genomic landscape of the triad of major psychiatric disorder domains using CFG, and permitted us to uncover the significant genetic overlap between anxiety and these other major psychiatric disorders, notably the under-appreciated overlap with schizophrenia. PDE10A, TAC1 and other genes uncovered by our work provide a molecular basis for the frequently observed clinical co-morbidity and interdependence between anxiety and other major psychiatric disorders, and suggest schizo-anxiety as a possible new nosological domain.

Topographical distribution of corticotropin-releasing factor type 2 receptor-like immunoreactivity in the rat dorsal raphe nucleus: co-localization with tryptophan hydroxylase

Corticotropin-releasing factor (CRF) and CRF-related neuropeptides are involved in the regulation of stress-related physiology and behavior. Members of the CRF family of neuropeptides bind to two known receptors, the CRF type 1 (CRF₁) receptor, and the CRF type 2 (CRF₂) receptor. Although the distribution of CRF₂ receptor mRNA expression has been extensively studied, the distribution of CRF₂ receptor protein has not been characterized. An area of the brain known to contain high levels of CRF₂ receptor mRNA expression and CRF₂ receptor binding is the dorsal raphe nucleus (DR). In the present study we investigated in detail the distribution of CRF₂ receptor immunoreactivity throughout the rostrocaudal extent of the DR. CRF₂ receptor-immunoreactive perikarya were observed throughout the DR, with the highest number and density in the mid-rostrocaudal DR. Dual immunofluorescence revealed that CRF₂ receptor immunoreactivity was frequently co-localized with tryptophan hydroxylase, a marker of serotonergic neurons. This study provides evidence that CRF₂ receptor protein is expressed in the DR, and that CRF₂ receptors are expressed in topographically organized subpopulations of cells in the DR, including serotonergic neurons. Furthermore, these data are consistent with the hypothesis that CRF₂ receptors play an important role in the regulation of stress-related physiology and behavior through actions on serotonergic and non-serotonergic neurons within the DR.

Steady state and induced auditory gamma deficits in schizophrenia

Steady state auditory evoked potentials (SSAEPs) in the electroencephalogram (EEG) and magnetoencephalogram (MEG) have been reported to be reduced in schizophrenia, most consistently to frequencies in the gamma range (40 Hz and greater). The current study evaluated the specificity of this deficit over a broad range of stimulus frequencies and harmonics, the relationship between phase locking and signal power, and whether induced 40 Hz activity was also affected. SSAEPs to amplitude modulated tones from 5 to 50 Hz were obtained from subjects with schizophrenia (SZ) and healthy control subjects in 5 Hz steps. Time-frequency spectral analysis was used to differentiate EEG activity synchronized in phase across trials using Phase Locking Factor (PLF) and Mean Power (MP) change from baseline activity. In the SSAEP frequency response condition, patients with SZ showed broad band reductions in both PLF and MP. In addition, the control subjects showed a more pronounced increase in PLF with increases in power compared to SZ subjects. A noise pulse embedded in 40 Hz stimuli resulted in a transient reduction of PLF and MP at 40 Hz in control subjects, while SZ showed diminished overall PLF. Finally, induced gamma (around 40 Hz) response to unmodulated tone stimuli was also reduced in SZ, indicating that disturbances in this oscillatory activity are not confined to SSAEPs. In summary, SZ subjects show impaired oscillatory responses in the gamma range across a wide variety of experimental conditions. Reduction of PLF along with reduced MP may reflect abnormalities in the auditory cortical circuits, such as a reduction in pyramidal cell volume, spine density and alterations in GABAergic neurons.

Anxiety-like behavior is modulated by a discrete subpopulation of interneurons in the basolateral amygdala

The basolateral amygdala (BL) is a putative site for regulating anxiety, where inhibition and excitation respectively lead to decreases and increases in anxiety-like behaviors. The BL contains local networks of GABAergic interneurons that are subdivided into classes based on neurochemical content, and are hypothesized to regulate unique functional responses of local glutamatergic projection neurons. Recently it was demonstrated that lesioning a portion of the BL interneuronal population, those interneurons that express neurokinin1 receptors (NK(1r)), resulted in anxiety-like behavior. In the current study, these NK(1r) expressing cells of the BL are further phenotypically characterized, demonstrating approximately 80% co-expression with GABA thus confirming them as GABAergic interneurons. These NK(1r) interneurons also colocalize with two distinct populations of BL interneurons as defined by the neuropeptide content. Of the NK(1r) positive cells, 41.8% are also positive for neuropeptide Y (NPY) and 39.7% of the NK(1r) positive cells are also positive for cholecystokinin (CCK). In addition to enhancing the phenotypic characterization, the extent to which the NK(1r) cells of amygdala nuclei contribute to anxiety-like responses was also investigated. Lesioning the NK(1r) expressing interneurons, with a stable form of substance P (SSP; the natural ligand for NK(1r)) coupled to the targeted toxin saporin (SAP), in the anterior and posterior divisions of the BL was correlated to increased anxiety-like behaviors compared to baseline and control treated rats. Furthermore the phenotypic and regional selectivity of the lesions was also confirmed.

Exposure to an open-field arena increases c-Fos expression in a subpopulation of neurons in the dorsal raphe nucleus, including neurons projecting to the basolateral amygdaloid complex

Serotonergic systems in the dorsal raphe nucleus are thought to play an important role in the regulation of anxiety states. To investigate responses of neurons in the dorsal raphe nucleus to a mild anxiety-related stimulus, we exposed rats to an open-field, under low-light or high-light conditions. Treatment effects on c-Fos expression in serotonergic and non-serotonergic cells in the midbrain raphe nuclei were determined 2 h following open-field exposure or home cage control (CO) conditions. Rats tested under both light conditions responded with increases in c-Fos expression in serotonergic neurons within subdivisions of the midbrain raphe nuclei compared with CO rats. However, the total numbers of serotonergic neurons involved were small suggesting that exposure to the open-field may affect a subpopulation of serotonergic neurons. To determine if exposure to the open-field activates a subset of neurons in the midbrain raphe complex that projects to forebrain circuits regulating anxiety states, we used cholera toxin B subunit (CTb) as a retrograde tracer to identify neurons projecting to the basolateral amygdaloid complex (BL) in combination with c-Fos immunostaining to identify cells that responded to open-field exposure. Rats received a unilateral injection of CTb into the BL. Seven to 11 days following CTb injection rats were either, 1) exposed to an open-field in low-light conditions, 2) briefly handled or 3) left undisturbed in home cages. Dual immunostaining for c-Fos and CTb revealed an increase in the percentage of c-Fos-immunoreactive BL-projecting neurons in open-field-exposed rats compared with handled and control rats. Dual immunostaining for tryptophan hydroxylase and CTb revealed that a majority (65%) of BL-projecting neurons were serotonergic, leaving open the possibility that activated neurons were serotonergic, non-serotonergic, or both. These data are consistent with the hypothesis that exposure to anxiogenic stimuli activates a subset of neurons in the midbrain raphe complex projecting to amygdala anxiety circuits.

Chronic inhibition of GABA synthesis in the bed nucleus of the stria terminalis elicits anxiety-like behavior

The current study tested the hypothesis that chronic loss of inhibitory GABAergic tone in the bed nucleus of the stria terminalis (BNST), a region implicated in anxiety behavior, results in generalized anxiety disorder-like behaviors without panic-like responses (i.e., tachycardia, hypertension and tachypnea) following panicogenic stimuli (e.g., sodium lactate infusions). To test this hypothesis, the GABA synthesis inhibitor L-allylglycine (L-AG) or its inactive isomer D-AG was chronically infused into the BNST of male rats via osmotic mini-pumps. L-AG, but not D-AG, treated rats had increased anxiety-like behavior as measured by social interaction (SI) and elevated-plus maze paradigms. Restoring GABAergic tone, with 100pmoles/100nl of muscimol (a GABA(A) receptor agonist), in the BNST of L-AG treated rats attenuated L-AG-induced anxiety-like behavior in the SI test. To assess panic-like states, L-AG treated rats were intravenously infused with 0.5 M sodium lactate, a panicogenic agent, prior to assessing SI and cardiorespiratory responses. L-AG decreased SI duration again; however, sodium lactate did not induce panic-like cardiorespiratory responses. These findings demonstrate that GABA inhibition in the BNST elicits anxiety-like behavior without increasing sensitivity to lactate, thus suggesting a behavioral profile similar to that of generalized anxiety-like behavior rather than that of panic.

Exposure to an open-field arena increases c-Fos expression in a distributed anxiety-related system projecting to the basolateral amygdaloid complex

Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of brain structures including the basolateral amygdala. Our previous studies demonstrate that exposure of rats to an open-field in high- and low-light conditions results in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus (BLA) compared with controls. The neural mechanisms underlying the anatomically specific effects of open-field exposure on c-Fos expression in the BLA are not clear, however, it is likely that this reflects activation of specific afferent input to this region of the amygdala. In order to identify candidate brain regions mediating anxiety-induced activation of the basolateral amygdaloid complex in rats, we used cholera toxin B subunit (CTb) as a retrograde tracer to identify neurons with direct afferent projections to this region in combination with c-Fos immunostaining to identify cells responding to exposure to an open-field arena in low-light (8-13 lux) conditions (an anxiogenic stimulus in rats). Adult male Wistar rats received a unilateral microinjection of 4% CTb in phosphate-buffered saline into the basolateral amygdaloid complex. Rats were housed individually for 11 days after CTb injections and handled (HA) for 2 min each day. On the test day rats were either, 1) exposed to an open-field in low-light conditions (8-13 lux) for 15 min (OF); 2) briefly HA or 3) left undisturbed (control). We report that dual immunohistochemical staining for c-Fos and CTb revealed an increase in the percentage of c-Fos-immunopositive basolateral amygdaloid complex-projecting neurons in open-field-exposed rats compared with HA and control rats in the ipsilateral CA1 region of the ventral hippocampus, subiculum and lateral entorhinal cortex. These data are consistent with the hypothesis that exposure to the open-field arena activates an anxiety-related neuronal system with convergent input to the basolateral amygdaloid complex.

Injections of urocortin 1 into the basolateral amygdala induce anxiety-like behavior and c-Fos expression in brainstem serotonergic neurons

The amygdala plays a key role in emotional processing and anxiety-related physiological and behavioral responses. Previous studies have shown that injections of the anxiety-related neuropeptide corticotropin-releasing factor or the related neuropeptide urocortin 1 into the region of the basolateral amygdaloid nucleus induce anxiety-like behavior in several behavioral paradigms. Brainstem serotonergic systems in the dorsal raphe nucleus and median raphe nucleus may be part of a distributed neural system that, together with the basolateral amygdala, regulates acute and chronic anxiety states. We therefore investigated the effect of an acute bilateral injection of urocortin 1 into the basolateral amygdala on behavior in the social interaction test and on c-Fos expression within serotonergic neurons in the dorsal raphe nucleus and median raphe nucleus. Male rats were implanted with bilateral cannulae directed at the region of the basolateral amygdala; 72 h after surgery, rats were injected with urocortin 1 (50 fmol/100 nl) or vehicle (100 nl of 1% bovine serum albumin in distilled water). Thirty minutes after injection, a subgroup of rats from each experimental group was exposed to the social interaction test; remaining animals were left in the home cage. Two hours after injection rats were perfused with paraformaldehyde and brains were removed and processed for immunohistochemistry. Acute injection of urocortin 1 had anxiogenic effects in the social interaction test, reducing total interaction time without affecting locomotor activity or exploratory behavior. These behavioral effects were associated with increases in c-Fos expression within brainstem serotonergic neurons. In home cage rats and rats exposed to the social interaction test, urocortin 1 treatment increased the number of c-Fos-immunoreactive serotonergic neurons within subdivisions of both the dorsal raphe nucleus and median raphe nucleus. These results are consistent with the hypothesis that the basolateral amygdala and serotonergic neurons within the midbrain raphe complex are part of an integrated neural system modulating anxiety state.

Serotonergic systems associated with arousal and vigilance behaviors following administration of anxiogenic drugs

Serotonergic systems play important roles in modulating behavioral arousal, including behavioral arousal and vigilance associated with anxiety states. To further our understanding of the neural systems associated with increases in anxiety states, we investigated the effects of multiple anxiogenic drugs on topographically organized subpopulations of serotonergic neurons using double immunohistochemical staining for c-Fos and tryptophan hydroxylase combined with topographical analysis of the rat dorsal raphe nucleus (DR). Anxiogenic drugs with diverse pharmacological properties including the adenosine receptor antagonist caffeine, the serotonin 5-HT2A/2C receptor agonist m-chlorophenyl piperazine (mCPP), the alpha2-adrenoreceptor antagonist yohimbine, and the benzodiazepine receptor partial inverse agonist N-methyl-beta-carboline-3-carboxamide (FG-7142) induced increases in behavioral arousal and vigilance behaviors consistent with an increase in anxiety state. In addition, these anxiogenic drugs, excluding yohimbine, had convergent actions on an anatomically-defined subset of serotonergic neurons within the middle and caudal, dorsal subdivision of the DR. High resolution topographical analysis revealed that at the mid-rostrocaudal level, caffeine and FG-7142 had convergent effects on c-Fos expression in serotonergic neurons that were restricted to a previously undefined region, which we have named the shell region of the dorsal part of the dorsal raphe nucleus (DRDSh), that overlaps the anatomical border between the dorsal part of the dorsal raphe nucleus, the ventral part of the dorsal raphe nucleus (DRV), and the ventrolateral part of the dorsal raphe nucleus (DRVL). Retrograde tracing methods revealed that DRDSh contains large numbers of neurons projecting to the basolateral amygdaloid nucleus, a forebrain structure important for emotional appraisal and modulation of anxiety-related physiological and behavioral responses. Together these findings support the hypothesis that there is a functional topographical organization in the DR and are consistent with the hypothesis that anxiogenic drugs have selective actions on a subpopulation of serotonergic neurons projecting to a distributed central autonomic and emotional motor control system regulating anxiety states and anxiety-related physiological and behavioral responses.

Eyeblink conditioning deficits indicate timing and cerebellar abnormalities in schizophrenia

Accumulating evidence indicates that individuals with schizophrenia manifest abnormalities in structures (cerebellum and basal ganglia) and neurotransmitter systems (dopamine) linked to internal-timing processes. A single-cue tone delay eyeblink conditioning paradigm comprised of 100 learning and 50 extinction trials was used to examine cerebellar timing circuits in 13 medicated patients with schizophrenia and 13 age- and sex-matched controls. Patients with schizophrenia showed impaired learning of the conditioned response compared to controls and also greater within-subject variability in the timing of their responses. These findings are consistent with models of schizophrenia in which timing deficits underlie information-processing abnormalities and clinical features of the disorder.

Auditory event-related potential abnormalities in bipolar disorder and schizophrenia

Auditory P300 latency prolongation or amplitude reduction has been reported in patients affected by bipolar disorder and in schizophrenia. The purpose of this study was to test whether the auditory P300 and earlier event-related potential (ERP) components elicited during an auditory discrimination task could differentiate between these two disorders. Thirteen patients with manic or mixed bipolar disorder, 12 patients with schizophrenia, and 24 control subjects were evaluated. None of the subjects had a history of alcohol or substance abuse or dependence. ERPs were elicited during an auditory discrimination task in which a subject pressed a key to infrequent 1500 Hz tones interspersed amid a series of 1000 Hz tones. The amplitude and latency of N100 and P200 were measured from ERPs to non-target tones, and N200 and P300 were measured from ERPs to target tones. N100, P200 and N200 amplitudes were reduced in schizophrenia patients, but not in bipolar patients. Both bipolar disorder and schizophrenia patients showed reduced P300 amplitude and prolonged P300 latency. Amplitude reduction in the early ERP components implicates auditory processing deficits in schizophrenia. Both groups showed reductions in P300 amplitude, suggesting a disturbance of the temporal-parietal generators of this component. Prolonged P300 latency is consistent with impaired attentional processing in schizophrenia and symptomatic bipolar disorder patients.

Evaluating and treating anxiety disorders in medical settings

Anxiety disorders and medical illness present to the primary care physician as a common comorbidity. This article aims to review the literature on the prevalence of anxiety disorders in patients presenting to primary care physicians; to address the key issues in assessing the comorbid condition; and to discuss psychological and pharmacological treatment options for patients with a comorbid anxiety disorder and medical illness. Anxiety disorders are highly prevalent within the primary care population, and these disorders significantly impact the patient's course and outcome. Fortunately, primary care physicians have a variety of effective cognitive, behavioral and pharmacological interventions available for managing these patients with comorbid anxiety and medical illnesses.

Role of norepinephrine in the dorsomedial hypothalamic panic response: an in vivo microdialysis study

Blockade of gamma-aminobutyric acid-A (GABA(A)) receptors in the dorsomedial hypothalamus (DMH) elicits a panic-like response that includes increases in heart rate (HR), blood pressure (BP), respiration rate (RR), and anxiety. Norepinephrine (NE) has been postulated to be critical in regulating panic and anxiety responses. Therefore, the first study sought to determine changes in extracellular NE levels within the DMH following acute blockade of GABA(A) receptors in the DMH using in vivo microdialysis. Rats were implanted with femoral arterial catheters and microdialysis probes into the DMH. Following recovery, the DMH of conscious rats were perfused with 100, 150, or 200 microM solutions of the GABA(A) receptor antagonist bicuculline methiodide (BMI) via the microdialysis probe. HR and BP responses were recorded and the changes in extracellular levels of NE in the dialysate samples from the DMH were determined by HPLC. Rats receiving BMI injections showed dose-dependent increases in both the extracellular NE levels in the DMH as well as HR and BP. The second study was conducted to test the functional importance of NE in the DMH to the BMI-induced physiological responses. The effects of BMI microinjection into the DMH were measured at baseline and 10 days after local injection of either vehicle or two doses of 6-hydroxydopamine (6-OHDA), a neurotoxin known to lesion NE terminals. There was a significant loss of tissue NE levels as well as BMI-induced HR, BP and RR responses in the 6-OHDA-treated but not vehicle-treated rats. Thus, blockade of GABA(A) receptors in the DMH results in NE release and the presence of NE appears to be necessary for eliciting the physiological components of the panic-like responses in this region.

Summary of a National Institute of Mental Health workshop: developing animal models of anxiety disorders

RATIONALE

There exists a wide range of animal models and measures designed to assess anxiety or fearfulness. However, the relationship between these models and clinical anxiety symptoms and syndromes is unclear. The National Institute of Mental Health convened a workshop to discuss the relationship between existing behavioral models of anxiety and the clinical profile of anxiety disorders. A second goal of this workshop was to outline various approaches towards modeling components of anxiety disorders.

OBJECTIVES

To briefly describe epidemiological and behavioral manifestations of clinical anxiety syndromes and how they relate to commonly employed animal models of anxiety. To describe approaches and considerations for developing, improving, and adapting anxiety models to better understand the neurobiology of anxiety.

METHODS

Clinicians, psychiatrists and clinical and basic neuroscientists presented data exemplifying different approaches towards understanding anxiety and the role of animal models. Panel members outlined what they considered to be critical issues in developing and employing animal models of anxiety.

RESULTS

This review summarizes the discussions and conclusions of the workshop including recommendations for improving upon existing models and strategies for developing novel models.

CONCLUSIONS

The probability of developing comprehensive animal models that accurately reflect the relative influences of factors contributing to anxiety disorder syndromes is quite low. However, ample opportunity remains to better define and extend existing models and behavioral measures related to specific processes that may be disrupted in anxiety disorders and to develop new models that consider the impact of combined factors in determining anxious behaviors.

Effects of ethanol on startle responding in alcohol-preferring and -non-preferring rats

The objectives of the present study were to determine (a) if differences exist between the selectively bred alcohol-preferring (P) and -non-preferring (NP) lines of rats in the acoustic startle response (ASR) and prepulse inhibition (PPI), and (b) the effects of ethanol on these measures. Alcohol-naïve adult female P and NP rats received a single i.p. injection of saline or ethanol (0.25, 0.5, 1. 0, or 1.5 g/kg) and were placed in the startle apparatus 10 min later. After a 5-min acclimation period, rats received five alternating trials of a startle stimulus alone (SSA) (115-dB white noise) or a PPI trial (90-dB white noise preceding a 115-dB white noise). Analysis of the ASR revealed that P rats exhibited higher startle amplitudes than did NP rats with saline injections. The 0. 5-g/kg ethanol dose reduced the startle amplitude in P, but not NP, rats. The 1.0- and 1.5-g/kg ethanol doses nearly abolished the ASR in the NP line, whereas only the highest ethanol dose had this effect in the P line. Vehicle-treated P and NP rats exhibited comparable PPI levels, but only P rats showed a significant disruption (30%) at the 0.50-g/kg ethanol dose. Neither P nor NP rats were affected by ethanol treatment at the 0.25-g/kg dose. Overall, the results suggest that: (a) the difference in baseline ASR may indicate line differences in the neurocircuitry mediating this response, possibly reflecting higher innate levels of emotional reactivity in the P line; (b) the P line may be more sensitive than the NP line to the effects of ethanol in reducing emotional reactivity; and (c) low-dose ethanol may have a greater disruptive effect on sensorimotor gating mechanisms in the P than NP rat.

LY354740, a potent group II metabotropic glutamate receptor agonist prevents lactate-induced panic-like response in panic-prone rats

LY354740 is a potent and selective agonist at the group II metabotropic glutamate receptors and is shown to be an effective inhibitor of glutamate release with significant anxiolytic and drug withdrawal alleviating properties in certain animal models. Rats with chronic inhibition of GABA synthesis in the dorsomedial hypothalamus (DMH) are highly anxious and exhibit panic-like responses to peripheral lactate infusions similar to patients with panic disorder. Using these panic-prone rats, we tested the efficacy of LY354740 in preventing the lactate-induced panic-like response, comparing it to alprazolam, a clinically effective anti-panic drug. Rats were fitted with femoral arterial and venous catheters and implanted with Alzet pumps infusing the GABA synthesis inhibitor L-allylglycine into the DMH. After four days of recovery, they were confirmed to be panic-prone to lactate infusions as indicated by increases in heart rate, blood pressure, respiratory rate and "anxiety" measured in the social interaction test. Next, they were pretreated with either vehicle, LY354740 (0.3 and 0.6 mg/kg) or alprazolam (0.5 and 1.0 mg/kg) and re-challenged with lactate infusions. LY354740 treatment was equally efficacious as alprazolam in preventing lactate-induced panic attacks in this model. These data suggest that LY354740 could be a novel anti-panic drug, as effective as alprazolam in acute treatment.

Sodium lactate elicits anxiety in rats after repeated GABA receptor blockade in the basolateral amygdala

Repeated administration of the GABA(A) receptor antagonist bicuculline methiodide into the basolateral nucleus of the amygdala at doses subthreshold to eliciting a full response will eventually produce long-term 'priming', such that heart rate, blood pressure as well as anxiety are increased at the lower doses. The present study was conducted in order to determine if the long-term priming of anxiety within the basolateral nucleus is producing a condition similar to that seen in human panic disorder by testing the response elicited by i.v. lactate infusions, since lactate infusions induce a panic attack in patients with panic disorder. Male Wistar rats were fitted with femoral arterial and venous catheters and chronic microinjection cannulae into the basolateral nucleus. Repeated daily injections of a subthreshold dose of bicuculline methiodide into the basolateral nucleus for 4-5 days elicited a primed response, while the same procedure with artificial cerebrospinal fluid vehicle (a-CSF; sham-primed) had no effect. Following priming, rats received both sodium lactate infusions (0.5 N, 10 ml/kg) or 0.9% saline in a random order separated by 48 h. Heart rate and blood pressure were monitored throughout the infusion and the animals were immediately placed in the social interaction test to assess their anxiety response. Only primed and not sham-primed rats responded to a lactate infusion with significant increases in heart rate, blood pressure and experimental anxiety. Thus, rats which are primed with chronic subthreshold GABA receptor blockade in the basolateral nucleus develop a sensitivity to sodium lactate, similar to human panic disorder patients.

Acoustic startle and fear-potentiated startle in alcohol-preferring (P) and -nonpreferring (NP) lines of rats

The objective of the present study was to determine whether alcohol-preferring P and -nonpreferring NP rats differ in their acoustic startle response and in fear-potentiated startle. In Experiment 1, male P and NP rats were tested on the startle response to acoustic stimuli ranging from 90-115 dB. Experiments 2 and 3 examined fear-potentiated startle and extinction of the response. In Experiment 2, rats received two light foot shock training sessions separated by 3-4 h. Testing consisted of ten acoustic startle (115 dB) and fear-potentiated startle (light preceding the acoustic startle) presentations administered every 24 h for 9 consecutive days. To test potentiated startle learning under reduced training conditions, a single training session was administered in Experiment 3, and a single within-session extinction test of 50 startle and 50 potentiated startle trials occurred the following day. Results of Experiment 1 indicated that P and NP rats did not differ in startle at any of the acoustic intensities tested. Following fear-potentiated startle conditioning in Experiment 2, however, both acoustic startle and potentiated startle responding were consistently greater in P than NP rats over most of the first 6 test days with P rats having approximately a 100% greater acoustic startle and 50-100% greater potentiated startle response. Moreover, following a single training session in Experiment 3, only P rats showed significant fear-conditioned startle. Additionally, P rats exhibited a 50-100% elevated acoustic startle response over that observed in NP rats. Taken together, the data indicate that, although experimentally naive male P and NP rats show similar acoustic startle responses, P rats become more responsive to both startle-alone and potentiated startle stimuli following fear conditioning. The change in general startle reactivity of the P rat following aversive conditioning, along with facilitated light foot shock learning, suggests that stress exposure may be an important variable in examining associations between anxiety and alcohol drinking behavior.

Role of corticotropin-releasing factor and urocortin within the basolateral amygdala of rats in anxiety and panic responses

The amygdala is a critical temporal lobe structure involved in the expression of anxiety and stress responses. The basolateral nucleus (BLA) of the amygdala in particular, may play a key role in anxiety. Furthermore, corticotropin-releasing factor (CRF), a 41 amino acid peptide, has been strongly implicated in the regulation of stress and anxiety responses. Centrally administered CRF has been shown to increase the anxiety-like behaviors of rodents in several animal models. A recently cloned related peptide, Urocortin (Ucn), appears to have similar affinity for the CRF1 receptor, but higher affinity at the CRF2 receptor. When microinjected into the BLA, we found Ucn was substantially more potent than CRF in producing anxiogenic-like behavior as assessed in the social interaction test. Furthermore, repetitive administration of subthreshold doses of Ucn and CRF resulted in 'priming'. Once primed, these animals exhibited behavioral and cardiovascular responses to intravenous sodium lactate, a panicogenic agent in susceptible human patients. These results suggest central CRF and Ucn play a role in generating anxiety which may be similar to that seen in pathological conditions such as panic disorder.

Chorioamniotic separation after second-trimester genetic amniocentesis: importance and frequency

PURPOSE

To determine the frequency and importance of chorioamniotic separation (CAS) after second-trimester genetic amniocentesis.

MATERIALS AND METHODS

In part 1 of the study, ultrasonography (US) databases were reviewed for cases of CAS. In part 2, a study population of 388 women undergoing amniocentesis underwent directed US examination for assessment of CAS 15 minutes and/or 2 weeks after amniocentesis. CAS, when present, was graded. A control population consisted of 363 women undergoing amniocentesis in whom the membranes were not assessed.

RESULTS

In part 1, a review of 23,883 records revealed seven cases of complete CAS, with three deaths, two preterm deliveries, and one emergency cesarean section delivery due to fetal distress. In two of these cases, there were extremity deformities at birth. In part 2, CAS was present in 98 (25%) of 388 women at some point. There was no association between CAS and procedural variables. There was no substantial difference in morbidity between patients with and those without CAS, between patients with different grades of CAS, or between the study and control populations.

CONCLUSION

Small degrees of CAS are frequently present after amniocentesis but are not detected because the membranes are not specifically evaluated. Complete CAS is less frequent.

The circumventricular organs form a potential neural pathway for lactate sensitivity: implications for panic disorder

Patients with panic disorder experience panic attacks after intravenous sodium lactate infusions by an as yet unexplained mechanism. Lactate elicits a panic-like response in rats with chronic dysfunction of GABA neurotransmission in the dorsomedial hypothalamus (DMH). The circumventricular organs, organum vasculosum lamina terminalis (OVLT) and subfornical organ (SFO), are potential sites that could detect increases in plasma lactate levels and activate the DMH. To test this, we obtained baseline heart rate (HR) and blood pressure (BP) responses to lactate infusions in rats fit with femoral arterial and venous catheters. Next, unilateral chronic injection cannulae connected to an Alzet infusion pump filled with the GABA synthesis inhibitor L-allylglycine (L-AG) were implanted into the DMH. Another chronic injection cannula was implanted into the region of the OVLT, SFO, or an adjacent control site, the median preoptic area (MePOA). These rats were tested once again with lactate infusions after injection of either artificial cerebrospinal fluid (ACSF) or tetrodotoxin (TTX) into the CVO sites. Injecting TTX into the OVLT completely blocked the lactate-induced response, whereas TTX injections into the SFO or MePOA did not. Also, direct injections of lactate (100 or 500 nl) into the OVLT elicited robust anxiety-like responses in these rats. These results suggest that the OVLT may be the primary site that detects lactate infusions, activating an anxiety-like response in a compromised DMH, and provide the first neuroanatomical basis for lactate response in panic disorder.

Dissociative symptoms in panic disorder

The present study examined the prevalence and correlates of dissociative symptoms in patients with panic disorder and patients with other nonpanic anxiety disorders. A total of 56 patients with anxiety disorders (13 with panic disorder alone, 16 with comorbid panic and other anxiety, and 27 with other anxiety disorders) were assessed with structured clinical interviews and a battery of questionnaires. Although 69% of patients with panic disorder experienced depersonalization or derealization during their panic attacks, panic disorder patients were no more likely to experience dissociative experiences as assessed by the Dissociative Experience Scale than patients with other anxiety disorders. In the entire sample, the prevalence of dissociative experiences was very low and well within nonpathological ranges. The correlates of dissociative symptoms were severity of depression, social anxiety, and personality disorders. The implications of these findings for conceptualizing the nature of dissociative symptoms within an anxiety population are discussed.

Basilar artery response to hyperventilation in panic disorder

OBJECTIVE

The purpose of this study was to measure the response of basilar artery blood flow to hyperventilation in patients with panic disorder.

METHOD

Transcranial Doppler ultrasonography was used to measure basilar artery flow during rest and after hyperventilation in 16 patients with panic disorder and eight normal comparison subjects. The subjects rated their dizziness at each phase.

RESULTS

The patients with panic disorder demonstrated greater reduction in flow rates and greater increases in dizziness than the normal comparison subjects.

CONCLUSIONS

The greater basilar artery sensitivity to hyperventilation shown by panic disorder patients suggests a possible mechanism for the development of neurological symptoms during panic attacks.

Excitatory amino acid receptor antagonists block the cardiovascular and anxiety responses elicited by gamma-aminobutyric acidA receptor blockade in the basolateral amygdala of rats

Blockade of gamma-aminobutyric acid (GABAA) receptors in the anterior basolateral amygdala (BLA) with bicuculline methiodide results in an increase in heart rate, blood pressure and "anxiety" in rats. Glutamate receptors in the BLA are also reported to be involved in eliciting anxiety responses. The purpose of this study was to investigate the interaction between GABAergic inhibition and glutamatergic excitation in the BLA. Male Wistar rts were implanted with femoral arterial catheters and bilateral chronic microinjection cannulae into the BLA. Each animal was injected with either artificial cerebrospinal fluid (100 nl), bicuculline methiodide (10 pmol/100 nl) or bicuculline methiodide + one dose of an antagonist of either the N-methyl-D-aspartate receptor [AP5 (20 and 100 pmol) and dizocilpine (25 and 125 pmol)] or the non-N-methyl-D-aspartate ionotropic receptor [CNQX (10 and 50 pmol) and GYKI 52466 (50 and 250 pmol)]. Increases in heart rate, blood pressure and "anxiety" (as measured in the social interaction test) observed in rats after bicuculline methiodide injections into the BLA were blocked in a dose dependent manner with the concurrent injections of either N-methyl-D-aspartate or non-N-methyl-D-aspartate antagonists, suggesting that activation of both subtypes of glutamate ionotropic receptors may be necessary for the responses elicited by GABAA receptor blockade in the basolateral amygdala.

Excitatory amino acid receptors in the basolateral amygdala regulate anxiety responses in the social interaction test

Blocking GABA(A) receptors in the basolateral amygdala (BLA) elicits increases in heart rate (HR), blood pressure (BP) and anxiety responses by enhancing a glutamate mediated excitation. The present study was conducted to determine the role of the ionotropic glutamate receptors within the BLA in regulating HR, BP and experimental anxiety. Blocking basal glutamate excitation had no significant effect on HR or BP, but did elicit a significant anxiolytic-like effect.

Maltreatment, conscience functioning and dopamine beta hydroxylase in emotionally disturbed boys

OBJECTIVE

Identify associations among early maltreatment, sufficiencies, and psychopathological interferences in the domains of conscience functioning and low serum dopamine beta hydroxylase activity.

METHOD

Nineteen emotionally disturbed boys screened for maltreatment experiences were compared according to age at onset of maltreatment, enzyme activity, and their conscience functioning in the domain of moral valuation. They were also compared in conscience functions to 19 age and sex matched normal counterparts.

RESULTS

Subjects who endured maltreatment prior to 36 months had developmental delays and interferences with functioning in more conscience domains than those who were either spared such experiences or who endured maltreatment later in life. Subjects with low enzyme activity had significantly more interference with authority and peer valuation than subjects with high enzyme activity. Greater interference with valuation was associated with lower enzyme activity and more frequent abuse prior to 36 months.

CONCLUSIONS

Psychosocial sequelae of early maltreatment have been identified in the domains of conscience. An association has been established between pathological interference in the domain of moral valuation and a putative neurobiologic sequelae of early maltreatment. Implications for future research in the psychobiology of maltreatment are discussed.

Monoamines in the dorsomedial hypothalamus of rats following exposure to different tests of "anxiety"

1. Adult male Sprague-Dawley rats were subjected to the fear-potentiated startle, elevated plus-maze and social interaction tests and the levels of norepinephrine, dopamine and serotonin in the dorsomedial hypothalamus were determined by high-performance liquid chromatography. 2. Only rats subjected to the full fear potentiated startle test and not the other tests of anxiety or components (foot shocks or acoustic startle) of fear-potentiated startle showed significant increases in norepinephrine and dopamine levels after 24 hours. 3. A time course experiment specific for the norepinephrine changes in the dorsomedial hypothalamus of fear-potentiated startle rats revealed a significant increase in tissue content as compared to controls at both the 12 and 24 hour post-test time points. 4. Tyrosine hydroxylase activity in the dorsomedial hypothalamus of the fear-potentiated startle rats did not show a significant change from controls. 5. An in vitro release study found a significant decrease in potassium-stimulated release of norepinephrine in the dorsomedial hypothalamus as compared to controls at 24 hours post-test. 6. These results suggest that animals exposed to fear-potentiated startle and not other tests of "anxiety" have a change in tissue catecholamine levels and that the norepinephrine change may be the result of a decrease in release and not an increase in synthesis.

The effects of GABAA receptor blockade in the dorsomedial hypothalamic nucleus on corticotrophin (ACTH) and corticosterone secretion in male rats

Experiments were conducted to test if blockade of GABAA receptors in the dorsomedial hypothalamic nucleus (DMH) of rats, which is known to elicit cardiovascular and anxiety responses, would also elicit changes in the plasma levels of adrenocorticotrophic hormone (ACTH) and corticosterone. Male Sprague-Dawley rats were anesthetized with pentobarbital, fitted with femoral arterial catheters and implanted with microinjection cannulae into the DMH or the sites anterior to the DMH (i.e., closer to the paraventricular nucleus (PVN) of the hypothalamus). The rats were then injected with either artificial cerebrospinal fluid (aCSF; 100 nl) or the GABAA antagonist, bicuculline methiodide (BMI; 50 pmol in 100 nl) and their plasma samples obtained at 5, 30, 60, and 120 min after microinjection. Plasma ACTH and corticosterone were measured by using a radioimmunoassay. Rats injected with BMI, but not aCSF, into the DMH showed significant increases in heart rate (HR, 110 +/- 16 beats/min), blood pressure (BP; 30 +/- 4 mmHg), and plasma levels of both ACTH (64 +/- 10 pg/ml) and corticosterone (170 +/- 25 ng/ml) from baseline. BMI injections into the anterior sites closer to the PVN did not elicit significant increases in HR, BP, or plasma levels of ACTH and corticosterone. These results suggest that a tonic GABAA receptor-mediated inhibition system regulates a coordinated physiological and neuroendocrine response in the DMH and that this neuroendocrine response is not due to diffusion of BMI to the PVN of rats.

Dorsomedial hypothalamic GABA dysfunction produces physiological arousal following sodium lactate infusions

Since impairing gamma-aminobutyric acidA (GABAA) receptor-mediated inhibition in the dorsomedial hypothalamus (DMH) of rats elicits a panic-like response, experiments were conducted to test if rats with GABA dysfunction in the DMH would be vulnerable to precipitation of a panic-like response after intravenous sodium lactate infusions. Rats were implanted with unilateral infusion cannula into the DMH which were connected with Alzet minipumps that chronically infused (3.5 nmol/microliter /h) either a-CSF (vehicle), dl-(racemic), l-(active) or d-(inactive) isomers of allylglycine (AG), an inhibitor of GABA synthesis. Another group of rats had l-allylglycine pumps implanted in the paraventricular nucleus of the hypothalamus (PVN) as anatomical controls. Animals were tested in the social interaction (SI) test and given sodium lactate infusions (10 ml/kg/15 min) before Alzet pump implantations and on days 4, 7, and 14 after pump placement. Rats were also tested in the elevated plus-maze on treatment day 4. Chronic impairment of GABA function in the DMH and not PVN resulted in rats being more anxious in the SI test on treatment days 4, 7, and 14 and in the elevated plus-maze on day 4 compared to a-CSF and d-AG infusions. Further, rats with GABA dysfunction in the DMH, and not PVN, exhibited significant increases in heart rate and blood pressure following IV sodium lactate infusions. There were significant decreases in DMH glutamic acid decarboxylase activity and GABA content in rats receiving 7 days of dl-AG or l-AG infusions. These results indicate that chronic reduction of GABA function in the DMH leads to the development of panic-like disorder in this animal model.

Prevalence and correlates of anger attacks: a two site study

Although anger attacks have been described in depressed outpatients, they have not been well studied in other disorders. In Study 1, we examined the prevalence of anger attacks in 50 outpatients with panic disorder. In Study 2, we replicated the initial findings at an independent site and examined the specificity of anger attacks by comparing their occurrence in patients with panic disorder, patients with other non-panic anxiety disorders and patients with a depressive disorder. At both sites, we also explored the relationship between anger attacks and demographic and clinical characteristics, such as gender, presence and severity of depression, and social anxiety measures. In both sites, the prevalence of anger attacks in patients with panic disorder was approximately one-third. However, anger attacks were not unique to panic disorder, with similar rates emerging for patients with other anxiety disorders. Furthermore, patients with depressive diagnoses had twice the prevalence of anger attacks than did anxiety patients. At both sites, those with anger attacks were significantly more depressed and were likely to have either current or past history of major depression. Anger attacks were not associated with social anxiety measures, but were related to cluster B, cluster C and self-defeating personality disorder traits. Our findings support the notion that anger attacks are best conceptualized as an associated feature of depression.

Regulation of anxiety by GABAA receptors in the rat amygdala

Blockade of GABAergic inhibition in the region of the anterior basolateral amygdala (BLA) of rats elicits physiologic changes associated with a defense reaction. The present study was undertaken to determine whether GABA receptors in the BLA might be involved in regulating experimental anxiety using the social interaction (SI) and conflict test. Guide cannulae were stereotaxically implanted bilaterally in the BLA of rats for intracerebral microinjections. In the BLA, injection of the GABAA receptor antagonists bicuculline methiodide (BMI) and picrotoxin (PIC) produced anxiogenic-like effects in the SI paradigm, as did BMI injection using the conflict paradigm. Injection of the GABAA agonist muscimol (MUS) into the central nucleus of the amygdala (Ce) produced anxiolytic-like effects in the SI test. Microinjection of MUS, baclofen (GABAB agonist), 2OH-saclofen (GABAB antagonist) or strychnine (glycine antagonist) into the BLA or BMI into the Ce elicited no change in experimental anxiety as measured by the SI test. These results suggest that endogenous GABA acts tonically at GABAA receptors in the BLA to inhibit anxiety responses.

Priming of experimental anxiety by repeated subthreshold GABA blockade in the rat amygdala

Blockade of GABAA receptor function in the area of the anterior basolateral amygdala of rats elicits physiological (increases in heart rate and blood pressure) and behavioral changes similar to symptoms of human anxiety states. Repeated subthreshold blockade of GABAA receptors in this region appears to result in a long-term 'priming' of these anxiety-like responses. The present study was conducted to characterize the 'priming' of the heart rate and blood pressure responses and to test if these 'primed' animals would show increases in anxiety responses. Male Wistar rats with arterial catheters placed for physiological measurements were implanted with chronic microinjection cannulae in the anterior basolateral amygdaloid nucleus (BLA) under pentobarbital anesthesia. Repeated daily injections of a subthreshold dose of bicuculline methiodide (GABAA receptor antagonist; BMI) into the BLA elicited 'priming' of physiological responses after 3-5 injections and this response was maintained for at least 6 weeks. The primed animals also showed increased anxiogenic responses to GABAA blockade in the BLA. The 'priming' of anxiety responses were clearly elicited before kindling of seizures as measured by EEG. These results suggest that this 'priming' phenomenon may be similar to kindling and long-term potentiation. This could be one potential mechanism for developing pathological emotional responses, such as chronic, high levels of anxiety.

Serum dopamine beta hydroxylase and maltreatment in psychiatrically hospitalized boys

Fifty boys, hospitalized on a school-age and an adolescent unit in an intermediate length psychiatric hospital, were studied while off psychoactive medication to determine how serum dopamine beta hydroxylase (DBH) activity varies with different childhood maltreatment experiences. Childhood maltreatment was categorized according to onset (before 36 months old, between 36-72 months old and over 72 months old). Childhood maltreatment groups were compared with a group of psychiatrically hospitalized boys who had neither been abused nor neglected. Boys who were younger than 72 months at age of onset of maltreatment had significantly lower DBH activity than those who had experienced maltreatment later in childhood and those who had not been subjected to abuse or neglect. This difference appeared attributable to the DBH activity of school age (but not adolescent) boys who had been abused/neglected before 72 months. Boys with a principal diagnosis of conduct disorder solitary aggressive type had lower DBH activity than boys without this diagnosis regardless of whether or not they had been maltreated. Low serum DBH may be a biological sequela of maltreatment early in life that correlates with the development of conduct disorder solitary aggressive type in boys.