Psychiatric symptom differences in people with schizophrenia associated with substantial lifetime substance use but no current substance use disorder

Integrative Pharmacology in the Treatment of Substance Use Disorders

The detrimental physical, mental, and socioeconomic effects of substance use disorders (SUDs) have been apparent to the medical community for decades. However, it has become increasingly urgent in recent years to develop novel pharmacotherapies to treat SUDs. Currently, practitioners typically rely on monotherapy. Monotherapy has been shown to be superior to no treatment at all for most substance classes. However, many randomized controlled trials (RCTs) have revealed that monotherapy leads to poorer outcomes when compared with combination treatment in all specialties of medicine. The results of RCTs suggest that monotherapy frequently fails since multiple dysregulated pathways, enzymes, neurotransmitters, and receptors are involved in the pathophysiology of SUDs. As such, research is urgently needed to determine how various neurobiological mechanisms can be targeted by novel combination treatments to create increasingly specific yet exceedingly comprehensive approaches to SUD treatment. This article aims to review the neurobiology that integrates many pathophysiologic mechanisms and discuss integrative pharmacology developments that may ultimately improve clinical outcomes for patients with SUDs. Many neurobiological mechanisms are known to be involved in SUDs including dopaminergic, nicotinic, N-methyl-D-aspartate (NMDA), and kynurenic acid (KYNA) mechanisms. Emerging evidence indicates that KYNA, a tryptophan metabolite, modulates all these major pathophysiologic mechanisms. Therefore, achieving KYNA homeostasis by harmonizing integrative pathophysiology and pharmacology could prove to be a better therapeutic approach for SUDs. We propose KYNA-NMDA-α7nAChRcentric pathophysiology, the "conductor of the orchestra," as a novel approach to treat many SUDs concurrently. KYNA-NMDA-α7nAChR pathophysiology may be the "command center" of neuropsychiatry. To date, extant RCTs have shown equivocal findings across comparison conditions, possibly because investigators targeted single pathophysiologic mechanisms, hit wrong targets in underlying pathophysiologic mechanisms, and tested inadequate monotherapy treatment. We provide examples of potential combination treatments that simultaneously target multiple pathophysiologic mechanisms in addition to KYNA. Kynurenine pathway metabolism demonstrates the greatest potential as a target for neuropsychiatric diseases. The investigational medications with the most evidence include memantine, galantamine, and N-acetylcysteine. Future RCTs are warranted with novel combination treatments for SUDs. Multicenter RCTs with integrative pharmacology offer a promising, potentially fruitful avenue to develop novel therapeutics for the treatment of SUDs.

Enhancing the resolution of behavioral measures: Key observations during a forty year career in behavioral neuroscience

This manuscript reviews several key observations from the research program of Professor John P. Bruno that are believed to have significantly advanced our understanding of the brain's mediation of behavior. This review focuses on findings within several important research areas in behavioral neuroscience, including a) age-dependent neurobehavioral plasticity following brain damage; b) the role of the cortical cholinergic system in attentional processing and cognitive flexibility; and c) the design and validation of animal models of cognitive deficits in schizophrenia. In selecting these observations, emphasis was given to examples in which the heuristic potency was increased by maximizing the resolution and microanalysis of behavioral assays in the same fashion as one typically refines neuronal manipulations. Professor Bruno served the International Behavioral Neuroscience Society (IBNS) as an IBNS Fellow (1995-present) and President of the IBNS (2001-02).

Potential Role of Antipsychotic-Galantamine-Memantine Combination in the Treatment of Positive, Cognitive, and Negative Symptoms of Schizophrenia

Schizophrenia is, in part, a cognitive illness. There are no approved medications for cognitive impairments associated with schizophrenia (CIAS) and primary negative symptoms. Cholinergic and glutamatergic systems, alpha-7 nicotinic acetylcholine (α-7nACh) and N-methyl-D-aspartate (NMDA) receptors, kynurenic acid (KYNA), and mismatch negativity have been implicated in the pathophysiology of CIAS and negative symptoms. Galantamine is an acetylcholinesterase inhibitor that is also a positive allosteric modulator at the α4β2 and α7nACh receptors. Memantine is a noncompetitive NMDA receptor antagonist. Galantamine and memantine alone and in combination were effective for cognition in animals and people with Alzheimer's disease. The objective of this article is to critically dissect the published randomized controlled trials with galantamine and memantine for CIAS to highlight the efficacy signal. These studies may have failed to detect a clinically meaningful efficacy signal due to limitations, methodological issues, and possible medication nonadherence. There is evidence from a small open-label study that the galantamine-memantine combination may be effective for CIAS with kynurenine pathway metabolites as biomarkers to detect the severity of cognitive impairments. Given that there are no available treatments for cognitive impairments and primary negative symptoms in schizophrenia, testing of this "five-pronged strategy" (quintuple hypotheses: dopamine, nicotinic-cholinergic, glutamatergic/NMDA, GABA, and KYNA) is a "low-risk high-gain" approach that could be a major breakthrough in the field. The galantamine-memantine combination has the potential to treat positive, cognitive, and negative symptoms, and targeting the quintuple hypotheses concurrently may lead to a major scientific advancement - from antipsychotic treatment to antischizophrenia treatment.

Can symptoms help in differential diagnosis between substance-induced vs independent psychosis in adults with a lifetime diagnosis of cocaine use disorder?

The main goal of this study it is explore the psychopathological differences between IPD and SIPD in a sample of 125 adults with a lifetime diagnosis of cocaine disorder recruited from treatment setting and through street contacts. A secondary analysis of six cross-sectional studies was conducted between 2000 and 2010. SIPD and IPD were diagnosed using the Psychiatric Research Interview for Substance and Mental Disorders (PRISM). 38 subjects (30.4%) were diagnosed with lifetime IPD and 87 (69.6%) with lifetime SIPD. A binomial logistic regression analysis using SIPD as the reference group showed that only previous prison admissions (OR 2.59; 95% CI 1.05, 6.36) and visual hallucinations (OR 5.21; 95% CI 1.54, 17.65) remained significant variables in the group with lifetime SIPD. In the group with lifetime IPD, grandiose delusions (OR 0.19; 95% CI 0.06, 0.60) and disorganized speech (OR 0.16; 95% CI 0.04, 0.61) remained significant. Model predicts the diagnosis of lifetime SIPD with a sensitivity of 80.3% and a specificity of 78.2%. This clinical profile of lifetime SIPD could help distinguish between IPD and SIPD among adults with lifetime diagnosis of cocaine disorder.