Richard De La Garza

Richard De La Garza
University of California, Los Angeles | UCLA · Department of Psychiatry and Biobehavioural Sciences

PhD

About

195
Publications
18,017
Reads
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4,610
Citations
Additional affiliations
June 2020 - present
University of California, Los Angeles
Position
  • Professor
April 2014 - June 2019
University of Texas MD Anderson Cancer Center
Position
  • Professor (Full)
February 2013 - June 2019
Baylor College of Medicine
Position
  • Professor (Full)

Publications

Publications (195)
Article
Methamphetamine use is surging globally as a cause of morbidity and mortality. Treatment is typically sought in early abstinence, when craving and depressive symptoms are intense, contributing to relapse and poor outcomes. To advance an understanding of this problem and identify therapeutic targets, we conducted a retrospective analysis of brain st...
Article
The increased risk of alcohol use disorder (AUD) in individuals with post-traumatic stress disorder (PTSD) is well-documented. Compared to individuals with PTSD or AUD alone, those with co-existing PTSD and AUD exhibit greater symptom severity, poorer quality of life, and poorer treatment outcomes. Although the treatment of comorbid AUD is vital fo...
Article
Genetic variation in the serotonin transporter (SLC6A4) has been shown to moderate the acute subjective effects of cocaine. Methylation of the SLC6A4 gene is associated with decreased transcription of the serotonin transporter, leading to increased serotonin in the synapse. In this study, methylation of the SLC6A4 gene was investigated in the moder...
Article
Full-text available
Objective The primary objective of this study was to determine the frequency of screening instrument-detected depression and anxiety in outpatients on initial presentation to a consultation psychiatric oncology clinic. The secondary objectives were to identify characteristics associated with depression and anxiety among these patients, and to deter...
Article
Full-text available
Tinnitus is a highly prevalent medical disorder occurring in 10-30% of the general population. This disorder often becomes chronic and severe effecting quality of life contributing to significant psychiatric consequences; one that we have written about recently is comorbid insomnia. The latter can predispose effected persons to depressive episodes...
Article
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PurposeAdequate adjustment to bodily changes during various phases of cancer treatment is important to patients’ emotional well-being. The Body Image Scale (BIS) is a widely used tool for assessment of body image concerns in different cancer types. However, a cut point score indicative of clinically relevant body image concerns has not been establi...
Article
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It is increasingly accepted that higher levels of excellence and innovation in research can be achieved by organizations that promote equity, diversity, and inclusion across several domains including ethnicity and gender. The purpose of this commentary is to provide an overview of the methods used to increase diversity within ACNP, as well as recom...
Article
Full-text available
Methamphetamine (MA) is a highly addictive stimulant with recent upward trends in prevalence and associated public health problems. Drug demand, as assessed by hypothetical purchasing tasks, has been useful in addictions research and may help our understanding of the factors influencing MA use. However, no studies have assessed MA demand using curr...
Poster
Full-text available
(See page 223: PS3-122: COMPARISON OF DEMAND FOR CIGARETTES AND METHAMPHETAMINE AMONG INDIVIDUALS WITH METHAMPHETAMINE USE DISORDER)
Poster
Full-text available
(Poster 23, page 22) Comparison of demand for cigarettes and methamphetamine among individuals with methamphetamine use disorder
Article
Background and objectives: No medication has Food and Drug Administration approval for cannabis use disorder (CUD), and most medication development focuses on the withdrawal syndrome. We evaluated the effects of short-term treatment using the α-2A-adrenergic receptor agonist, guanfacine, on withdrawal symptoms in volunteers with CUD and a history...
Article
Background: Acetylcholinergic (ACh) neurons interface with the mesolimbic dopamine pathway implicated in addiction, and acetylcholinesterase inhibitors (AChEis) have been shown to reduce the immediate effects of cocaine and amount used. Our study is the first to examine if the safe and low-interaction AChEi rivastigmine (riv) alters the subjective...
Article
Background and Objectives Recent surveys confirm continued increases in the use of electronic‐cigarettes (e‐cigarettes) in adolescents and adults. Users often state that e‐cigarettes reduce tobacco craving and withdrawal symptoms in addition to their smoking. Data from laboratory studies and clinical trials have confirmed these statements, though t...
Article
The gut microbiota has recently gained attention as a possible modulator of brain activity. A number of reports suggest that the microbiota may be associated with neuropsychiatric conditions such as major depressive disorder, autism, and anxiety. The gut microbiota is thought to influence the brain via vagus nerve signaling, among other possible me...
Article
Background and objectives: The endogenous cannabinoid anandamide (AEA), an agonist at type-1 cannabinoid (CB1) receptors, is metabolized by fatty acid amide hydrolase (FAAH). The common variant rs324420 C->A within the FAAH gene on chromosome 1 codes for a missense substitution (Pro129Thr), resulting in decreased FAAH activity and increased endoca...
Article
Objective Body image is a vital and complex issue in cancer patients, but not well recognized. In the ambulatory psychiatric-oncology clinic, we assessed what portion of cancer patients endorsed appearance problems and if they differed in terms of depression, anxiety, or distress scores when compared with those who did not endorse appearance proble...
Article
Full-text available
Background: In substance-dependent individuals, drug deprivation and drug use trigger divergent behavioral responses to environmental cues. These divergent responses are consonant with data showing that short- and long-term adaptations in dopamine signaling are similarly sensitive to state of drug use. The literature suggests a drug state-dependen...
Article
Background and Objectives Delay discounting is associated with numerous clinically significant aspects of substance use disorders (SUDs). Recent studies have demonstrated that different models for assessing discounting may result in disparate conclusions. The current study compared two discounting tasks: money now versus money later (M‐M) and metha...
Article
Full-text available
Background The use of electronic cigarettes (ECs) has increased drastically over the past five years, primarily as an alternative to smoking tobacco cigarettes. However, the adverse effects of acute and long-term use of ECs on the microbiota have not been explored. In this pilot study, we sought to determine if ECs or tobacco smoking alter the oral...
Data
Correlations between the top 10 most abundant genera per sample type and the CO levels based on linear regression.
Data
Mean relative abundance of significant fecal taxa from the human cohort. Con, control; EC, electronic cigarette user, TS, tobacco smoker.
Data
Analysis of bacterial profiles based on sample type. (A) Weighted UniFrac PCoA. (B) Alpha diversity. (C) Boxplot of most significant bacterial genera. All genera in the box plot were significantly different by Kruskal-Wallis with a P < 0.001.
Data
Boxplot analysis of the bacterial genera in oral samples per exposure group. Genera ordered based on P value by reverse numerical order. All genera with >1% mean abundance included. No genera were found to be significantly different by exposure in either (A) Buccal swab or (B) Saliva.
Data
Correlations between Bacteroides and Prevotella and the CO levels in each sample type. Correlations are based on linear regression.
Article
Full-text available
Tinnitus is a prevalent medical disorder which frequently becomes chronic and severe. Furthermore, quality of life can become compromised with many experiencing comorbid insomnia. We hypothesize that insomnia is a highly prevalent symptom and diagnostic category accompanying tinnitus. Our article reviews the tinnitus literature examining the preval...
Article
Introduction: Akathisia is a common and severely disabling medication-induced movement disorder. The condition is often missed, and patients suffer for a long time until diagnosed and managed properly. It is important to bring awareness to the clinicians for early detection and management of akathisia. Methods: We reviewed four years record of p...
Article
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Breath holding (BH) endurance has been suggested as a measure of the distress tolerance that could predict the outcome of attempts to implement behavior changes, such as stopping smoking or illicit substance use. It is not known however, to what degree BH endurance is a variable trait that may vary depending on situational context, or a stable stat...
Article
It is well-documented in the literature that cocaine use is associated with neurocognitive impairment. The manner in which patterns of cocaine use, such as years of use, recent use over the past month, and daily amount of cocaine use, moderate neurocognition has been studied in a relatively piecemeal manner. Hence, the purpose of the study was to e...
Article
Objective: This study investigated variants of tryptophan hydroxylase (TPH)1, TPH2, and SLC6A4 in the moderation of the subjective effects of cocaine. Methods: Non-treatment-seeking cocaine-dependent individuals (N=66) were intravenously administered saline and cocaine (40 mg) in a randomized order. Participants self-reported subjective effects...
Article
Delay discounting describes how a reward loses value as a function of increasing delay to its receipt and has been reliably associated with a variety of vulnerable populations including those with substance use disorders (SUDs). Two commonly used models to assess delay discounting in the field of SUDs include log k derived from Mazur’s hyperbolic e...
Article
Background and objectives: Chronic cocaine use has been linked to several abnormalities in cardiac functioning. The objective of this study was to further characterize baseline heart rate and electrocardiograph (ECG) profiles of individuals with cocaine use disorder (CUD) by evaluating demographic and drug use variables that may impact cardiovascu...
Article
Objective: To determine whether premorbid IQ mediates performance on neurocognitive tests in individuals diagnosed with cocaine use disorder (CUD). Method: Recently abstinent cocaine users (N = 113) completed measures sensitive to the effects of cocaine on cognition: Conners' Continuous Performance Task-II (CPT-II), n-back working memory test, a...
Article
Full-text available
Exercise may be a useful treatment for substance use disorders. Participants (N=24) included treatment-seeking individuals with concurrent cocaine and tobacco-use disorder (cigarette smokers). Participants were randomized to either running or walking (30 min per session, 3 times per week) or sitting (control condition) for 4 consecutive weeks. Seve...
Article
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Objectives: We examined whether a functional variant of the ADRA1A gene moderated cocaine-induced subjective effects in a group of cocaine-dependent individuals. Methods: This study was a within-participant, double-blind, placebo-controlled inpatient human laboratory evaluation of 65 nontreatment-seeking, cocaine-dependent [Diagnostic and Statis...
Article
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Background: Serotonin and norepinephrine reuptake inhibitors are effective first-line agents for the treatment of posttraumatic stress disorder (PTSD), but treatment is associated with a range of side effects that limit treatment adherence. Prazosin, an α1-noradrenergic antagonist with a half-life of roughly 2-3 hours, has shown promise in the tre...
Article
Full-text available
Background: Our pilot study suggested that the angiotensin-converting enzyme inhibitor perindopril might reduce some subjective effects produced by i.v. methamphetamine. We characterized the impact of a wider range of perindopril doses on methamphetamine-induced effects in a larger group of non-treatment-seeking, methamphetamine-using volunteers....
Article
Background and objectives: The anterior cingulate cortex (ACC) is hypothesized to be involved in decision making and emotion regulation. Previous observations of drug dependent individuals indicate that substance dependence may be associated with cingulum white matter abnormalities. The present study evaluated cingulum white matter in cigarette sm...
Article
Full-text available
Current on-site drug of abuse detection methods involve invasive sampling of blood and urine specimens, or collection of oral fluid, followed by qualitative screening tests using immunochromatographic cartridges. Test confirmation and quantitative assessment of a presumptive positive are then provided by remote laboratories, an inefficient and cost...
Article
Full-text available
Background: Cholinergic transmission is altered by drugs of abuse and contributes to psychostimulant reinforcement. In particular, acetylcholinesterase inhibitors, like huperzine A, may be effective as treatments for cocaine use disorder. Methods: The current report describes results from a double-blind, placebo-controlled study in which participa...
Article
Pramipexole is a D3 dopamine receptor-preferring agonist indicated for the treatment of Parkinson disease. Studies associate pramipexole with pathological gambling and impulse control disorders suggesting a role for D3 receptors in reinforcement processes. Clinical studies showed pramipexole decreased cocaine craving and reversed central deficits i...
Article
The aim of this study was to identify gene variants of DAT1 (SLC6A3) that modulate subjective responses to acute cocaine exposure. Non-treatment-seeking volunteers (n=66) with cocaine use disorders received a single bolus infusion of saline and cocaine (40 mg, intravenous) in a randomized order. Subjective effects were assessed with visual analog s...
Article
Full-text available
Abnormal interhemispheric functional connectivity correlates with several neurologic and psychiatric conditions, including depression, obsessive-compulsive disorder, schizophrenia, and stroke. Abnormal interhemispheric functional connectivity also correlates with abuse of cannabis and cocaine. In the current report, we evaluated whether tobacco abu...
Article
Full-text available
In the present study, we tested the hypothesis that the potent and selective dopamine-β-hydroxylase (DβH) inhibitor nepicastat would have minimal effects on cardiovascular and pharmacokinetic parameters associated with cocaine administration and would reduce the positive subjective effects produced by cocaine. We conducted a double-blind, placebo-c...
Article
Current on-site drug of abuse detection methods involve invasive sampling of blood and urine specimens, or collection of oral fluid, followed by qualitative screening tests using immunochromatographic cartridges. Test confirmation and quantitative assessment of a presumptive positive are then provided by remote laboratories, an inefficient and cost...