Self-reported paranoia during laboratory "binge" cocaine self-administration in humans

Occurrence and severity of cocaine-induced hallucinations: Two distinct phenotypes with shared clinical factors but specific genetic risk factors

Cocaine-induced transient hallucinations (CIH) are a frequent complication following cocaine intake that is associated with addiction severity.

METHODS

Two hundred and forty-two non-psychotic and Caucasian lifetime cocaine users were included in a French multicentric study. Clinical variables and dopamine pathway genotype data were extracted and tested with CIH scores using a zero-inflated binomial model, which allows for the exploration of factors associated with occurrence and severity separately.

RESULTS

Cocaine dependence (p_occurrence= 6.18 × 10^-5, p_severity= 9.25 × 10^-8), number of cocaine dependence DSM IV-Tr criteria (p_occurrence= 1.22 × 10^-7, p_severity= 5.09 × 10^-6), and frequency of intake during the worst period of misuse (p_occurrence= 8.51 × 10^-04, p_severity= 0.04) were associated with greater occurrence and higher severity of CIH. The genetic associations did not yield significant results after correction for multiple tests. However, some nominal associations of SNPs mapped to the VMAT2, DBH, DRD1, and DRD2 genes were significant. In the multivariate model, the significant variables were the number of cocaine dependence criteria, lifetime alcohol dependence, and the nominally associated SNPs.

CONCLUSION

Our study shows that CIH occurrence and severity are two distinct phenotypes, with shared clinical risk factors; however, they likely do not share the same genetic background.

Network analysis of psychotic manifestations among cocaine users

Psychotic experiences can be described along a continuum ranging from no psychotic experience at all, to clinical psychotic disorder. Any individual in the general population may encounter psychotic experiences under certain circumstances. Transient Cocaine Induced Psychotic Symptoms (TCIPS) are a well described model of such circumstances. Therefore, our aim was to use a network analysis to get a better knowledge on the architecture of previously described risk factors and how they contributed to two different measures of psychosis (psychosis proneness and transient cocaine induced psychotic symptoms) This study is a secondary analysis conducted among 180 cocaine users in addiction care centers in Paris and Paris suburb, who were evaluated with the PDI (Peters Delusion Inventory) and the SAPS-CIP (Scale for the Assessment of Psychotic Symptoms - Cocaine Induced Psychosis). Schizophrenia diagnosis was extracted from medical record. Relevant variables significantly associated with SAPS-CIP total score or PDI at the first step were included in a network analysis to better figurate their respective associations. The network centrality measures showed that the product preferentially used (crack vs cocaine) was related to TCIPS, psychosis proneness and, to a lesser extent, schizophrenia. Secondly, in this model TCIPS is a mediator between intensive cocaine use and psychosis proneness. Thirdly, this study refines the previous knowledge on heavy cannabis use being a risk factor for TCIPS. The observed link is not direct but mediated by psychosis proneness.

Associations of substance use, psychosis, and mortality among people living in precarious housing or homelessness: A longitudinal, community-based study in Vancouver, Canada

BACKGROUND

The "trimorbidity" of substance use disorder and mental and physical illness is associated with living in precarious housing or homelessness. The extent to which substance use increases risk of psychosis and both contribute to mortality needs investigation in longitudinal studies.

METHODS AND FINDINGS

A community-based sample of 437 adults (330 men, mean [SD] age 40.6 [11.2] years) living in Vancouver, Canada, completed baseline assessments between November 2008 and October 2015. Follow-up was monthly for a median 6.3 years (interquartile range 3.1-8.6). Use of tobacco, alcohol, cannabis, cocaine, methamphetamine, and opioids was assessed by interview and urine drug screen; severity of psychosis was also assessed. Mortality (up to November 15, 2018) was assessed from coroner's reports and hospital records. Using data from monthly visits (mean 9.8, SD 3.6) over the first year after study entry, mixed-effects logistic regression analysis examined relationships between risk factors and psychotic features. A past history of psychotic disorder was common (60.9%). Nonprescribed substance use included tobacco (89.0%), alcohol (77.5%), cocaine (73.2%), cannabis (72.8%), opioids (51.0%), and methamphetamine (46.5%). During the same year, 79.3% of participants reported psychotic features at least once. Greater risk was associated with number of days using methamphetamine (adjusted odds ratio [aOR] 1.14, 95% confidence interval [CI] 1.05-1.24, p = 0.001), alcohol (aOR 1.09, 95% CI 1.01-1.18, p = 0.04), and cannabis (aOR 1.08, 95% CI 1.02-1.14, p = 0.008), adjusted for demographic factors and history of past psychotic disorder. Greater exposure to concurrent month trauma was associated with increased odds of psychosis (adjusted model aOR 1.54, 95% CI 1.19-2.00, p = 0.001). There was no evidence for interactions or reverse associations between psychotic features and time-varying risk factors. During 2,481 total person years of observation, 79 participants died (18.1%). Causes of death were physical illness (40.5%), accidental overdose (35.4%), trauma (5.1%), suicide (1.3%), and unknown (17.7%). A multivariable Cox proportional hazard model indicated baseline alcohol dependence (adjusted hazard ratio [aHR] 1.83, 95% CI 1.09-3.07, p = 0.02), and evidence of hepatic fibrosis (aHR 1.81, 95% CI 1.08-3.03, p = 0.02) were risk factors for mortality. Among those under age 55 years, a history of a psychotic disorder was a risk factor for mortality (aHR 2.38, 95% CI 1.03-5.51, p = 0.04, adjusted for alcohol dependence at baseline, human immunodeficiency virus [HIV], and hepatic fibrosis). The primary study limitation concerns generalizability: conclusions from a community-based, diagnostically heterogeneous sample may not apply to specific diagnostic groups in a clinical setting. Because one-third of participants grew up in foster care or were adopted, useful family history information was not obtainable.

CONCLUSIONS

In this study, we found methamphetamine, alcohol, and cannabis use were associated with higher risk for psychotic features, as were a past history of psychotic disorder, and experiencing traumatic events. We found that alcohol dependence, hepatic fibrosis, and, only among participants <55 years of age, history of a psychotic disorder were associated with greater risk for mortality. Modifiable risk factors in people living in precarious housing or homelessness can be a focus for interventions.

Delineating the Psychic Structure of Substance Use and Addictions, from Neurobiology to Clinical Implications: Ten Years Later

The diagnosis of substance use disorder is currently based on the presence of specifically identified behavioral symptoms. In addition, other psychiatric signs and symptoms accompany addictive behavior, contributing to the full picture of patients’ psychopathologic profile. Historically, such symptoms were confined within the framework of “comorbidity”, as comorbid psychiatric disorders or personality traits. However, an alternative unitary view of the psychopathology of addiction, inclusive of related psychiatric symptoms, has been claimed, with the support of epidemiological, neurobiological, and neuropsychological evidence. In the present article, we highlight the research advancements that strengthen this unified perspective. We then give an account of our group’s definition of a specific SCL-90-based construct of the psychopathology of addiction. Lastly, we discuss the benefits that can be expected to be acquired in the evaluation and treatment of patients with a longitudinal approach including psychological/psychiatric predisposing features, addictive behavior, and psychiatric manifestations.

A comparison of psychotic symptoms in subjects with methamphetamine versus cocaine dependence

RATIONALE

The psychostimulant drugs cocaine and methamphetamine are potent indirect dopamine receptor agonists which act through similar but not identical mechanisms. Studies in humans have observed that a large proportion of those who chronically use these drugs experience psychotic symptoms. However, direct comparisons of psychotic symptom severity between cocaine and methamphetamine users are lacking.

OBJECTIVES

The goal of the present study was to directly compare severity of psychotic symptoms between cocaine- and methamphetamine-dependent individuals. Additionally, we sought to determine how concurrent cocaine + methamphetamine dependence would influence psychotic symptoms.

METHODS

We recruited 153 polysubstance-using subjects meeting DSM-IV-TR criteria for cocaine dependence, 38 with methamphetamine dependence, and 32 with cocaine + methamphetamine dependence. Psychotic symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) and analyzed using a five-factor model. All participants were also assessed for physical and mental illnesses as well as recent substance use. Most subjects completed a comprehensive neurocognitive battery.

RESULTS

While all three groups exhibited high total PANSS scores, the positive symptom subscale was significantly higher in the methamphetamine-dependent (17.03 ± 6.3) than the cocaine-dependent group (13.51 ± 4.12) and non-significantly higher (p = 0.08) than the cocaine + methamphetamine group (14.44 ± 5.50). Groups also differed on demographic variables, viral infection, and other indices of substance use, which were unlikely to account for the difference in positive symptoms. There were only modest differences between groups in neurocognitive function.

CONCLUSIONS

Methamphetamine dependence was associated with more severe positive symptoms of psychosis than cocaine dependence. Concurrent cocaine + methamphetamine dependence did not increase psychosis severity.

Factors affecting severity of positive and negative symptoms of psychosis in a polysubstance using population with psychostimulant dependence

Approximately half of psychostimulant users experience psychotic symptoms, which include both positive and negative symptoms. Prior reports have exclusively used positive symptoms to characterize psychostimulant associated psychosis. Symptoms vary dramatically in severity, though most investigations categorize psychosis as a dichotomous occurrence. To explore the association between different substances of abuse and the severity of psychotic symptoms, we investigated 171 individuals meeting DSM-IV-TR criteria for psychostimulant (cocaine or methamphetamine) dependence in an observational cross-sectional study. Participants were predominantly male (72.5%), recruited from a socially disadvantaged neighborhood in Vancouver, Canada, with a mean age of 45.5(±8.8) years. Of the total sample, 85% were dependent on cocaine, and 28.1% were dependent on methamphetamine. Participants had a median total PANSS score of 63, ranging from 37 to 111. Demographic information, current substance use and early substance exposure were used to predict positive and negative psychotic symptom severity in linear regression models. Increased severity of positive psychotic symptoms was significantly related to greater methamphetamine and marijuana use in the past 28 days, and methadone-abstinence. Negative symptom severity was related to increased opioid use in the past 28 days. There was no overlap between predictors of positive and negative symptom severity.

Effects of levodopa-carbidopa-entacapone and smoked cocaine on facial affect recognition in cocaine smokers

In addition to difficulties in daily social functioning, regular cocaine users have decrements in social processing (the cognitive and affective processes underlying social behavior) relative to non-users. Little is known, however, about the effects of clinically-relevant pharmacological agents, such as cocaine and potential treatment medications, on social processing in cocaine users. Such drug effects could potentially alleviate or compound baseline social processing decrements in cocaine abusers. Here, we assessed the individual and combined effects of smoked cocaine and a potential treatment medication, levodopa-carbidopa-entacapone (LCE), on facial emotion recognition in cocaine smokers. Healthy non-treatment-seeking cocaine smokers (N = 14; two female) completed this 11-day inpatient within-subjects study. Participants received LCE (titrated to 400mg/100mg/200mg b.i.d.) for five days with the remaining time on placebo. The order of medication administration was counterbalanced. Facial emotion recognition was measured twice during target LCE dosing and twice on placebo: once without cocaine and once after repeated cocaine doses. LCE increased the response threshold for identification of facial fear, biasing responses away from fear identification. Cocaine had no effect on facial emotion recognition. Results highlight the possibility for candidate pharmacotherapies to have unintended impacts on social processing in cocaine users, potentially exacerbating already existing difficulties in this population.

An international perspective and review of cocaine-induced psychosis: a call to action

Cocaine use can induce transient psychotic symptoms that include suspiciousness, paranoia, hallucinations, and other cocaine-related behaviors. In this commentary, the authors provide an international perspective while reviewing the recent advances in epidemiology, clinical features, and risk factors related to cocaine-induced psychosis exhibited by patients with cocaine use disorders. In some settings, the occurrence of cocaine-induced psychosis has been shown to be as high as 86.5%. Many risk factors have been linked with cocaine-induced psychosis, including the quantity of cocaine consumed, lifetime amount of cocaine use, onset of cocaine dependence, years of use, routes of administration, other substance use disorder comorbidity, weight, gender, comorbidity with other medical and mental health disorders, genetics, and pharmacological interactions. Research has shown that the evaluation of cocaine-induced psychosis in patients with cocaine use is clinically relevant, especially in those patients who consume high amounts of cocaine, have a cannabis dependence history, have antisocial personality disorder, use administration routes other than intranasal, or exhibit attention-deficit/hyperactivity disorder (ADHD) comorbidity. Currently, the literature lacks information regarding the evolution of cocaine dependence or cocaine-dependent patients' risk for developing schizophrenia or other psychotic disorders. Furthermore, clinicians still do not have an evidence-based pharmacological approach to management of cocaine dependence available to them. Additional research is also needed regarding risk factors such as neurobiological markers and personality traits. Finally, we recommend the development of an integrative model including all of the risk factors and protective factors for cocaine-induced psychosis.

Childhood trauma are not associated with the intensity of transient cocaine induced psychotic symptoms

A personal history of childhood trauma has been associated with the severity of psychotic symptoms in several disorders. We evaluated retrospectively cocaine-induced psychotic symptoms with the SAPS-CIP and childhood trauma with the CTQ in a clinical sample of 144 cocaine users. The SAPS-CIP score was not statistically associated with the presence or number or intensity of trauma, but was associated with rapid routes of administration (intravenous and smoked) and with frequent cocaine use.

Neuroticism associated with cocaine-induced psychosis in cocaine-dependent patients: a cross-sectional observational study

BACKGROUND

Cocaine consumption can induce transient psychotic symptoms, which has been correlated with more severe addiction and aggressive behavior. However, little is known about the nature of the relationship between personality traits and psychotic symptoms in cocaine-dependent patients. This study examined the relationship between neuroticism and cocaine-induced psychosis.

METHODS

A total of 231 cocaine-dependent patients seeking treatment were recruited to the study. Personality was evaluated by the Zuckerman-Kuhlman Personality Questionnaire. Cocaine-induced psychosis questionnaire, SCID-I, and SCID-II were used to evaluate comorbidity and clinical characteristics. Data analysis was performed in three steps: descriptive, bivariate, and multivariate analyses.

RESULTS

Cocaine-induced psychosis was reported in 65.4% of the patients and some personality disorder in 46.8%. Two personality dimensions (Neuroticism-Anxiety and Aggression-Hostility) presented a significant effect on the risk of experiencing psychotic symptoms (t(229) = 2.69, p = 0.008; t(229) = 2.06, p = 0.004), and patients with psychotic symptoms showed higher scores in both variables. On the multivariate analysis, only Neuroticism remained as a significant personality factor independently associated with psychotic symptoms (Wald = 7.44, p<0.05, OR = 1.08, CI 95% 1.02-1.16) after controlling for age, gender and number of consumption substances.

CONCLUSIONS

An association between high neuroticism scores and presence of psychotic symptoms induced by cocaine has been found, independently of other consumption variables. Personality dimensions should be evaluated in cocaine-dependent patients in order to detect high scores of neuroticism and warn patients about the risk of developing cocaine-induced psychotic symptoms.

Clinical features of methamphetamine-induced paranoia and preliminary genetic association with DBH-1021C→T in a Thai treatment cohort

AIMS

To explore the clinical features of methamphetamine-induced paranoia (MIP) and associations between MIP and a genetic polymorphism in dopamine β-hydroxylase (DBH-1021C→T).

DESIGN

Retrospective analysis of clinical presentation and genetic association by χ(2) test and logistic regression analysis.

SETTING

A Thai substance abuse treatment center.

PARTICIPANTS

A total of 727 methamphetamine-dependent (MD) individuals.

MEASUREMENTS

Clinical: Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) and the Methamphetamine Experience Questionnaire (MEQ). Genetic: DBH-1021C→T.

FINDINGS

Forty per cent of individuals (289 of 727; 39.8%) with MD had MIP. Within-binge latency to MIP onset occurred more rapidly in the most recent compared with initial MIP episode (P = 0.02), despite unchanging intake (P = 0.89). Individuals with MIP were significantly less likely to carry lower (TT/CT) compared with higher (CC) activity genotypes (34.3 versus 43.3%; χ(2) 1  = 5, P = 0.03). DBH effects were confirmed [odds ratio (OR) = 0.7, P = 0.04] after controlling for associated clinical variables (MD severity, OR = 3.4, P < 0.001; antisocial personality disorder, OR = 2.2, P < 0.001; alcohol dependence, OR = 1.4, P = 0.05; and nicotine dependence, OR = 1.4, P = 0.06). TT/CT carriers were more likely to initiate cigarette smoking (OR = 3.9, P = 0.003) and probably less likely to be dependent on alcohol (OR = 0.6, P = 0.05).

CONCLUSIONS

Among methamphetamine-dependent individuals, paranoia appears to occur increasingly rapidly in the course of a session of methamphetamine use. Severity of methamphetamine dependence and antisocial personality disorder predicts methamphetamine-induced paranoia. The genetic polymorphism in dopamine β-hydroxylase is associated with methamphetamine-induced paranoia and influences smoking initiation.

Clinical differences between cocaine-induced psychotic disorder and psychotic symptoms in cocaine-dependent patients

The aim of this study is to compare the clinical characteristics of three groups of patients in treatment for cocaine dependence: patients without any psychotic symptoms (NS), patients with transient psychotic symptoms (PS) and patients with cocaine-induced psychotic disorder (CIPD). An observational and retrospective study of 150 cocaine-dependent patients undergoing treatment in the Drug Unit of the Psychiatry Department of University Hospital Vall d׳Hebron in Barcelona (Spain) using these three groups, NS, PS and CIPD, was performed. All patients were evaluated with the PRISM interview. ANOVA, χ2 tests and multivariate multinomial regression analysis were used to perform statistical analyses. Seven patients with a primary psychotic disorder were discharged. Forty-six patients (32.1%) did not report any psychotic symptoms. Ninety-seven patients (67.9%) presented with a history of any cocaine-induced psychotic symptom and were considered as the cocaine-induced psychotic (CIP) group. Among them, 39 (27.3%) were included in the PS group and 58 (40.6%) were included in the CIPD group. A history of imprisonment was found significantly more frequently in the PS group than in the NS group. The distribution of age at onset of dependence, lifetime cannabis abuse or dependence and imprisonment were significantly different between the NS and CIPD groups. We conclude that in cocaine-dependent patients, clinicians should be advised about the risk of development of psychotic symptoms. The presence of some psychotic symptoms could increase the potential risks of disturbing behaviours.

Psychotic symptoms of cocaine self-injectors in a harm reduction program

BACKGROUND

Psychotic symptoms are common among cocaine users.

METHODS

An observational naturalistic study on the effects and events of intravenous cocaine use in a drug consumption room was carried out; the patients were diagnosed of cocaine dependence (according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision).

RESULTS

Twenty-one patients, 81% men self-injected cocaine 375 times. Psychotic symptoms were observed in 62% of the patients and 21% of the self-injections; delusions were observed in 9.3%, psychotic self-reference with insight in 9.1%, illusions in 6.4%, and hallucinations in 5.3%. A higher presence of psychotic symptoms was noted with cannabis used in the previous month (76.9% versus 44.4%; P = .001) (no psychotic symptoms group); also, a greater use of benzodiazepines was observed: 75.6% versus 63.6% (P = .046). Lower use of methadone in the group with psychosis was observed: 75.6% versus 97.3% (P = .001). Motor alterations were tremor 58%, stereotyped movements 24%, and behaviour alteration 6%, significantly more frequent in the psychotic group.

CONCLUSIONS

Thus, there was a high frequency of psychotic symptoms after intravenous cocaine use; patients with psychotic symptoms reported higher use of cannabis and benzodiazepines in the previous month and lower use of methadone. More tremors and stereotyped movements were observed in the group with psychotic symptoms. It is necessary to give a special approach to cocaine intravenous users.

The α-endomannosidase gene (MANEA) is associated with panic disorder and social anxiety disorder

Unbiased genome-wide approaches can provide novel insights into the biological pathways that are important for human behavior and psychiatric disorder risk. The association of α-endomannosidase gene (MANEA) variants and cocaine-induced paranoia (CIP) was initially described in a study that used a whole-genome approach. Behavioral effects have been reported for other mannosidase genes, but MANEA function in humans and the clinical potential of the previous findings remain unclear. We hypothesized that MANEA would be associated with psychiatric phenotypes unrelated to cocaine use. We used a multi-stage association study approach starting with four psychiatric disorders to show an association between a MANEA single-nucleotide polymorphism (SNP; rs1133503) and anxiety disorders. In the first study of 2073 European American (EA) and 2459 African American subjects mostly with comorbid drug or alcohol dependence, we observed an association in EAs of rs1133503 with panic disorder (PD) (191 PD cases, odds ratio (OR)=1.7 (95% confidence interval (CI): 1.22-2.41), P=0.002). We replicated this finding in an independent sample of 142 PD cases (OR =1.53 (95% CI: 1.00-2.31), P=0.043) and extended it in an independent sample of 131 generalized social anxiety disorder cases (OR=2.15 (95% CI: 1.27-3.64), P=0.004). MANEA alleles and genotypes were also associated with gene expression differences in whole blood cells. Using publically available data, we observed a consistent effect on expression in brain tissue. We conclude that pathways involving α-endomannosidase warrant further investigation in relation to anxiety disorders.

Cocaine-induced psychotic disorders: presentation, mechanism, and management

Cocaine, the third mostly commonly used illicit drug in the United States, has a wide range of neuropsychiatric effects, including transient psychotic symptoms. When psychotic symptoms occur within a month of cocaine intoxication or withdrawal, the diagnosis is cocaine-induced psychotic disorder (CIPD). Current evidence suggests those with CIPD are likely to be male, have longer severity and duration of cocaine use, use intravenous cocaine, and have a lower body mass index. Differentiating CIPD from a primary psychotic disorder requires a detailed history of psychotic symptoms in relation to substance use and often a longitudinal assessment. Treatment includes providing a safe environment, managing agitation and psychosis, and addressing the underlying substance use disorder. This review begins with a clinical case and summarizes the literature on CIPD, including clinical presentation, differential diagnosis, mechanism and predictors of illness, and treatment.

A single-day paradigm of self-regulated human cocaine administration

Prior work by our group has shown the feasibility, safety, and validity of a multi-day, multi-dose paradigm of self-regulated cocaine administration in humans. The current work sought to consolidate these methods in a single-day design focused on reducing logistical complexity, decreasing research burden to human subjects, and increasing suitability for medication development designs.

METHODS

Eleven experienced cocaine users participated in a 6-hour, single-day design, consisting of one safety/eligibility and three experimental cocaine periods (during which subjects were allowed to self-administer 8, 16, and 32 mg/70 kg cocaine doses under a fixed-ratio 1:5 minute timeout schedule). Changes in cocaine-induced cardiovascular response, self-administration behavior, and subjective effects were assessed.

RESULTS

Procedures were well tolerated by participants, and no significant adverse events were noted. Significant (p < 0.05), changes in measures of cocaine self-administration (e.g., responses, infusions, interinfusion intervals, consumption, and plasma levels), cardiovascular response (HR), and subjective effects (“high”) were observed. In contrast, cocaine-induced increases in other vital signs (e.g., SBP, DBP) and subjective effect measures (e.g., paranoia) did not differ between doses.

CONCLUSIONS

These data support the safety, tolerability and validity of our single-day design. Depending on the application, such methods may afford advantages for assessing the self-regulation of cocaine administration behavior in humans (e.g., including medication development designs).

Cocaine-induced psychotic symptoms in French cocaine addicts

Cocaine use is known to induce transient psychotic symptoms. We evaluated retrospectively the lifetime prevalence of cocaine-induced psychotic symptoms in 105 cocaine addicts with the French version of the Scale for Assessment of Positive Symptoms-Cocaine Induced Psychosis (SAPS-CIP) in a clinical setting. Most patients (86.5%) described such symptoms.

Neuropsychological effects associated with recreational cocaine use

RATIONALE

Recent evidence suggests that recreational cocaine use is on the increase, with the UK reporting one of the highest levels of use in the EU (EMCDDA 2010). Nevertheless, very few studies have addressed the neuropsychological effects associated with non-dependent recreational cocaine use.

OBJECTIVES

The current study aimed to assess whether recreational cocaine users show neuropsychological deficits on a battery of tests, previously shown to be sensitive to cocaine-dependent and psychosis-prone individuals. Schizotypal traits were also measured.

METHODS

Recreational cocaine users (n = 17) were compared with controls (n = 24) on drug use patterns, the General Health Questionnaire, the Brief Schizotypal Personality Questionnaire (SPQ-B) and four neuropsychological tasks: spatial working memory, intra/extra-dimensional set shifting, the Stocking of Cambridge and the rapid visual processing.

RESULTS

Relative to controls, recreational cocaine users produced significantly more errors on the intra/extra-dimensional set shift task and completed fewer stages, made significantly more six box stage errors on the spatial working memory task, and made significantly more errors and fewer hits, with overall poorer detection rates on the rapid visual processing task. Recreational cocaine users reported significantly higher scores on the cognitive perceptual and disorganised thinking SPQ-B subscales and total SPQ-B scores compared to controls.

CONCLUSIONS

Recreational cocaine users displayed impairments on tasks tapping sustained attention, attentional shifting and spatial memory and reported higher schizotypal trait expression. These findings are consistent with the emerging literature suggesting subtle cognitive deficits, putatively reflecting underlying dopaminergic dysfunction, in non-dependent, recreational cocaine users.

Risk factors for cocaine-induced psychosis in cocaine-dependent patients

Cocaine consumption can induce transient psychotic symptoms, expressed as paranoia or hallucinations. Cocaine induced psychosis (CIP) is common but not developed in all cases. This is the first European study on the relationship between CIP, consumption pattern variables and personality disorders. We evaluated 173 cocaine-dependent patients over 18 years; mostly males, whose average age was 33.6 years (SD = 7.8). Patients attending an outpatient addictions department were enrolled in the study and subsequently systematically evaluated using SCID I and SCID II interviews for comorbid disorders, a clinical interview for psychotic symptoms and EuropASI for severity of addiction. A high proportion of cocaine dependent patients reported psychotic symptoms under the influence of cocaine (53.8%), the most frequently reported being paranoid beliefs and suspiciousness (43.9%). A logistic regression analysis was performed, finding that a model consisting of amount of cocaine consumption, presence of an antisocial personality disorder and cannabis dependence history had 66.2% sensitivity 75.8% specificity predicting the presence of CIP. In our conclusions, we discuss the relevance of evaluating CIP in all cocaine dependent-patients, and particularly in those fulfilling the clinical profile derived from our results. These findings could be useful for a clinical approach to the risks of psychotic states in cocaine-dependent patients.

Prospective assessment of transient cocaine-induced psychotic symptoms in a clinical setting

Cocaine use is associated with the occurrence of transient psychotic symptoms. Sixteen poly-substance abusers already in treatment, who were diagnosed with crack dependence, were assessed twice: at baseline and after 3 weeks of medical management specifically aimed at cocaine abstinence. The psychotic symptoms were assessed with the French version of the Scale for Assessment of Positive Symptoms-Cocaine-Induced Psychosis (SAPS-CIP). There was a decrease of both cocaine intake and psychotic symptoms at week 3 (Wilcoxon's Z, p < .001 and .028, respectively). Furthermore, there was a significant correlation between psychotic symptoms and dose reduction (r(2) = .49, Spearman's ρ= .613, p < .012).

Quality of life, needs, and interest among cocaine users: differences by cocaine use intensity and lifetime severity of addiction to cocaine

We examined the quality of life (QoL) of 149 patients who were recruited in 2005 at outpatient treatment centers for cocaine dependence in Spain. Important life areas and life areas with potential need and interest to change in order to improve the QoL were analyzed in terms of patients? cocaine use intensity within the previous six months and lifetime severity addiction to cocaine. The Spanish versions of the Drug User Quality of Life Scale and the Lifetime Severity Index for Cocaine were used to measure QoL, needs and interest, and severity addiction to cocaine. The data analysis employed t-tests, linear regression, Mann?Whitney U tests, multivariate regression, and chi-square tests. Tailoring treatment programs to address the life areas that are considered relevant to cocaine users considering their intensity of consumption and lifetime severity addiction to cocaine may improve retention and treatment outcomes. Further research needs to consider patients of different ethnic backgrounds and cultural contexts. The study's limitations are noted.

Toward a neurobiology of delusions

Delusions are the false and often incorrigible beliefs that can cause severe suffering in mental illness. We cannot yet explain them in terms of underlying neurobiological abnormalities. However, by drawing on recent advances in the biological, computational and psychological processes of reinforcement learning, memory, and perception it may be feasible to account for delusions in terms of cognition and brain function. The account focuses on a particular parameter, prediction error--the mismatch between expectation and experience--that provides a computational mechanism common to cortical hierarchies, fronto-striatal circuits and the amygdala as well as parietal cortices. We suggest that delusions result from aberrations in how brain circuits specify hierarchical predictions, and how they compute and respond to prediction errors. Defects in these fundamental brain mechanisms can vitiate perception, memory, bodily agency and social learning such that individuals with delusions experience an internal and external world that healthy individuals would find difficult to comprehend. The present model attempts to provide a framework through which we can build a mechanistic and translational understanding of these puzzling symptoms.

Delineating the psychic structure of substance abuse and addictions: should anxiety, mood and impulse-control dysregulation be included?

Current "official" nosology (e.g. DSM IV) is largely limited to physical manifestations of addiction that can be objectively observed and are suited to the maintaining of an "atheoretical" perspective. However, addicted subjects display additional psychiatric symptoms that affect their well-being and social functioning and, in accordance with DSM IV, are typically relegated to the domain of psychiatric "comorbidity." We contend that the relationship of these psychiatric symptoms with addiction is very close, as demonstrated by the high frequency of association observed. We further assert that substance use may modify pre-existing psychic structures such as temperament and related subthreshold conditions and lead to addiction as a specific mental disorder, inclusive also of symptoms pertaining to mood/anxiety, or impulse-control dimensions. The present contribution addresses the weaknesses of the current DSM-based nosology of addiction-related mental comorbidity. We highlight the overlap of the biological substrates and the neurophysiology of addictive processes and psychiatric symptoms associated with addiction, and propose the inclusion of specific mood, anxiety, and impulse-control dimensions in the psychopathology of addictive processes. We postulate that addiction reaches beyond the mere result of drug-elicited effects on the brain and cannot be peremptorily equated only with the use of drugs despite the adverse consequences produced. We infer that mood, anxiety and impulse-control dysregulation is at the very core of both the origins and clinical manifestations of addiction and should be incorporated into the nosology of the same, emphasising how addiction is a relapsing chronic condition in which psychiatric manifestations play a crucial role. To conclude, addictionology cannot be severed from its psychopathological connotations, in view of the undeniable presence of symptoms, of their manifest contribution to the way addicted patients feel and behave, and to the role they play in maintaining the continued use of substances.

Subtyping patients with heroin addiction at treatment entry: factor derived from the Self-Report Symptom Inventory (SCL-90)

BACKGROUND

Addiction is a relapsing chronic condition in which psychiatric phenomena play a crucial role. Psychopathological symptoms in patients with heroin addiction are generally considered to be part of the drug addict's personality, or else to be related to the presence of psychiatric comorbidity, raising doubts about whether patients with long-term abuse of opioids actually possess specific psychopathological dimensions.

METHODS

Using the Self-Report Symptom Inventory (SCL-90), we studied the psychopathological dimensions of 1,055 patients with heroin addiction (884 males and 171 females) aged between 16 and 59 years at the beginning of treatment, and their relationship to age, sex and duration of dependence.

RESULTS

A total of 150 (14.2%) patients with heroin addiction showed depressive symptomatology characterised by feelings of worthlessness and being trapped or caught; 257 (24.4%) had somatisation symptoms, 205 (19.4%) interpersonal sensitivity and psychotic symptoms, 235 (22.3%) panic symptomatology, 208 (19.7%) violence and self-aggression. These dimensions were not correlated with sex or duration of dependence. Younger patients with heroin addiction were characterised by higher scores for violence-suicide, sensitivity and panic anxiety symptomatology. Older patients with heroin addiction showed higher scores for somatisation and worthlessness-being trapped symptomatology.

CONCLUSIONS

This study supports the hypothesis that mood, anxiety and impulse-control dysregulation are the core of the clinical phenomenology of addiction and should be incorporated into its nosology.

Adolescent cannabis use increases risk for cocaine-induced paranoia

Cannabis can produce and/or exacerbate psychotic symptoms in vulnerable individuals. Early exposure to cannabis, particularly in combination with genetic factors, increases the risk of a subsequent, primary, psychotic disorder. Because paranoia is a common feature of stimulant abuse and cocaine-dependent individuals frequently endorse a history of cannabis abuse, we examined whether early cannabis exposure, in conjunction with polymorphic variation in the catechol-O-methyl transferase gene (COMT Val158Met), influences the risk for cocaine-induced paranoia (CIP).

METHODS

Cannabis-use history was obtained in 1140 cocaine-dependent individuals from a family-based (affected sibling pair) study using the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA). Logistic regression and generalized estimating equations' analyses were used to examine the role of adolescent-onset cannabis use (< or =15 years of age) on CIP risk, both controlling for previously implicated CIP risk factors and familial relationships, and considering potential interactions with COMT Val158Met genotype.

RESULTS

Cocaine-dependent individuals who endorsed CIP had significantly higher rates of adolescent-onset cannabis use than those without CIP (62.2% vs. 50.2%; chi(2)=15.2, df=1, p<0.0001), a finding that remained after controlling for sibling correlations and other risk factors. There were no effects of COMT genotype or genotype by early cannabis onset interactions. A modest (OR=1.4) and nearly significant (p=0.053) effect of CIP status in probands on CIP status in siblings was also noted.

CONCLUSIONS

Adolescent-onset cannabis use increases the risk of CIP in cocaine-dependent individuals. COMT genotype and its interaction with early cannabis exposure did not emerge as significant predictors of CIP. In addition, trait vulnerability to CIP may also be familial in nature.

Pharmacogenetic treatments for drug addiction: cocaine, amphetamine and methamphetamine

BACKGROUND

Pharmacogenetics uses genetic variation to predict individual differences in response to medications and holds much promise to improve treatment of addictive disorders.

OBJECTIVES

To review how genetic variation affects responses to cocaine, amphetamine, and methamphetamine and how this information may guide pharmacotherapy.

METHODS

We performed a cross-referenced literature search on pharmacogenetics, cocaine, amphetamine, and methamphetamine.

RESULTS

We describe functional genetic variants for enzymes dopamine-beta-hydroxylase (DbetaH), catechol-O-methyltransferase (COMT), and dopamine transporter (DAT1), dopamine D4 receptor, and brain-derived neurotrophic factor (BDNF). A single nucleotide polymorphism (SNP; C-1021T) in the DbetaH gene is relevant to paranoia associated with disulfiram pharmacotherapy for cocaine addiction. Individuals with variable number tandem repeats (VNTR) of the SLC6A3 gene 3'-untranslated region polymorphism of DAT1 have altered responses to drugs. The 10/10 repeat respond poorly to methylphenidate pharmacotherapy and the 9/9 DAT1 variant show blunted euphoria and physiological response to amphetamine. COMT, D4 receptor, and BDNF polymorphisms are linked to methamphetamine abuse and psychosis.

CONCLUSIONS

Disulfiram and methylphenidate pharmacotherapies for cocaine addiction are optimized by considering polymorphisms affecting DbetaH and DAT1 respectively. Altered subjective effects for amphetamine in DAT1 VNTR variants suggest a 'protected' phenotype.

SCIENTIFIC SIGNIFICANCE

Pharmacogenetic-based treatments for psychostimulant addiction are critical for successful treatment.

Subjective responses and cardiovascular effects of self-administered cocaine in cocaine-abusing men and women

This study aimed to examine sex differences in cocaine self-administration and cocaine-induced subjective and cardiovascular measures. The research was based on secondary analysis of data collected in our human laboratory in which subjects self-administered cocaine infusions (8, 16 and 32 mg/70 kg) over a 2-hour period under a fixed ratio 1, 5 minute time out schedule in three test sessions. Subjects were 10 women and 21 men with a history of either cocaine abuse or dependence who were not currently seeking treatment. Women and men self-administered similar amounts of cocaine. None of the subjective effects measures showed a significant main effect of sex during the cocaine self-administration session. Significant interactions were observed for subjective ratings of 'high' (sex x time) and 'stimulated' (sex x time x dose), with women reporting lower ratings over time/doses than men. Relative to men, cocaine produced dose- and time-dependent increases in feelings of hunger (i.e., reduced appetite suppression) in women. Systolic and diastolic blood pressures showed different patterns of change in men and women, with women showing less robust cocaine-induced increases than men. Taken together, these findings suggest that women and men may differ in their subjective and cardiovascular responses to self-administered cocaine. Further research that prospectively controls for hormonal influences upon these measures is needed.

Presence and persistence of psychotic symptoms in cocaine- versus methamphetamine-dependent participants

The primary objective of this study was to compare and contrast psychotic symptoms reported by cocaine- and methamphetamine-dependent individuals. Participants included 27 cocaine-dependent and 25 methamphetamine-dependent males, as well as 15 cocaine-dependent and 18 methamphetamine-dependent females. After screening, participants were excluded if they met criteria for any Axis I diagnosis other than nicotine dependence, or methamphetamine or cocaine dependence (ie, participants had to use either methamphetamine or cocaine but were excluded if they met dependence criteria for both). The participants were administered the newly developed Psychotic Symptom Assessment Scale (PSAS), which assesses psychotic symptoms. A high proportion of both cocaine- and methamphetamine-dependent men and women reported delusions of paranoia and auditory hallucinations. However, during the abstinent and intoxicated conditions, methamphetamine-dependent men and women were more likely than cocaine-dependent men and women to report psychotic symptoms. Future studies will compare psychotic symptoms reported by non-dependent recreational stimulant users to stimulant-dependent individuals.

Dopamine beta-hydroxylase gene (DbetaH) -1021C-->T influences self-reported paranoia during cocaine self-administration

BACKGROUND

Variation in the gene for dopamine beta-hydroxylase (DbetaH) has been reported to associate with cocaine-induced paranoia as assessed by retrospective self-report. This association has yet to be tested prospectively.

METHODS

Visual analog scale (VAS) ratings of paranoia were obtained in 31 cocaine users during three cocaine self-administration sessions (8, 16, and 32 mg/70 kg). Pharmacogenetic interactions between cocaine and a putative functional polymorphism in DbetaH (-1021C-->T) were assessed.

RESULTS

VAS self-ratings showed significant or trend-level interactions of genotype and time during each session (p = .004, .09 and .003, respectively) with TT homozygotes endorsing greater paranoia over time than either CT or CC individuals. Interactions were significant at all doses in African Americans (n = 19; p = .02, .04 and .05). No other demographic or experimental variable distinguished genotypic groups.

CONCLUSIONS

Results indicate that individuals homozygous for the 'very low-activity' T allele at DbetaH -1021C-->T show an increased propensity to paranoia over time during cocaine self-administration.