Findings of preserved implicit attention in methamphetamine dependent subjects

Long-term methamphetamine (MA) abuse is associated with a wide range of deficits on explicit tasks of selective attention. Less is known however about the effects of MA abuse on implicit measures of attention. Accordingly, we used a computerized spatial priming task to assess implicit attentional processes in 54 MA dependent subjects (mean age=37.04+/-8.9 years) and 32 healthy controls without history of any form of substance abuse (mean age=33.63+/-7.05 years). The MA dependent subjects had been drug-abstinent a minimum of 3 weeks with a mean duration of MA use of 13.27+/-7.75 years. The MA dependent subjects did not differ significantly from controls on either inhibitory priming [p=.37] or facilitory priming) [p=.69]. This result comports with our earlier findings of intact object-based priming in MA dependent individuals and suggests that intact priming effects extend across spatial domains. Further, this pattern of sparing suggests that cortical brain systems typically supporting implicit attentional functioning are relatively intact in long-term MA dependent individuals whereas brain systems supporting explicit attentional processes are affected.     

Life with jib: A snapshot of street youth's use of crystal methamphetamine

Crystal methamphetamine (CM) is a psychoactive form of methamphetamine whose effects include euphoria, alertness, restlessness, feelings of endless energy, sleep deprivation, depression, paranoia, acute psychosis, and malnutrition. CM use among street-involved youth is high, yet little is known about their patterns of use, the side effects they experience, and the ways in which they manage their drug use and survive on the streets. We undertook a small qualitative study among inner-city, street-involved youth to explore the social context of their CM use. Semi-structured interviews were conducted with twelve youth. Data were analyzed using thematic analysis and four key themes were identified: Patterns of Jib Use, Reasons for Using Jib, Downside of Using, and Managing Jib Use. Each theme revealed interrelationships between drug use and street-involvement. The youth used CM to stay awake to protect belongings, to enhance social interaction, to cope with negative emotions, and as an alternative to psychiatric medications. The negative consequences of CM use included deteriorating physical and mental health, exploitation, isolation, and physical harm. These youth were knowledgeable about their drug use and capable of creatively adapting to many of the related consequences. Social service agencies and health care professionals were not identified as helpful in managing their drug use and its side effects. Although the sample size was small, this data gives insight for policy and program planning aimed at providing treatment and support for street-involved youth using CM.     

Withdrawal symptoms in abstinent methamphetamine‐dependent subjects

Aims Withdrawal symptoms have been linked to a propensity for relapse to drug abuse. Inasmuch as this association applies to methamphetamine (MA) abuse, an understanding of the course of MA withdrawal symptoms may help to direct treatment for MA dependence. Previous studies of symptoms manifested during abstinence from MA have been limited in size and scope. We asked (i) whether debilitating psychological and/or physical symptoms appear during the first several weeks of MA abstinence, (ii) how craving for MA evolves and (iii) whether psychiatric symptoms (e.g. depression, psychosis) persist beyond a month of abstinence. Design A study of MA‐dependent participants, who initiated and maintained abstinence from the drug for up to 5 weeks, compared to a matched healthy comparison group. Setting In‐patient research hospital ward (MA‐dependent subjects) and out‐patient (comparison subjects). Participants Fifty‐six MA‐dependent and eighty‐nine comparison subjects. Measurements Rater‐assessed MA withdrawal questionnaire and self‐report assessment of craving (MA‐dependent subjects) and self‐report assessment of psychiatric symptoms (both groups). Findings At study entry, MA‐dependent subjects exhibited a wide range in severity of depressive symptoms, with the average score at a mild–moderate level of severity. Symptoms of psychosis were also prevalent. While depressive and psychotic symptoms largely resolved within a week of abstinence, craving did not decrease significantly from the time of initiating abstinence until the second week, and then continued at a reduced level to the fifth week. Conclusions Depressive and psychotic symptoms accompany acute withdrawal from methamphetamine but resolve within 1 week. Craving is also present and lasts at least 5 weeks.     

Modulation of the Proteome of Peripheral Blood Mononuclear Cells from HIV-1-Infected Patients by Drugs of Abuse

Introduction  We used proteomic analyses to assess how drug abuse modulates immunologic responses to infections with the human immunodeficiency virus type 1 (HIV-1). Methods  Two-dimensional difference gel electrophoresis was utilized to determine changes in the proteome of peripheral blood mononuclear cells (PBMC) isolated from HIV-1-positive donors that occurred after treatment with cocaine or methamphetamine. Both drugs differentially regulated the expression of several functional classes of proteins. We further isolated specific subpopulations of PBMC to determine which subpopulations were selectively affected by treatment with drugs of abuse. Monocytes, B cells, and T cells were positively or negatively selected from PBMC isolated from HIV-1-positive donors. Results  Our results demonstrate that cocaine and methamphetamine modulate gene expression primarily in monocytes and T cells, the primary targets of HIV-1 infection. Proteomic data were validated with quantitative, real-time polymerase chain reaction. These studies elucidate the molecular mechanisms underlying the effects of drugs of abuse on HIV-1 infections. Several functionally relevant classes of proteins were identified as potential mediators of HIV-1 pathogenesis and disease progression associated with drug abuse.     

Antagonism of footshock stress-induced inhibition of intracranial self-stimulation by naloxone or methamphetamine

Rats were trained to lever-press for intracranial self-stimulation (ICSS) with electrodes implanted in the ventral tegmental area (VTA). The effect of inescapable footshock on response rates to ICSS was examined in the present study. Markedly decreased response rates to ICSS were observed 15 min to 24 h following inescapable footshock. Naloxone (10.0 mg/kg) itself was without effect on response rates to ICSS, but completely antagonized the decreased response rates by the stressor treatment. A relatively low dose of methamphetamine (0.5 mg/kg), which showed no effect on ICSS rates in naive rats, also antagonized the decreased response rates to ICSS. The present results suggest that inescapable footshock may release endorphin in the mesolimbic or mesocortical area; the released endorphin may act on dopaminergic nerve endings and interrupt dopaminergic transmission. The decreased activity of dopaminergic neurons may cause the decreased response rates to ICSS.     

One-year follow-up after multimodal inpatient treatment for cocaine and methamphetamine dependecies

Of a randomly selected sample of 214 patients treated with aversion therapy for cocaine dependence in four chemical dependency units operated by Schick Shadel Hospitals, 156 were followed up 12 to 20 months posttreatment (average 15.2 months). Significant other validation was obtained in 33%. Total abstinence from cocaine for the group overall was 53% at one year post treatment, and current abstinence of at least 6 months at follow-up was 68.6%. Those treating with aversion for cocaine alone had a one-year abstinence of 39% and a current abstinence of 62.4%. Those treating with aversion for alcohol and cocaine had a one-year total abstinence from cocaine of 69% and a current abstinence of 76%. Those treating with aversion for cocaine and marijuana had a one-year total abstinence from cocaine of 50% and a current abstinence of 65%. Those treating with aversion for alcohol, cocaine, and marijuana had a one-year total abstinence from cocaine of 73% and a current abstinence of 73%. One-year total abstinence from alcohol was 54% for those receiving aversion for both alcohol and cocaine and 77% for those receiving aversion for alcohol, cocaine, and marijuana. Current abstinence from alcohol at follow-up was 68% and 81%, respectively. One-year total abstinence from marijuana was 42% for those treating with aversion for cocaine One-year total abstinence from marijuana was 42% for those treating with aversion for cocaine and marijuana and 64% for those treating with aversion for alcohol, cocaine, and marijuana. Current abstinence at follow-up from marijuana was 61% and 81%, respectively. The use of aversion therapy for both alcohol and cocaine in alcoholics who were also using cocaine was associated with higher total abstinence rates (88% vs. 55%) from cocaine when compared with alcoholics who used cocaine but received no aversion as part of their program. The conclusion is tentative since the follow-up rate in this study was lower than that of the previous study (64% vs. 84%). Being around other users accounted for 49% of relapse situations. Family/Work stress was associated with relapse in 33% of cases and unpleasant feelings in 24% of cases. The use of both reinforcement treatments and the use of support following treatment were associated with improved abstinence rates from cocaine. Those patients who reported losing all urges for cocaine after treatment had a total abstinence from cocaine of 90%, those who reported losing all the uncontrollable urges had a total abstinence of 64%, and those who reported still having the urge reported only 33% total abstinence from cocaine.     

The effects of enriched environment on the behavioral and corticosterone response to methamphetamine in adolescent and adult mice

Methamphetamine alters behavior and the stress response system. Relatively little research has examined the effects of methamphetamine in adolescents and compared these effects to those in adults. Housing in enriched environments has been explored as one way to protect against the effects of methamphetamine, but the findings are conflicting and no study has examined how enriched environment may alter the behavioral and corticosterone responses to methamphetamine in adolescent and adult rodents. We examined the long‐term effects of methamphetamine exposure on anxiety, social behavior, behavioral despair, and corticosterone levels in adolescent and adult mice housed in enriched or isolated environments. Enriched environment did not alter the behavioral or corticosterone response to methamphetamine. Methamphetamine exposure decreased anxiety and increased behavioral despair in adult mice, but methamphetamine did not alter behavior in adolescent mice. There was no effect of methamphetamine on social behavior or corticosterone levels. Our findings demonstrate that the specific environmental enrichment paradigm used in this study was not sufficient to mitigate the behavioral effects of methamphetamine and that adolescent mice are relatively resistant to the effects of methamphetamine compared to adult mice.     

Association of methamphetamine use and restrictive interventions in an acute adult inpatient mental health unit: A retrospective cohort study

The aim of the present study was to describe incidences of restrictive interventions and the association of methamphetamine use at an acute adult inpatient mental health unit in metropolitan Melbourne, Victoria, Australia. A total of 232 consecutive consumer admissions to the inpatient unit across a 3‐month period were described for illicit substance use and the use of restrictive interventions (seclusion, mechanical restraint, and physical restraint) prior to and during admission. Of all admissions, 25 (10.8%) involved consumers subjected to a restrictive intervention. Methamphetamine use was either self‐reported or detected by saliva test for 71 (30.6%) consumers. Following multivariate analyses, methamphetamine use (odds ratio (OR): 7.83, 95% confidence interval (CI): 2.33–26.31) and restrictive intervention in the emergency department prior to admission (OR: 8.85, 95% CI: 2.83–27.70) were significant independent predictors of the use of restrictive interventions after inpatient admission. Anecdotal observations provided by clinical mental health staff that consumers intoxicated with methamphetamine appear to require restrictive intervention more frequently than other consumers was confirmed with the results of the current study. As the state of Victoria in Australia is on a pathway to the elimination of the use of restrictive interventions in mental health services, clinicians need to develop management strategies that provide specialist mental health care using the least‐restrictive interventions. Although 26.8% of methamphetamine users were secluded after admission, restrictive interventions should not be the default management strategy for consumers who present with self‐report or positive screen for methamphetamine use.     

Safety,risk, and aggression: Health professionals’ experiences of caring for people affected by methamphetamine when presenting for emergency care

The crystalline form of methamphetamine, commonly known as crystal meth (crystal methamphetamine) or ICE, is a highly‐addictive and powerful stimulant. Users of crystal meth often require emergency care, and are associated with a substantial burden of care by emergency care providers. The aim of the present qualitative study was to explore health professionals’ experiences of providing care for patients affected by ICE who presented to the emergency department (ED). Nine semistructured interviews were conducted. The major theme, ‘staying safe’, was revealed, in which participants described their experiences of being exposed to potentially unsafe situations, and their responses to challenging behaviours, including aggression. The findings highlight the need for ED staff to understand the nature of ICE use and its adverse impact on the mental and physical health of users. Furthermore, it is clear that establishing and maintaining safety in the emergency care setting is of utmost importance, and should be a priority for health‐care managers.