Spontaneous recurrence of methampetamine psychosis: increased sensitivity to stress associated with noradrenergic hyperactivity and dopaminergic change

Methamphetamine dependence with and without psychotic symptoms: A multi-modal brain imaging study

OBJECTIVE

Methamphetamine dependence can lead to psychotic symptoms which may be mediated by frontal, striatal, limbic, and thalamic regions. There are few neuroimaging data that allow comparison of individuals with methamphetamine dependence who do, and do not, have psychosis. Two complementary imaging techniques were employed to investigate neurocircuitry associated with methamphetamine dependence with and without psychotic symptoms.

METHODS

Three groups of participants were recruited: methamphetamine dependent (MAA) (N = 11), methamphetamine dependent with psychotic symptoms (MAP) (N = 14), and controls (N = 14). Resting brain glucose metabolism was measured using [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography (PET) and cerebral perfusion was assessed using arterial spin labelling (ASL) magnetic resonance imaging.

RESULTS

Methamphetamine abusers (MAA and MAP groups) had decreased glucose metabolism compared to healthy controls in the left insula, left precentral gyrus, and the anterior cingulate cortex. Compared to MAA participants, MAP participants had 1) decreased glucose metabolism in the left precentral gyrus and the left inferior frontal gyrus and 2) increased glucose metabolism in the putamen and pallidum. MAP participants also had increased cerebral perfusion in the right putamen and right pallidum compared to MAA.

CONCLUSION

Findings support the involvement of frontal, striatal, and limbic regions in methamphetamine dependence. Furthermore, they indicate that glucose metabolism and cerebral perfusion in these regions are disrupted in methamphetamine dependent individuals with psychotic symptoms.

Clinical features, course and treatment of methamphetamine-induced psychosis in psychiatric inpatients

BACKGROUND

Over the past few years, methamphetamine-induced psychosis (MIP) has increased in Iran, accounting for a significant percentage of psychiatry hospital admissions. The present study was conducted with an aim to investigate clinical symptoms, and course and treatment methods of MIP inpatients in Shafa Psychiatry Hospital in northern Iran.

METHODS

Participants were 152 MIP inpatients. Brief Psychiatric Rating Scale (BPRS) subscales of suspiciousness, unusual thought content; hallucinations and hostility were used to measure psychiatric symptoms. Data regarding suicide and homicide and violence were also obtained through interviews with the inpatients and their family. Based on their lengths of recovery time, the inpatients were categorized into 3 clinical groups. These inpatients received their usual treatments and were monitored for their psychiatric symptoms and clinical course of illness. The data were analyzed by descriptive statistics.

RESULTS

The most frequent psychiatric symptoms were violence (75.6 %), intimate partner violence (61.2 %), delusions of persecution (85.5 %), delusions of reference (38.5 %), delusions of grandiosity (32.9 %), delusions of infidelity (30.2 %), auditory hallucinations (51.3 %), visual hallucinations (18.4 %), suicidal thoughts (14.5 %), homicidal thoughts (3.9 %), suicide attempts (10.5 %) and homicide attempts (0.7 %). Recovery from psychotic symptoms in 31.6 % of the inpatients took more than one month. 46.1% of the inpatients were treated with Risperidone and 37.5 % with Olanzapine. Persecutory delusion and auditory hallucination were the most frequent persistent psychotic symptoms. 20.8 % of the inpatients with duration of psychosis more than one month were treated with electroconvulsive therapy (ECT) along with antipsychotics.

CONCLUSION

All forms of violence are highly frequent in MIP inpatients. Our finding agrees with many other studies suggesting that recovery from MIP can take more than a month. Initial promising findings were found regarding the efficacy of Electroconvulsive therapy in MIP patients.

Treatment of methamphetamine-induced psychosis: a double-blind randomized controlled trial comparing haloperidol and quetiapine

RATIONALE

To our knowledge, only a few double-blind randomized controlled trials with antipsychotic drugs have been conducted to examine the treatment of methamphetamine-induced psychosis (MAP).

OBJECTIVES

The aims of this study are to compare the antipsychotic and adverse events of quetiapine, an atypical antipsychotic drug, to haloperidol, a standard treatment for primary psychotic disorder, in individuals with MAP.

METHODS

Eighty individuals with MAP were randomly assigned into two groups, i.e. treatment with quetiapine (n = 36) and haloperidol (n = 44). Sixty-eight patients (85 %) completed the study protocol, i.e. treatment with quetiapine at least 100 mg per day or haloperidol at least 2 mg per day orally once a day for 4 weeks. The doses were increased every 5 days until no psychotic symptom was observed from the Positive and Negative Syndrome Scale (PANSS). Data were analysed by survival analysis with Cox's proportional regression analysis, general estimating equations and log-rank tests.

RESULTS

Thirty-two (89 %) subjects from the quetiapine group and 37 subjects (84 %) from the haloperidol group met the remission criteria at the end of the study. Baseline PANSS total scores of quetiapine and haloperidol groups were 82.4 ± 16.6 and 90.0 ± 18.4, respectively (mean ± SD; p = 0.06). The change-from-baseline scores were -47.8 for the quetiapine group and -53.2 for the haloperidol group. There were no significant differences between the antipsychotic effects (coefficient value = -2.6, p = 0.32, 95%CI = -7.6, 2.5) and the adverse effects of quetiapine and haloperidol.

CONCLUSIONS

Quetiapine may be used as an antipsychotic treatment for MAP with comparable therapeutic effects and adverse events to treatment with classical antipsychotic drugs.

The neurobiology of methamphetamine induced psychosis

Chronic methamphetamine abuse commonly leads to psychosis, with positive and cognitive symptoms that are similar to those of schizophrenia. Methamphetamine induced psychosis (MAP) can persist and diagnoses of MAP often change to a diagnosis of schizophrenia over time. Studies in schizophrenia have found much evidence of cortical GABAergic dysfunction. Methamphetamine psychosis is a well studied model for schizophrenia, however there is little research on the effects of methamphetamine on cortical GABAergic function in the model, and the neurobiology of MAP is unknown. This paper reviews the effects of methamphetamine on dopaminergic pathways, with focus on its ability to increase glutamate release in the cortex. Excess cortical glutamate would likely damage GABAergic interneurons, and evidence of this disturbance as a result of methamphetamine treatment will be discussed. We propose that cortical GABAergic interneurons are particularly vulnerable to glutamate overflow as a result of subcellular location of NMDA receptors on interneurons in the cortex. Damage to cortical GABAergic function would lead to dysregulation of cortical signals, resulting in psychosis, and further support MAP as a model for schizophrenia.

NMDA receptors in the rat VTA: a critical site for social stress to intensify cocaine taking

RATIONALE

Cocaine strengthens behaviors associated with its administration. The stress response by individuals that are defeated in a brief aggressive confrontation can also promote enduring behavioral consequences similar to those of stimulants.

OBJECTIVES

The study intends to find whether intermittent episodes of defeat promote cocaine's reinforcing effects by triggering N-methyl-D: -aspartic acid (NMDA)-receptor-mediated plasticity in the ventral tegmental area (VTA).

MATERIALS AND METHODS

Long-Evans rats were investigated after four social defeats in three experiments. Two experiments examined systemic or intra-VTA antagonism of NMDA receptors during stress on the later expression of behavioral sensitization and cocaine self-administration during fixed and progressive ratio (PR) schedules of reinforcement (0.3 mg/kg/infusion), including a novel 24-h variable-dose continuous access binge (0.2, 0.4, and 0.8 mg/kg/infusion, delivered in an irregular sequence). Third, the expression of receptor proteins NR1 (NMDA) and GluR1 [alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)] were examined in VTA and nucleus accumbens.

RESULTS

Intermittent defeats augment locomotor responses to cocaine and increase cocaine taking. Rates of responding during binges are increased after defeat stress. These effects are prevented when NMDA or AMPA receptor antagonists are administered before defeats. VTA infusions of the NMDA antagonist AP-5 (5 nmol/side) before stress prevents locomotor sensitization to cocaine and intensified responding for cocaine during a PR schedule or binge. Episodic defeats increase GluR1 AMPA subunit protein expression in the VTA.

CONCLUSIONS

Social stress stimulates NMDA receptors in the VTA, and this neural action of defeat may be essential for prompting a later increase in cocaine intake during binges.

Chronic benzylpiperazine (BZP) exposure produces behavioral sensitization and cross-sensitization to methamphetamine (MA)

BACKGROUND

Like other psychostimulant drugs, acute exposure to benzylpiperazine (BZP) increases dopaminergic neurotransmission, producing hyperactivity and stereotypy. The consequences of repeated BZP exposure have not however been investigated. The effects of acute and repeated BZP and methamphetamine (MA) exposure on locomotor activity and stereotypy were measured in order to determine whether there was sensitization and cross-sensitization between these two psychostimulant drugs.

METHODS

The effects of acute treatment with MA (0.0, 0.5, 1.0 and 2.0 mg/kg, intraperitoneal (IP)) or BZP (0.0, 5.0, 10.0, 20.0 and 40.0 mg/kg, IP) on locomotor activity and stereotypy were determined. Effects of repeated exposure were determined in other groups that received five daily injections of 2.0 mg/kg MA, 20.0 mg/kg BZP or vehicle. Following a 2-day withdrawal period, rats from each treatment group received either a low dose MA (0.5 mg/kg) or BZP (10.0 mg/kg).

RESULTS

MA and BZP produced dose-dependent hyperactivity and stereotypy. Repeated MA and BZP resulted in a potentiated locomotor but not stereotypy response. Following the withdrawal period, MA pretreated rats exhibited a sensitized locomotor and stereotypy response to the low dose MA and a conditioned response to saline. BZP pretreated rats also demonstrated a sensitized locomotor response to the low dose of BZP and MA.

CONCLUSIONS

The present findings indicate that repeated exposure to BZP results in sensitization and cross-sensitization to MA.

An association study between catechol-O-methyl transferase gene polymorphism and methamphetamine psychotic disorder

OBJECTIVE

A series of methamphetamine psychosis reveals two kinds of clinical courses of methamphetamine psychosis: transient type and prolonged type. Furthermore, paranoid psychosis sometimes recurs without methamphetamine reuse, referred to as spontaneous relapse. Dysfunction of central dopaminergic neurotransmission has been implicated in the pathogenesis of these psychiatric states. Catechol-O-methyl transferase appears to play a unique role in regulating synaptic dopaminergic activity. This study aimed to investigate whether a functional polymorphism of the catechol-O-methyl transferase gene would be involved in the development of these psychiatric states.

BASIC METHODS

We examined the functional polymorphism of val 158 met (catechol-O-methyl transferase) in 143 patients with methamphetamine psychosis and 200 healthy controls in Japan. The patients were divided into subgroups by several characteristic clinical features.

MAIN RESULTS

We found a significant difference in the catechol-O-methyl transferase allele frequency between patients with spontaneous relapse and the controls (P=0.018, odds ratio=1.67). Odds ratio implied that the patients with spontaneous relapse had a nearly 1.7-fold higher rate of the low activity alleles (met) than the controls.

CONCLUSIONS

Our results indicate that the met allele frequency of the catechol-O-methyl transferase is associated with patients who experienced methamphetamine psychosis and spontaneous relapse, suggesting that patients with a met allele appear to be at increased risk of an adverse response to methamphetamine.

Implications of chronic methamphetamine use: a literature review

Methamphetamine (MA) abuse is increasing to epidemic proportions, both nationally and globally. Chronic MA use has been linked to significant impairments in different arenas of neuropsychological function. To better understand this issue, a computerized literature search (PubMed, 1964-2004) was used to collect research studies examining the neurobiological and neuropsychiatric consequences of chronic MA use. Availability of MA has markedly increased in the United States due to recent technological improvements in both mass production and clandestine synthesis, leading to significant public health, legal, and environmental problems. MA intoxication has been associated with significant psychiatric and medical comorbidity. Research in animal models and human subjects reveals complicated mechanisms of neurotoxicity by which chronic MA use affects catecholamine neurotransmission. This pathology may underlie the characteristic cognitive deficits that plague chronic MA users, who experience impairments in memory and learning, psychomotor speed, and information processing. These impairments have the potential to compromise, in turn, the ability of MA abusers to engage in, and benefit from, psychosocially based chemical-dependency treatment. Development of pharmacological interventions to improve these cognitive impairments in this population may significantly improve the degree to which they may be able to participate in treatment. Atypical antipsychotics may have some promise in this regard.

Neurotoxicity of amphetamine derivatives is mediated by caspase pathway activation in rat cerebellar granule cells

The neurotoxic action of the abuse drugs methamphetamine (METH) and 3,4-methylenedioxymethamphetamine (MDMA) on cerebellar granule neurones (CGNs) culture was examined. Treatment for 48 h with METH or MDMA (1-5 mM) induced a higher decrease in viability than 24 h treatment. z.VAD.fmk (100 microM) but not MK-801 nor NBQX recovered control viability values. In both cases, cell death was characterised as apoptotic rather than necrotic by morphology cell observation. Apoptosis measured by flow cytometry indicated an increase in the hypodiploid population after 48 h treatment with METH and MDMA. Apoptosis was reverted by the presence of z.VAD.fmk (100 microM) but not by 10 microM MK-801 or NBQX. Similar results were obtained by analysing nuclear chromatine condensation. These results ruled out excitotoxic participation in amphetamine derivative-induced neurotoxicity in CGNs. Participation of radical oxygen species (ROS) was evaluated using alpha-tocopherol (1-15 microM) and cytometric studies. The co-treatment with 4 mM METH or MDMA for 48 h partially reverted neurotoxic action and apoptotic features, indicating ROS implication in CGNs death by amphetamine derivatives. Alteration of mitochondrial function induced cytochrome C (Cyt C) release after 48-h treatment with METH and MDMA (4 mM). There was also indication of caspase-3-like activation, measured by immunoanalysis and biochemically. Finally, neurodegenerative action caused by amphetamine derivatives may be prevented by using caspase inhibitors.

Could stress cause psychosis in individuals vulnerable to schizophrenia?

It has long been considered that psychosocial stress plays a role in the expression of symptoms in schizophrenia (SZ), as it interacts with latent neural vulnerability that stems from genetic liability and early environmental insult. Advances in the understanding of the neurobiology of the stress cascade in both animal and human studies lead to a plausible model by which this interaction may occur: through neurotoxic effects on the hippocampus that may involve synaptic remodeling. Of late, the neurodevelopmental model of SZ etiology has been favored. But an elaboration of this schema that credits the impact of postnatal events and considers a role for neurodegenerative changes may be more plausible, given the evidence for gene-environment interaction in SZ expression and progressive structural changes observed with magnetic resonance imaging. Furthermore, new insights into nongliotic neurotoxic effects such as apoptosis, failure of neurogenesis, and changes in circuitry lead to an expansion of the time frame in which environmental effects may mediate expression of SZ symptoms.

Psychotic symptoms in posttraumatic stress disorder

Recent data suggest that the presence of psychotic symptoms in patients suffering from posttraumatic stress disorder (PTSD) may represent an underrecognized and unique subtype of PTSD. Among combat veterans with PTSD, 30% to 40% report auditory or visual hallucinations and/or delusions. The presence of psychotic symptoms in PTSD is associated with a more severe level of psychopathology, similar to that of chronic schizophrenia. In this review, the differential diagnosis of psychotic symptoms in PTSD is discussed, including possible comorbid schizophrenia, psychotic depression, substance-induced psychosis, and personality disorder. A recent biologic study supporting the existence of a unique subtype of PTSD with psychotic features is also addressed, as are the similarities between PTSD with psychotic features and psychotic depression disorder. Finally, data on the treatment implications of psychotic symptoms in PTSD are presented. The intriguing recent findings on psychotic symptoms in PTSD need further investigation in noncombat-related PTSD populations before findings can be generalized to all individuals with PTSD.