The Profile and Structure of Psychotic Symptoms associated with Methamphetamine Use

Background: Methamphetamine use can precipitate a transient psychotic state, referred to as methamphetamine-associated psychosis (MAP). It can be challenging to distinguish MAP from schizophrenia (SZ) in clinical settings, as these disorders share a similar psychiatric symptom profile. The overlap between MAP and SZ has led some people to question whether MAP is better conceptualised as a distinct clinical entity, or as a precipitation of SZ. To address these issues, this thesis aimed to examine the profile and underlying structure of psychotic symptoms associated with methamphetamine use. Methods: Four research approaches were adopted. A systematic review (study one) was conducted to canvas the existing literature for specific psychiatric symptoms, and the duration of symptoms, in MAP (k=94; n=7387). Univariate regression (study two) was used to investigate the association between methamphetamine use and psychiatric symptom prevalence in a cohort of people with primary psychosis (n=636). Exploratory factor analysis (study three) was used to investigate the factor structure of psychiatric symptoms among a cross-sectional survey of people who use methamphetamine (n=153). Latent class analysis (LCA) was used to examine profiles of lifetime psychotic symptoms among people currently using methamphetamine (n=554, study four), and the concordance between these profiles and a diagnosis of SZ was assessed. In study five, LCA was used to investigate profiles of current psychiatric symptoms among people with past-month methamphetamine use (n=160), and the alignment of these profiles with diagnoses of MAP and SZ was examined. Results: The systematic review (study one) found that most commonly reported symptoms of MAP were persecutory delusions, auditory and visual hallucinations, hostility, and conceptual disorganisation. One-quarter of people with MAP reported persistent psychotic symptoms (>1 month after drug cessation). Methamphetamine use was associated with a higher prevalence of hallucinations and persecutory delusions among people with SZ (study two). A three-factor model of psychiatric symptoms was identified amongst people who use methamphetamine (study three), including a positive/activation factor and an affective factor (both associated with methamphetamine use), and a negative symptoms factor (associated with depressant drug use, but not methamphetamine use). Follow-up LCA showed that negative symptoms were not observed among people with positive/activation symptoms. LCA revealed three profiles of lifetime psychotic symptoms (study four), and three profiles of current psychiatric symptoms (study five) amongst methamphetamine users. In both LCA models, a class of individuals who experienced persecutory delusions and hallucinations were differentiated from a smaller class who experienced a wider range of symptoms (i.e. non persecutory delusions) and who were more likely to meet criteria for SZ. Conclusions: Persecutory delusions, hallucinations, hostility, and conceptual disorganisation are prominent symptoms of MAP. Negative symptoms do not appear to be a component of MAP, but rather are associated with polysubstance use. Two distinct psychotic syndromes exist among people who use methamphetamine. These empirically-derived syndromes partially aligned with current diagnostic constructs, and are consistent with the need for a MAP diagnostic category separate from SZ. Greater consideration of specific symptoms (e.g., negative symptoms and non-persecutory delusions) may improve diagnostic accuracy by identifying people with a higher risk of SZ

Latent Psychotic Symptom Profiles Amongst People Who Use Methamphetamine: What Do They Tell Us About Existing Diagnostic Categories?

The inability to distinguish clearly between methamphetamine-related psychosis and schizophrenia has led to the suggestion that “methamphetamine psychosis” does not represent a distinct diagnostic entity but rather that the drug has triggered a vulnerability to schizophrenia. We tested this possibility by exploring the latent class structure of psychotic symptoms amongst people who use the drug and examining how these latent symptom profiles correspond to a diagnosis of schizophrenia. Latent class analysis was carried out on the lifetime psychotic symptoms of 554 current methamphetamine users, of whom 40 met the DSM-IV criteria for schizophrenia. Lifetime diagnoses of schizophrenia and individual psychotic symptoms were assessed using the Composite International Diagnostic Interview. The chosen model found 22% of participants had a high propensity to experience a wide range of psychotic symptoms (schizophrenia-like), whereas the majority (56%) more specifically experienced persecutory delusions and hallucinations (paranoid psychosis) and had a lower probability of these symptoms than the schizophrenia-like class. A third class (22%) had a low probability of all symptoms, with the exception of 34% reporting persecutory delusions. Participants in the schizophrenia-like class were more likely to meet diagnostic criteria for schizophrenia (26 vs. 3 and 1% for each of the other classes, p < 0.001) but the diagnosis failed to encompass 74% of this group. These results are consistent with there being a distinction between schizophrenia and methamphetamine-related psychotic symptoms, both in terms of the propensity to experience psychotic symptoms, as well as the symptom profile; however, this distinction may not be captured well by existing diagnostic classifications

The profile of psychiatric symptoms exacerbated by methamphetamine use

Background: Methamphetamine use can produce symptoms almost indistinguishable from schizophrenia. Distinguishing between the two conditions has been hampered by the lack of a validated symptom profile for methamphetamine-induced psychiatric symptoms. We use data from a longitudinal cohort study to examine the profile of psychiatric symptoms that are acutely exacerbated by methamphetamine use. Methods: 164 methamphetamine users, who did not meet DSM-IV criteria for a lifetime primary psychotic disorder, were followed monthly for one year to assess the relationship between days of methamphetamine use and symptom severity on the 24-item Brief Psychiatric Rating Scale. Exacerbation of psychiatric symptoms with methamphetamine use was quantified using random coefficient models. The dimensions of symptom exacerbation were examined using principal axis factoring and a latent profile analysis. Results: Symptoms exacerbated by methamphetamine loaded on three factors: positive psychotic symptoms (suspiciousness, unusual thought content, hallucinations, bizarre behavior); affective symptoms (depression, suicidality, guilt, hostility, somatic concern, self-neglect); and psychomotor symptoms (tension, excitement, distractibility, motor hyperactivity). Methamphetamine use did not significantly increase negative symptoms. Vulnerability to positive psychotic and affective symptom exacerbation was shared by 28% of participants, and this vulnerability aligned with a past year DSM-IV diagnosis of substance-induced psychosis (38% vs. 22%, χ2(df1) = 3.66, p = 0.056). Conclusion: Methamphetamine use produced a symptom profile comprised of positive psychotic and affective symptoms, which aligned with a diagnosis of substance-induced psychosis, with no evidence of a negative syndrome

Does Monitoring Performance Eliminate the Ego-depletion Phenomenon and Influence Perception of Time?

This study evaluated whether monitoring performance against an objective measure eliminated ego depletion and enhanced the accuracy of one’s temporal perception. Two independent variables, depletion level and monitoring status, were manipulated in 83 undergraduates (71% female, median age ¼ 21.2 years), who were then measured for persistence on a series of anagram puzzles (first dependant variable) and subjective time perception estimates (second dependant variable). While depleted participants in the nonmonitoring condition exhibited significantly less persistence than those in the performance-monitoring or low-depleted conditions, no differences in time perception scores were detected among the four groups. It appears monitoring behavior against an objective measure is a robust tool to improve self-control ability in depleted individuals; however, this effect is unrelated to perception of time

The interaction between parental behavior and motivations to drink alcohol in high school students

Background: Alcohol use during adolescence has been predicted by motives to drink or abstain, as well as parental attitudes to youth drinking. As peers can provide access and opportunities to drink, permissiveness of peers' parents toward alcohol is also of importance. Objectives: We examined whether adolescent alcohol use is predicted by motives to drink or abstain, strictness of one's own parents, alcohol permissiveness by peers' parents, and an interaction between these factors. Method: A sample of high school students from the Pacific Northwest (N = 1056; 49% girls; mage = 15.6) completed alcohol use and parenting measures, the Drinking Motives QuestionnaireRevised, and the Motives for Abstaining from Alcohol Questionnaire. A zero-inflated negative binomial regression model examined the combined influence of motives, parent's strictness, and peer's parents' permissiveness on past month use. Results: Parental permissiveness was associated with higher rates of drinking among students with low (but not high) conformity motives and motives to abstain. Higher parental permissiveness was associated with higher rates of drinking among students with low (but not high) coping motives. Conclusions: Our results demonstrate that parental strictness regarding teen alcohol use extends beyond the family unit to influence adolescent drinking in the broader social network. Parents may have a limited capacity to deter drinking through setting rules and expectations for adolescents who are motived to drink to conform but such limit setting maybe particularly helpful for youth with fewer motives to abstain.Reed College provided financial support to this study

COVID-19 pandemic constricts methamphetamine supply in Perth

This study examines the methamphetamine market and prevalence of methamphetamine use in Perth during the COVID-19 pandemic. Data from the Drug Use Monitoring in Australia program indicate that 38 percent (n=55) of Perth police detainees interviewed between April and June 2020 reported recent methamphetamine use—a significantly lower rate than in January–February 2020. Detainees who used methamphetamine did so on a median of five days in the past month—significantly less often than in previous years (median=15) and in January–February 2020 (median=16).Detainees also reported a threefold increase in the price of methamphetamine (from $30 to$100 per point), and significant declines in methamphetamine availability and quality

The Short Barriers Questionnaire (SBQ): Validity, factor structure and correlates in an out-of-treatment sample of people dependent on methamphetamine

Introduction and aims We validate a brief questionnaire to assess barriers to help-seeking for illicit substance use, and explore the factor structure and correlates of scale scores, among people dependent on methamphetamine. Design and methods We administered a modified version of 27 items from the Barriers Questionnaire to 145 adults who had used methamphetamine in the past month and who screened positive for methamphetamine dependence on the Mini International Neuropsychiatric Interview. We used an exploratory factor analysis to identify the scale's dimensions. We examined correlates of the scale scores, their internal consistency, and their concurrent validity against help-seeking intentions on the General Help Seeking Questionnaire (GHSQ). Results A three factor model (χ2 = 308.6 df=168; RMSEA 0.08 [95% CI 0.06-0.09]; comparative fit index = 0.92) identified low perceived need for treatment (9 items), stigma (6 items), and apprehension about treatment (7 items) with Eigenvalues of 5.7, 3.8 and 2.3 respectively. The final 22-item scale had good internal consistency (Cronbach's alpha 0.83) and correlated negatively with help-seeking intentions on the GHSQ (rs = −0.24 p < .001) and positively with the GHSQ item, "I would not seek help from anyone" (rs = 0.38 p < .001). The scale dimensions of low perceived need, stigma, and apprehension had adequate to good internal consistency (Cronbach's alpha of 0.83, 0.79 and 0.69 respectively) but only low perceived need for treatment correlated significantly with the GHSQ scores. Low perceived need was also related to less severe methamphetamine dependence, not having children, and not having received professional help for methamphetamine use. Stigma was associated with specific demographics (being employed, having children), polysubstance use, and having attended sessions with a counselor or psychologist. Apprehension was associated with poor mental health, more severe substance use, being a woman, and having received help from an ambulance. Discussion and conclusions This short version of the Barriers Questionnaire (the Short Barriers Questionnaire; SBQ) is an internally consistent and valid scale for assessing low perceived need for treatment among people who use methamphetamine. Further work is needed to capture and validate other barriers to help-seeking for this population.The research was funded by the Australian Capital Territory (ACT) Health. We thank representatives from the Canberra Alliance for Harm Minimisation and Advocacy for assisting with the questionnaire development and piloting of the questionnaire. We also thank the advisory group for the project, including Helene Delany and James Bint (the Alcohol and Other Drug Policy Unit, ACT Health), Carrie Fowlie and Julie Robert (Alcohol Tobacco and Other Drug Association ACT), Chris Gough (Canberra Alliance for Harm Minimisation and Advocacy), and David McDonald (Social Research & Evaluation Pty Ltd). We particularly thank the Alcohol Tobacco and Other Drugs Association of the ACT (ATODA) for their support throughout the project

Health-related quality of life among people who use methamphetamine

Introduction and Aims We assessed health‐related quality of life amongst people who use methamphetamine, examined how this related to different patterns of methamphetamine use and what other factors were associated with decrements in quality of life in this sample. Design and Methods A cross‐sectional survey of 169 at least monthly methamphetamine users. Health utility scores were derived using the Assessment of Quality of Life – 4D for the past month (0 reflects death and 1 represents full health; the population mean Assessment of Quality of Life score in Australia is 0.81). Dependence on methamphetamine was a score of 4+ on the Severity of Dependence Scale. Other measures included days of methamphetamine use and other substance use in the past month, injecting methamphetamine, demographics, psychiatric symptoms (score of 4+ on the Brief Psychiatric Rating Scale items) and a lifetime DSM‐IV diagnosis of schizophrenia. Results The mean utility score was 0.52 (95% confidence interval 0.48–0.56). Methamphetamine dependence was associated with lower utility (−0.10, P = 0.003) after adjustment for other univariate correlates of utility. Other factors independently associated with lower utility were being a woman (−0.14, P < 0.001), depression (−0.10, P = 0.008), self‐neglect (−0.08, P = 0.035), schizophrenia (−0.17, P = 0.003) and fewer years of schooling (0.02 per year, P = 0.037). Discussion and Conclusions We found poor quality of life in this sample of methamphetamine users relative to the general population, this being associated with both dependence on methamphetamine and other factors, particularly poor mental health. We also found poorer health amongst women.This research was funded by ACT Health. RM is supported by a Curtin Senior Research Fellowship. AV is supported by an Australia Postgraduate Award