Change in Cognitive Function in Stimulant Users (SToP-S_CogFx)

A Prospective Study to Evaluate the Change in Cognitive Function in Stimulant Users

In Hong Kong, methamphetamine use is common and cocaine use has increased steadily over the past few years. While the use of ketamine decreased from 35.8% in 2015 to 13.9% in 2017, methamphetamine and cocaine have become the most commonly used psychotropic substances and account for more than 50% of drug abuses cases in 2017. Among all stimulants, methamphetamine is most commonly used because it releases three times more dopamine than cocaine and the effects can last from eight to twelve hours, compared to two hours for cocaine. On top of its extreme effects, methamphetamine is relatively inexpensive, making it even more accessible to the young population.

Misuse of methamphetamine has long been associated with profound psychological and cognitive disturbance. In reviewing the cognitive data from reasonably well-matched groups of chronic methamphetamine users and healthy controls, the majority of studies have found that chronic methamphetamine users had lower scores on at least some cognitive tests, although some studies are exceptions with entirely nonsignificant differences. A meta-analysis of 17 cross-sectional studies found that chronic methamphetamine users demonstrated significantly lower cognitive scores than healthy controls. The effects were largest for measures of learning, executive functions, memory, and processing speed, although the majority of cognitive domains significantly differed between the groups.

Concerns has been emerging regarding the methodology of the aforementioned results. In particular, the appropriateness of using healthy controls to examine the cognitive effects of stimulant use has been questioned. Much of the published research has fallen victim to using controls with significant baseline differences from the chronic stimulant users, such as years of education. In addition, none of the studies available provided scatter plots of their cognitive data to evaluate the overlap in performance between chronic stimulant users and healthy controls. In fact, many chronic stimulant users have normal cognitive function when compared with normative data. Therefore, the use of the term 'impairment' or 'deficit' in many studies is not fully justified. Another limitation is that it cannot differentiate cognitive weaknesses that may predate stimulant use from those that result from it. Notably, longitudinal studies have shown that childhood deficits in executive function can predict drug abuse in adolescence, suggesting that at least some of the cognitive weaknesses pre-exist in chronic stimulant user. These and other limitations provoked a conclusion that the evidence for cognitive deficits in chronic stimulant users is weak.

In order to overcome the methodological issues observed in previous cross-sectional studies, we propose to conduct a prospective studies to determine the change in cognitive function among stimulant users over time.

Study Overview

• Status: Completed
• Conditions: Cognitive Dysfunction; Substance Use; Cocaine Use; Methamphetamine Abuse; Stimulant Use
• Intervention / Treatment: Behavioral: Cognitive Assessment

• Study Type: Observational
• Enrollment (Actual): 93

Contacts and Locations

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong, 000000
    • Queen Mary Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

stimulant users who have been taking stimulants regularly

Description

Inclusion Criteria:

• Age: 18 - 65 years old at the time of enrolment
• Able to read and communicate in English and/or Chinese
• Able to give informed consent
• Using stimulants as the primary psychoactive substance of abuse
• "Repeated" and "Active" stimulant users as defined by Structured Clinical Interview for DSM-5 Disorders (SCID-5)

Exclusion Criteria:

• Age <18 years old
• Unable to read English or Chinese
• Unable to give informed consent
• Had been diagnosed with other Substance Use or Related Disorders with severity ≥4 according to DSM-5, or other psychoactive substance dependence syndrome according to International Classification of Disease (ICD-10)
• Currently taking regular prescribed psychiatric medications, including antipsychotics, antidepressants, mood stabilizers, anti-epileptics, benzodiazepines, hypnotics, and anti-cholinergic medications.

• Had been diagnosed with other DSM-5 disorders including:

  • Neurodevelopmental Disorders
  • Schizophrenia Spectrum and Other Psychotic Disorders
  • Bipolar and Related Disorders
  • Depressive Disorders, Anxiety Disorders, and Obsessive-Compulsive and Related Disorders
  • Dissociative Disorders, Somatic Symptoms and Related Disorders
  • Feeding and Eating Disorders
  • Sleep-wake Disorders
  • Neurocognitive Disorders

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Stimulant Users; Stimulant users that fulfill SCID-5 clinician version definition for assessment on stimulant use disorder under DSM-5	Behavioral: Cognitive Assessment; Assessment on cognitive dysfunction using standardised cognitive tests

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Montreal Cognitive Assessment	Measure the change in global cognitive function	12 months
Frontal Assessment Battery	Measure the change in executive function	12 months
Diagnostic and Statistical Manual of mental disorders 5th edition (DSM-5 )severity of stimulant use disorder	To determine different severity of stimulant use	12 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Frequency of stimulant use	12 months

Collaborators and Investigators

• Sponsor: The University of Hong Kong
• Collaborators: Beat Drugs Fund Association

Study record dates

Study Major Dates

• Study Start (Actual): October 21, 2019
• Primary Completion (Actual): May 31, 2023
• Study Completion (Actual): December 31, 2023

Study Registration Dates

• First Submitted: August 16, 2019
• First Submitted That Met QC Criteria: August 19, 2019
• First Posted (Actual): August 20, 2019

Study Record Updates

• Last Update Posted (Actual): May 24, 2024
• Last Update Submitted That Met QC Criteria: May 22, 2024
• Last Verified: May 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Chemically-Induced Disorders; Neurocognitive Disorders; Cognition Disorders; Substance-Related Disorders; Cognitive Dysfunction
• Other Study ID Numbers: BDF180058

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No