Latent factor structure of a behavioral economic marijuana
Elizabeth R. Aston
Samantha G. Farris
Received: 15 November 2016 /Accepted: 11 April 2017 /Published online: 16 May 2017
Springer-Verlag Berlin Heidelberg 2017
Rationale Drug demand, or relative value, can be assessed via
analysis of behavioral economic purchase task performance.
Five demand indices are typically obtained from drug pur-
Objectives The goal of this research was to determine whether
metrics of marijuana reinforcement from a marijuana purchase
task (MPT) exhibit a latent factor structure that efficiently
characterizes marijuana demand.
Methods Participants were regular marijuana users (n =99;
37.4% female, 71.5% marijuana use days [5 days/week],
15.2% cannabis dependent) who completed study assess-
ments, including the MPT, during a baseline session.
Principal component analysis was used to examine the latent
structure underlying MPT indices. Concurrent validity was
assessed via examination of relationships between latent fac-
tors and marijuana use, past quit attempts, and marijuana
Results A two-factor solution was confirmed as the best
fitting structure, accounting for 88.5% of the overall variance.
Factor 1 (65.8% variance) reflected BPersistence,^ indicating
sensitivity to escalating marijuana price, which comprised
four MPT indices (elasticity, O
, and breakpoint).
Factor 2 (22.7% variance) reflected BAmplitude,^ indicating
the amount consumed at unrestricted price (intensity).
Persistence factor scores were associated with fewer past mar-
ijuana quit attempts and lower expectancies of negative use
outcomes. Amplitude factor scores were associated with more
frequent use, dependence symptoms, craving severity, and
positive marijuana outcome expectancies.
Conclusions Consistent with research on alcohol and ciga-
rette purchase tasks, the MPT can be characterized with a
latent two-factor structure. Thus, demand for marijuana ap-
pears to encompass distinct dimensions of price sensitivity
and volumetric consumption, with differential relations to oth-
er aspects of marijuana motivation.
Exploratory factor analysis
Behavioral economic demand curves can be used to assess the
relative reinforcing value of addictive substances (Hursh et al.
2005). Relative reinforcing value refers to the behavior-
maintaining or behavior-strengthening properties of a given
substance (Johnson and Bickel 2006) and can be assessed
via administration of a drug purchase task. Substance pur-
chase tasks have been used to quantify demand (Bickel et al.
* Elizabeth R. Aston
Center for Alcohol and Addiction Studies, Brown University School
of Public Health, Providence, RI 02903, USA
Department of Psychiatry and Human Behavior, The Warren Alpert
Medical School of Brown University, Providence, RI 02906, USA
The Miriam Hospital, Centers for Behavioral and Preventative
Medicine, Providence, RI 02906, USA
Butler Hospital, Providence, RI 02906, USA
Peter Boris Centre for Addictions Research, McMaster University/St.
Joseph’s Healthcare Hamilton, Hamilton, ON L8N 3K7, Canada
Homewood Research Institute, Guelph, ON N1E 6K9, Canada
Providence Veterans Affairs Medical Center, Providence, RI 02908,
Psychopharmacology (2017) 234:2421–2429