PTSD as a Risk Factor Predicting Polydrug Use: A Dual Systems of Self-Control Mediation Model

• DOI: 10.1177/0022042620958198
• Author: Thomas Wojciechowski
• Published date: 01 January 2021
• Date: 01 January 2021
• Subject Matter: Articles

https://doi.org/10.1177/0022042620958198

Journal of Drug Issues

2021, Vol. 51(1) 68 –83

© The Author(s) 2020

Article reuse guidelines:

sagepub.com/journals-permissions

DOI: 10.1177/0022042620958198

journals.sagepub.com/home/jod

Article

PTSD as a Risk Factor Predicting

Polydrug Use: A Dual Systems of

Self-Control Mediation Model

Thomas Wojciechowski1

Abstract

Post-traumatic stress disorder (PTSD) is associated with increased risk for polydrug use. Low

self-control is a key characteristic of the disorder and is predictive of polydrug use. However,

there is a dearth of research focused on the relevance of a dual systems model delineation of

self-control into the constructs of risk-seeking and impulsivity as it pertains to polydrug use

and PTSD. This study tested dual systems mediation of this relationship. Generalized structural

equation modeling was used to test for mediation effects. Results indicated that more PTSD

symptoms predicted increased drug use variety (coefficient = 0.024; confidence interval [CI]

= [0.001, 0.046]). Inclusion of dual systems constructs fully attenuated this relationship. The

total indirect effect achieved marginal significance (coefficient = 0.005; CI = [>−0.001, 0.009]).

Sensitivity analyses of the specific indirect effect of impulsivity as the sole mediator indicated

significant mediation. These results provide some indication that impulsivity-based programming

may help to treat polydrug use among those with severe PTSD.

Keywords

PTSD, dual systems model, self-control, polydrug use

Introduction

Post-traumatic stress disorder (PTSD) is a pervasive mental illness. Specifically, individuals

must present one or more symptoms in each of the following clusters for diagnosis: trauma expo-

sure, intrusion symptoms, avoidance, negative alterations in cognition or mood, and marked

alterations in arousal and reactivity, with all of these lasting more than 1 month. Trauma is defined

as any exposure to actual or threatened death, serious injury, or sexual violence (see the Diagnostic

and Statistical Manual of Mental Disorders [5th ed.; DSM-V]; American Psychiatric Association

[APA], 2013).

The PTSD is associated with increased risk for a range of substance use outcomes (Dworkin

et al., 2018; Wojciechowski, 2018; Yarnell, 2015). Polydrug use is the use of multiple different

types of drugs and PTSD is associated with increased risk for this outcome as well (Alvarez-

Alonso et al., 2016; Mills et al., 2005). Considering that different substances are associated with

increased risk for different health outcomes (Al-Imam, 2017; Ames et al., 2020; Darke et al.,

1Michigan State University, East Lansing, USA

Corresponding Author:

Thomas Wojciechowski, School of Criminal Justice, Michigan State University, 655 Auditorium Road, East Lansing,

MI 48824, USA.

Email: wojcie42@msu.edu

958198JODXXX10.1177/0022042620958198Journal of Drug IssuesWojciechowski

research-article2020

Wojciechowski 69

2016), one could stand to reason that using multiple types of drugs in a given time span would

place individuals at greater risk for a variety of health consequences. Furthermore, estimates

indicate that prevalence rates of polydrug use may be as high as between 18% and 33% (depend-

ing on the country and population of interest) among substance users (Collins et al., 1998; Font-

Mayolas et al., 2013; Karjalainen et al., 2017). Beyond just using multiple drugs, an estimate in

the United States indicated that 1.1% of a large population-based sample reported either polydrug

dependence or abusing multiple drugs, indicating problematic clinical psychopathology associ-

ated with the behavior (Agrawal et al., 2007). The scope of this issue indicates the need for fur-

ther study and examination of PTSD as a predictor, as well as mechanisms underlying this

relationship.

One additional construct that is associated with both PTSD and polydrug use is self-control,

as self-control is diminished among victims of trauma and low self-control is associated with

increased risk for polydrug use (Simmen-Janevska et al., 2015; Vaughn et al., 2009; Wojciechowski,

2019). Although these relationships are well established in the extant literature, more recent

research has provided a more nuanced understanding of self-control as a bidimensional con-

struct. The dual systems model conceptualizes self-control as being comprised of dimensions of

risk-seeking and impulsivity. Risk-seeking refers to the desire to seek out thrilling and novel

experiences, whereas impulsivity refers to the capacity (or lack thereof) to control one’s behavior

and choices when presented with provocative stimuli (Steinberg, 2010). In essence, risk-seeking

represents the fast car that adolescents find themselves driving and impulsivity refers to the

degree to which they have functioning brakes and a steering wheel for said vehicle. Empirical

research has indicated validity for the existence of such a dual systems model (Harden & Tucker-

Drob, 2011; Shulman et al., 2016). Research has provided indication that each construct may

exert independent effects on behavior (Burt et al., 2014; Forrest et al., 2019). Despite this, there

is a dearth of research focused on the relevance of the dual systems model of self-control for

understanding the PTSD–polydrug use relationship. This is problematic, as one or the other self-

control dimension may be a better mediator of this relationship. If this is the case, then program-

ming focused on reducing drug use issues among PTSD-sufferers may be more effective if they

directly target that construct over the other.

Relevance of the Dual Systems Model for PTSD and Polydrug Use

As mentioned above, PTSD-sufferers generally demonstrate increased risk for polydrug use

(Alvarez-Alonso et al., 2016; Mills et al., 2005). Self-control may help to explain this relation-

ship, but past research has been narrow in its understanding of the concept, focusing mainly on

impulsivity, rather than a more holistic conceptualization of self-control. As impulsivity is symp-

tomatic of the disorder, it would seem that this construct may be a particularly salient mediator

of the PTSD–polydrug use relationship because of research indicating that impulsivity is a risk

factor for drug use (Hentges et al., 2018; Kozak et al., 2019; Oshri et al., 2018). Indeed, past

research has found impulsivity helps to explain the PTSD–substance use relationship (Mahoney

et al., 2020; Morris et al., 2020). However, there is a dearth of research that has sought to delin-

eate self-control into the dual systems concepts. This ignores the potential bidimensional nature

of self-control that may further help to clarify this relationship.

While the role of impulsivity as a potential mediator seems clear, the role of risk-seeking may

be a bit more complex. Less research has focused on the role that risk-seeking may play in this

relationship and the extant literature presents a potentially mixed perspective. Hyperarousal is

characteristic of PTSD, which may involve engagement in reckless or self-destructive behavior.

As such, individuals suffering from PTSD may actually present greater risk-seeking behavior.

Some research does indeed indicate that counterphobic risk-seeking and post-traumatic risk-

seeking may be displayed by PTSD-sufferers (James et al., 2014; Kerig, 2019). Although reasons