THE RELATIONSHIP BETWEEN POLY-DRUG USE AND MENTAL DISTRESS OVER TIME

This recent study helps further demonstrates what we have been attempting to elucidate via various blogs in this blogsite. Namely that it is distress that drives the addiction cycle to it’s chronic endpoint.

This study looked at how mental distress increases in poly drug use in a dose response fashion and that a greater number of drugs used resulted in a greater increase in mental distress over time.

“A majority of people seeking treatment for a substance use disorder (SUD) also report clinically significant psychiatric symptoms or have a co-occurring mental health condition. While it is unknown if substance use influences development of these symptoms or vice versa, the two are interconnected as greater psychiatric severity is correlated with higher frequency of drug use and patients reporting poly-drug use tend to have greater depressive and suicidal symptomatology.

Burdzovic Andreas and colleagues conducted a 10-year longitudinal study to investigate changes in mental distress over time and its association with illicit poly-drug use among patients seeking treatment for SUD.

Patients were recruited from residential, outpatient, and opioid substitution therapy (OST) treatment programs from 20 facilities in Oslo, Norway.  Participants were eligible if they were admitted for treatment due to illicit drug use. Patients were initially interviewed within two weeks of treatment initiation (n = 481), and again 1 year (n = 428), 2 years (n = 410), 7 years (n = 348), and 10 years (n = 296) after enrolling in the study.

Mental distress (anxiety and depression) in the past 7 days was measured with the Hopkins Symptom Checklist. Scores were averaged to obtain Global Severity Index (GSI) scores ranging from 0 to 4 with higher scores indicating greater mental distress. The authors used the Addiction Severity Index, European version to collect information on substance use during the 30 days prior to each study visit. The four most commonly used illicit substances—heroin, cannabis, sedatives/hypnotics, and amphetamines—were quantified such that a score of 0 indicated use of none of the four drugs in the past month and a score of 4 indicated use of all four drugs in the past month.

At baseline, participants were 68% male and 30.7 years on average. Eighty-two percent had a history of injection drug use, 61% had at least one episode of depression in the past, and 59% had previously experienced an overdose. Over two thirds had used more than one drug in the past month with an average of 2 drugs used. Sixty-two percent used heroin, 59% used cannabis, 51% used sedatives/hypnotics, and 34% used amphetamines. Average GSI was 1.18.

Using multilevel statistical models with poly-drug use as a predictor, and controlling for age and gender, to try to better estimate a unique effect of poly-drug use on psychiatric distress, the authors found that all drug use conditions (i.e., using 1, 2, 3 or 4 drugs) were associated with greater mental distress (i.e., higher GSI score) in a dose-response fashion as GSI estimates increased with increasing number of drugs used.

Next, the authors tested whether the relationship between poly-drug use and psychiatric distress was consistent or whether it changed over the course of the 10 year follow-up period. Results showed that drug use was associated with changes in mental distress over time. Specifically, using 2, 3, or 4 drugs resulted in significantly increased mental distress over time in comparison to using no drugs such that a greater number of drugs used resulted in a greater increase in mental distress over time. Additionally, the mental distress trajectory for those not using drugs declined significantly over time and mental distress trajectory of participants’ using 1 drug was unchanged over time. The graph below depicts the mental health trajectories by drug use category for the 10-year period.