Substance use disorders are increasingly being recognized as chronic diseases, with important treatment implications: not only should a finite course of treatment not be expected to be curative, but outcomes of interest must be relevant to the patient and not limited to reduced substance use. While quality of life is a standard outcome measure among other chronic disease treatment, the substance use disorder treatment field has lagged behind in systematically evaluating it. Sustained contact with the treatment system lasting beyond intensive inpatient treatment appears best to maintain treatment’s benefits long-term, therefore the social environments of patients – the larger contexts of their lives, including but not limited to treatment – must also be addressed.
The overall objective of this thesis was to examine changes in quality of life along with natural treatment progression and explore the relationship of these changes to underresearched social factors in order to inform the clinical approach to patients’ social lives. The specific aims were to identify patterns in poor quality of life at entry to SUD treatment; to examine how quality of life changes along with social network developments through the treatment course; and to validate and confirm the utility of a new quality of life instrument.
This thesis used data from The Norwegian Cohort of Patients in Opioid Maintenance Treatment and Other Drug Treatment study, an observational, prospective study of adults entering substance use disorder treatment in 21 facilities throughout Norway. 548 patients entering treatment enrolled at were administered a battery of questionnaires, such as the EuropASI, HSCL-25, and QOL10, through structured interviewed by trained facility staff. One year later, regardless of treatment progression or drop out, participants answered the same questionnaires through interviews with research staff. 338 were included in the longitudinal analysis.
The majority of the sample entered treatment with extremely impaired quality of life as measured through a single item, along with substance-using social networks, poor mental health, and polysubstance use. Depression was associated with the poorest quality of life among women, while physical inactivity, weight dissatisfaction, and eating alone were the most important factors for men. Opioid maintenance treatment medication was a protective factor for both genders.
After one year, 75% of participants were still receiving treatment, 9% had completed, and 15% amount as at study inclusion reported no network (17.5%). Global and social quality of life measured by the QOL10 improved for the entire sample, although global quality of life remained below population norms. The trend in each of the three treatment status groups, and statistically significant for those still in treatment, was for participants who gained or maintained an abstinent network to report the largest gains in quality of life, and for participants who gained a substance-using network or were socially isolated to report the smallest, or clinically negligible, improvements.
In a validation study of the QOL10, factor analysis revealed the QOL10 to measure two domains described as “global quality of life” and “social quality of life”. The global domain correlated negatively with symptoms of clinical anxiety, depression, and physical inactivity; the social domain was only weakly correlated to anxiety. Both domains had satisfactory internal validity, scores were easily calculated, and the QOL10 as a whole presented minimal administrative and participant burden.
At both treatment initiation and one year later, we found quality of life to correlate with lesser explored factors such as physical inactivity and social isolation. These vulnerabilities, along with mental health, should be evaluated immediately in the clinical setting and addressed through exercise and network interventions. Entering treatment without a social network may be a particular risk factor for both dropping out and failing to experience improved quality of life, and network interventions need to be further developed to explicit help isolated patients. Any contact with the treatment system appears to be beneficial to quality of life, but the combination of remaining in treatment after one year and building or maintaining an abstinent network resulted in the highest quality of life.
Quality of life is not a simple proxy for health or for disease or treatment progression, although undoubtedly influenced by these factors. To fully understand how best to support patients’ quality of life, network building, and treatment retention, and to understand the causal mechanisms in these relationships, repeated measurements and sustained contact with patients are needed.