Psychosocial Interventions in Reducing Cannabis Use in Early Phase Psychosis

Clinical Implications

Motivational interviewing (MI), for patients and families, shows promise for reducing cannabis use in people with early phase psychosis (EPP), and contingency management has preliminary support in people with chronic schizophrenia.

Limitations

Very few RCTs evaluate psychosocial interventions to reduce cannabis use in people with EPP, and results are mixed.

International guidelines for care in EPP recommend not excluding youth and young adults from EISs for psychosis care if they have a comorbid addictions diagnosis. ^9,10 Given the detrimental effects of cannabis on outcomes in EPP, identifying and reducing cannabis use should be a key target for EISs for psychosis. Early intervention services are well positioned to affect negative long-term outcomes due to cannabis use, before use leads to more serious impairment. ¹¹

At present, there is limited research in effective psychosocial interventions to reduce cannabis use in the early psychosis population. Based on our literature review (see Supplemental Tables S1 and S2), ^{12 –33} motivational interviewing (MI) (individual and family) has preliminary support for reducing cannabis use in EPP, with the results for cognitive-behavioural therapy (CBT) being mixed. Psychoeducation, often part of standard care, may improve cannabis use in many people with EPP, making it difficult for an active intervention to demonstrate superiority. CBT and MI had some positive results in chronic populations when cannabis was grouped with other substances, especially when interventions were longer, but gains were not sustained over follow-up periods. Longer interventions for cannabis use in both early and chronic populations were found to be more efficacious in a recent meta-analysis. ³⁴ Contingency management has preliminary evidence in reducing cannabis use in people with severe mental illness ^35,36 but has not been studied in EPP.

In this brief report, we describe the results of a national survey of English-speaking EISs for psychosis to assess current cannabis treatment practices available in the Canadian setting and suggest recommendations to address cannabis use in the EIS for psychosis setting.

Methods

A cross-sectional survey was developed to collect information regarding current cannabis use treatment practices among Canadian English-speaking EISs for psychosis. The survey collected information on the specific treatment modalities (e.g., MI, CBT), formats (individual vs. group), service users (patients vs. families), and substances targeted. The survey also collected information on factors perceived to facilitate service delivery.

Survey questions were dichotomous, contingency based, nominal, ordinal (Likert scale), and short answer. The survey questions were reviewed by the Capital District Health Authority research ethics board and were determined not to require ethics approval.

Surveys were distributed to 35 English-speaking Canadian EISs for psychosis from major urban centres in each province across Canada. Response rates were maximized by 1) sending an introductory email to ask potential respondents to identify the most appropriate clinician for the survey, 2) using collaborators’ names and contact information on all communications to personalize survey implementation, and 3) following up with a telephone call and email if no response was received after 3 months. Based on the clinician’s preference, surveys were emailed, faxed, or administered with an online version of the survey via Dalhousie University Opinio (Opinio version 6.6.2; ObjectPlanet, Inc; Oslo, Norway).

Results

Twenty-seven of 35 (78%) English-speaking EPP clinics across Canada responded to the survey with all provinces with EISs represented. Thirty-seven percent of EISs had formal addiction services and 63% had informal services only, with 15% offering both. Cannabis was targeted specifically in 12% of EISs (those with formal services only). Formal treatment service was defined to be a specific intervention targeting substance use. Figure 1 illustrates frequencies of treatment modalities used in EISs with formal services, and Figure 2 depicts modality frequencies in programs with informal services.

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Figure 1.

Treatment modalities in programs with formal addiction services. CBT, cognitive-behavioural therapy; MI, motivational interviewing.

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Figure 2.

Treatment modalities in programs with informal addiction services. *Other = timeline follow back assessment, multifamily group therapy, concurrent disorders consultation with staff/clients, family support group, recovery group not specific to addictions, and harm reduction.

Individual rather than group therapies were offered more in programs with formal services, with MI, patient and family psychoeducation, and CBT being the most common. Addictions counselors delivered most of the formal addictions services (50%), followed by social workers (40%) and registered nurses (40%), occupational therapists (10%), psychologists (10%), and psychiatrists (10%). Seventy percent of programs with formal treatment services measured outcomes, including stages of change, problems associated with use, quality of life, and symptom scales. Eighty percent of programs with formal services used a screening method to determine treatment eligibility (e.g., clinician assessment, case discussion, or the Alcohol, Smoking, and Substance Involvement Screening Test tool ³⁷ ).

Most of the programs, however, only offered informal services to address cannabis use. While the 4 most common therapies in programs with formal services were offered at rates of 80% to 100%, there was less consistency with informal programs. Individual psychoeducation was the most common (86%), followed by individual MI (76%), group psychoeducation (52%), and informal handouts (52%).

Limitations of formal substance use treatment services generally fell under 3 areas: 1) client-related issues included challenges with engagement and stage of change, 2) staff-related issues included low clinician numbers trained in both substance use and EIS treatment modalities and philosophical differences between addictions and EIS staff (i.e., harm reduction vs. abstinence), and 3) systemic issues involved transportation difficulties for clients and staff, clinic hours, age restrictions, limited access to concurrent disorder services, and lack of crisis management services.

For the majority of programs, the most important factor in the implementation of evidence-based services was training in substance use interventions, followed by having clinicians aware of current evidence-based treatments. Programs with formal services identified that strategies to engage patients were essential to establish their services, while programs without formal services thought administrative support was vital to establish formal services.

Discussion

Informal individual psychoeducation was the most common intervention offered to reduce substance use in Canadian English-speaking EISs, despite preliminary literature that supports the use of MI, with only 12% of programs reporting formal interventions targeting cannabis. There may be regional/program-specific reasons for variations from the evidence-based therapies, including the perception of a lack of consistent or strong signal of effect from long-term studies. However, most EISs identified that training in substance use interventions was the most important factor for implementing services, as well as administrative support, indicating an acknowledgment of lack of training and support in this area rather than concerns of the literature. Of note, contingency management was not used by any respondents, despite some preliminary evidence supporting its use in a chronic population. ^32,35,36 Only a minority of EIS programs offered formal therapies specific to cannabis use, perhaps reflecting the practicality of treating cannabis separate from other substances.

The EPP population may also have low intrinsic motivation to change cannabis use because they perceive that cannabis is a nonharmful, “natural” substance. The Canadian Centre on Substance Abuse reports that Canadian youth considered marijuana to be much healthier and safer than tobacco and less addictive than stimulants and opiates. ³⁸ This suggests the importance of psychoeducation and public health campaigns.

Preliminary studies support family interventions, not only in reducing substance use in patients but also in reducing distress and improving mental health functioning in the family members. ^15,31 However, only a low proportion of surveyed EIS programs use family-based therapies.

EISs with formal addiction services report more group-based interventions than programs with informal services. In a systematic review of psychosocial interventions for people with substance use disorders and severe mental illness, group therapies show a positive impact on substance use outcomes as well as outcomes such as hospitalization, quality of life, and independent living skills. ³⁹ The American Psychiatric Association’s 2006 substance use disorder guidelines support the use of group therapy as they allow efficient use of therapist time and group members who are further along in their recovery to act as positive role models. ⁴⁰

A major strength of this study was our response rate (almost 80%) from every province across Canada with an EIS. To our knowledge, this study is the first to describe substance use treatment services offered in English-speaking Canadian EISs.

Some limitations of our study should be noted. First, the term formal treatment services in our survey was not operationalized. However, respondents seemed to easily be able to self-identify whether they had formal or informal services. Second, despite having a high response rate, we did not contact every EIS across Canada, particularly French-speaking programs, and therefore our results may be less generalizable to French-speaking clinics.

We make the following recommendations for EISs across Canada:

Establish a national task force on addictions treatment in people with EPP with the goals of a) establishing treatment standards that stage treatment based on severity of cannabis abuse, b) establishing standard measures of treatment outcomes and factors predicting treatment response so data can be pooled across Canada, and c) developing training resources for clinicians in the MI, CBT, group, and family interventions that can be shared across Canada.