Diagnosis
Range
At least one comorbid disorder
47–97 %
Personality disorder
26–68 %
Affective disorder
18–54 %
Anxiety disorder
3–49 %
Schizophrenic disorder
0–14 %
A very recent study among patients with nonmedical prescription opioid use found rates of psychiatric comorbidity within the ranges of that meta-analysis (27 % affective disorders, 29 % anxiety disorders; Goldner et al. 2013).
How are the differences in comorbidity rates understood? The findings of clinical studies depend much on the sample selection of patients. Settings, reference period, and differences in diagnostic instruments used for clinical assessment are other factors involved (European Monitoring Center for Drugs and Drug Addiction [EMCDDA] 2013). Psychotic patients are less likely to be accepted in drug treatment services than those with personality, affective, or anxiety disorders. Moreover, diagnostic data from mental health services show substance use disorders in schizophrenic patients at a rate of about one-third (review in National Institute for Health and Clinical Excellence [NICE] 2011), mainly alcohol and cannabis abuse. Cannabis has a potential to provoke psychotic disorders; opiates do not have this effect. A review of European studies found among the most common combinations cannabis use and schizophrenia as well as opioid use and personality or behavioural disorders (EMCDDA 2013).
24.3 From Methadone Maintenance to Heroin Maintenance Treatment
Mental disorders may lead to substance use in an attempt to alleviate unpleasant feelings (Phillips and Johnson 2001). Opiates are known for sedative effects; they may be regarded as instrumental for self-medication in emotional distress occurring with affective and anxiety disorders as well as with negative environmental reactions to personality disorders. Opiate use and opioid agonist treatment may mask psychotic proneness (Maremmani et al. 2003) or even prevent the development of schizophrenic psychosis (Khantzian 1997). A possible consequence could be the preference for opioid substitution treatment. In fact, high rates of psychiatric comorbidity have been documented for methadone maintenance treatment (e.g. two-thirds in the study of Ball and Ross 1991). The Dutch national Reitox (Réseau Européen d’Information sur les Drogues et les Toxicomanies) report 2010 found 84 % psychiatric comorbidity among patients in methadone maintenance treatment (EMCDDA 2011).
Addiction services must be prepared to cope with mental disorders. Looking at retention rates and outcome findings, addiction services seem to achieve this competence over time. Earlier studies found a clear relationship between more severe psychiatric symptomatology and lower retention (McLellan et al. 1993), while no such relationship was found in other studies (Ball and Ross 1991). An improvement of psychiatric care in methadone maintenance treatment followed: recent studies found higher retention in comorbid patients as compared to non-comorbid ones (Gelbkopf et al. 2006; Maremmani et al. 2008).
In this context, it is of interest to see whether pharmaceutical diamorphine (heroin) is a helpful medication for maintenance treatment and whether methadone patients continue to use street heroin and other non-prescribed substances during treatment. A new concept for supervised injectable heroin maintenance treatment (HMT) was set up and researched in a Swiss national prospective cohort study 1994–1996 (Uchtenhagen et al. 1999; Rehm et al. 2001). It comprised a comprehensive assessment and care programme. Entry was restricted to otherwise treatment-resistant heroin addicts. Patients presented themselves for supervised injections of individual dosages of pharmaceutical diamorphine, clinics were open daily, and no take-out of injectables is permitted. The concept was designed to avoid overdose risk and misuse. Ensuing randomised controlled trials in Switzerland, The Netherlands, Germany, Spain, Canada, and England compared the outcomes of injectable (in one trial inhalable) heroin and of oral methadone as agonist medications for maintenance treatment. An overall summary of findings was recently published in an EMCDDA monograph (Strang et al. 2012). Based on positive outcomes, new heroin maintenance has become part of the regular treatment system in Switzerland, The Netherlands, Germany, Denmark, and England, with a total capacity of ca. 2,900 slots in 55 clinics.
24.4 Heroin Maintenance and Psychiatric Comorbidity
24.4.1 Psychiatric Disorders at Entry to Heroin Maintenance Treatment
As expected, a high rate of psychiatric disorders can be found in patients entering HMT. Data are available from the Swiss, the German and the Dutch studies.
In the Swiss cohort study, patients had at entry a history of any Axis I disorder in 65.9 % lifetime and 38.8 % during the last 4 weeks. The highest frequencies were found for affective disorders (55.3 % and 27.1 %, respectively) and anxiety disorders (25.9 % and 18.5 %, respectively). At least one Axis II, personality disorder, was found in 57.6 % (66.7 for men, 57.2 % for women). Altogether, 86 % of patients entering HMT had an Axis I or Axis II disorder (Frei and Rehm 2001). This is substantially higher than the rates of psychiatric disorders found on average in opiate dependence according to the review mentioned above of Frei and Rehm (2002; see Table 24.1). These rates of psychiatric comorbidity at entry to HMT were more or less stable up to 2011.
The Dutch trials also found a high rate of psychiatric disorders; 30 % had at least one Axis I disorder at entry (Blanken et al. 2005).
In the German trial, 48.9 % of all patients entering had at least one psychiatric disorder during the last 12 months. The rate of comorbidity did not differ significantly between patients randomised to heroin or methadone prescription (Schaefer et al. 2010).
24.4.2 Outcomes in Heroin Maintenance Treatment for Comorbid Patients
In all five countries (Switzerland, The Netherlands, Germany, Spain, and Canada) the same treatment concept for heroin maintenance was used, and the comparison groups were patients on oral methadone. However, diagnostic instruments, measurements of outcome, and periods of follow-up observation were quite diverse.
Retention in heroin maintenance treatment in general was high after 2 years (44 %; Oviedo-Joekes et al. 2010), 2.5 years (50 %; Rehm et al. 2001), 4 years (56 %; Blanken et al. 2010), and 6 years (40 %; Güttinger et al. 2003).
The Swiss national prospective cohort study found a significant improvement of overall mental health during the first 18 months in treatment, according to medical examination. The decrease of severe depressive disorders, of severe anxiety and delusional disorders, and of highly aggressive behaviour was already observed during the first 12 months (Uchtenhagen et al. 1999). The randomised trial in Geneva used SF-36 for assessment and the score as outcome after 9 months. Mental health scores in patients receiving heroin improved significantly (Perneger et al. 1998).
The Dutch trials tested injectable and inhalable heroin against oral methadone, using for assessment the European version of the Addiction Severity Index (EuropASI) and the Symptom Checklist 90-revised (SCL-90-R) in a follow-up of 12 months (Blanken et al. 2005). Outcome was determined by a dichotomous multi-domain outcome index (including validated indicators of physical health, mental status, and social functioning). Treatment response was lower in comorbid patients (43.8 %) as compared to non-comorbid patients (55.5 %) at 12-month follow-up. However, because the significance threshold was a difference of at least 20 %, this result was considered to be not significant (Blanken et al. 2005).
In the German trial, SCL-90-R and DSM IV diagnosis were used for assessment and a composite score for measuring outcome (at least 20 % improvement in the Opiate Treatment Index [OTI] health scale and/or at least 20 % improvement in the Global Severity Index [GSI], without a deterioration of more than 20 % in the other area of health, and reduction in the use of street heroin with at least 3 of 5 negative urines in the month prior to the end of the trial, and no increase in cocaine use). Two years after entry, 75.25 % of patients with at least one psychiatric disorder were retained in the heroin maintenance programme, whereas non-comorbid patients had a retention rate of 80.72 %; the difference was considered to be not significant. Improvements in physical and mental health were found in 80 % of patients receiving heroin (Haasen et al. 2007; Schaefer et al. 2010).
The Spanish patients were assessed by use of the EuropASI, the OTI, and the outcome by a EuropASI composite score. After 9 months, the psychological status score had improved significantly from 0.5 to 0.3 (March et al. 2006).
The Canadian trial used also the EuropASI as assessment instrument and an ASI score on the psychiatric status as determinant for outcome. Twelve months after entry to treatment, patients receiving heroin showed a reduction in the psychiatric score (Oviedo-Jokes et al. 2008).
24.5 Comparing Outcomes in Methadone Maintenance and Heroin Maintenance Treatments
The Cochrane Collaboration performed a meta-analysis of eight randomised controlled trials comparing heroin and methadone maintenance treatments. It included the early British trial on the traditional heroin-prescribing model and the new randomised trial with injectable heroin, the Randomised Injectable Opiate Treatment Trial (RIOTT) from the UK. Retention in general was found to be significantly superior in heroin maintenance as compared to methadone maintenance. In all six trials featuring supervised heroin prescribing the heroin patients were more likely to meet the criteria for responders, generally reflecting illicit drug use and/or health and crime. Generally the advantages conferred by heroin were statistically significant. The reviewers conclude: “The available evidence suggests an added value of heroin prescribed alongside flexible doses of methadone for long-term, treatment refractory, opioid users, to reach a decrease in the use of illicit substances, involvement in criminal activity and incarceration, a possible reduction in mortality; and an increase in retention in treatment. Due to the higher rate of serious adverse events, heroin prescription should remain a treatment for people who are currently or have in the past failed maintenance treatment, and it should be provided in clinical settings where proper follow-up is ensured” (Ferri et al. 2011).
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