Intravenous drug users and hepatitis C treatment there is no evidence showing that the potential for posttreatment HCV reinfection is a sound reason for not offering treatment to PWID. 4.2. Myth 2: Alcohol consumption before and/or during treatment has major implications for the successful treatment of HCV The biological mechanisms by which alcohol might affect HCV treatment outcomes have been researched (34-37). Alcohol consumption has been found to increase the likelihood of histological steatosis and to accelerate hepatic fibrosis and inflammation in patients with HCV infection (38-42). Some studies have found that alcohol consumption raises the HCV viral load (41); however, a meta-analysis of the effect of alcohol consumption on HCV replication failed to show any association between alcohol consumption and HCV viral load (38). Some studies have reported that a history of alcohol consumption has an adverse effect on HCV treatment outcomes by reducing the probability of attaining SVR (43-46). An earlier study had reported a weak dose– response relationship between the quantity of alcohol ever consumed and the likelihood of failing treatment (45). However, other studies have reported that the weak dose–response effect can be reversed by observing a lengthy period of pretreatment abstinence from alcohol consumption (47, 48). Some other studies have found an association between pretreatment alcohol consumption and treatment outcome; however, a univariate analysis performed after adjusting for other factors in these studies failed to establish any such association (41). The effect of alcohol consumption during treatment independent of the effect of a history of alcohol consumption, on treatment efficacy remains unclear. Some studies have shown that alcohol consumption during treatment has a negative impact on the treatment outcome moreover, a dose–response effect has been observed during a univariate analysis performed in 1 study (41). However, some other studies have reported successful treatment outcomes among patients who have continued to consume moderate amounts of alcohol (up to 24 grams per day) during treatment (49, 50). A study in Canada found that participants who had consumed alcohol 6 months prior to treatment were less likely to complete the treatment regimen and were less likely to attain an SVR; however, even in this study, no association could be found between alcohol consumption during treatment and the treatment outcomes (51). Therefore, in studies where alcohol consumption has been associated with a decrease in SVR, it is unclear if the effect was due to alcohol consumption or a reduced adherence to treatment (40, 49). Indeed, in a treatment study in which continuous alcohol consumption was considered an exclusion criteria for receiving treatment, consuming an average of more than 3 alcoholic drink per day within a year prior to treatment was an independent predictor of early treatment discontinuation after adjusting Higgs P et al. 515 for factors of race, illicit substance use, and income; however, alcohol consumption itself was not associated with attaining an SVR (52). Overall, we found that many of the studies on the effect of alcohol on treatment response did not admit heavy drinkers into treatment; therefore, we could only examine the effects of prior alcohol consumption on the treatment outcome (42, 43, 46-48). Among those studies that did investigate alcohol consumption during treatment, the participant numbers were small, and many studies were on interferon monotherapy, which is a relatively ineffective treatment regimen compared to the latest treatment regimens, and most do not account for potential ambiguity in the outcome (41, 45, 51). 4.2.1. Implications Until further studies can establish the direct effect of alcohol consumption on treatment success, while adjusting for adherence to HCV treatment, it seems reasonable to advise patients to decrease their level of alcohol consumption before and during HCV treatment. However, given that some patients have successfully completed treatment without abstaining from alcohol consumption, a patient’s inability to abstain from alcohol consumption before and during therapy should not be seen as an automatic exclusion criterion for receiving HCV treatment. 4.3. Myth 3: Pre-existing mental health problems among PWID lead to HCV treatment being unviable Depression is one of the most common side-effects of HCV treatment (53); a review reported that up to 40% of the people being treated with interferon experience a mild to moderate depression (54). Several studies have investigated the relationship between depression (judging by either a history of depression or a depression score when commencing the treatment) and treatment outcomes. All studies except 1 have observed no significant relationship between depression and treatment adherence (55), treatment completion (55-57), early or end of treatment response (55, 58), or SVR (56). A larger study found that patients with depression were significantly less likely to complete treatment; however, there was no significant difference in SVR (59). One study examined the difference in treatment outcomes between patients with and without schizophrenia and found no difference in the treatment completion or end-of- treatment response, but the patients with schizophrenia were significantly more likely to achieve an SVR (60). Other studies have involved a combined analysis of various psychiatric disorders on the treatment outcomes. One study found no difference in treatment completion among patients with current or past mood or anxiety disorders (61). Two studies found no difference in treatment completion, end-of-treatment response, or SVR among patients with a current or past psychiatric Hepat Mon. 2011;11(7):513-518