Discussion
anger, psychiatric, alcohol abuse, impulsivity, irritability, violent
ADVERSE EFFECTS, DISORDERS
The current study explored factors associated with attrition from a clinical trial involving pharmacotherapy aimed at treating impulsive individuals with a history of violent offending. Specifically, we investigated whether attrition from the ReINVEST trial could be predicted by demographic and psychosocial factors identified as attrition risk factors from the literature. Our results found that older age, higher levels of social support, higher levels of education, and psychiatric history were all protective factors against attrition at 24 months, whereas less time spent incarcerated in the past 5 years is associated with dropout. We found no association between referral source or treatment allocation on attrition.Our findings that older age is associated with decreased attrition at 24 months are in line with past studies [Our finding that increased social support is protective against attrition is also in line with past research [Adopting a holistic approach when designing RCTs that foster quality in participants' social networks would enhance study retention. For example, employing case management or peer support strategies for those who report low social support at baseline may minimise dropout and enhance successful rehabilitation. Klaehn et al. (2022, p.294) [Our finding that lower levels of education are associated with increased attrition is consistent with other research [We also found that participants who had spent less time incarcerated in the 5 years prior to randomisation had an increased rate of attrition. While this finding contradicts Zanis et al.’s (2009) [Zapryanavo’s (2020) [Our findings also indicate that those with a history of psychiatric conditions requiring treatment, medication, or hospital admission are significantly less likely to drop out. This is contrary to past research suggesting that psychiatric disorders predict the attrition of violent offenders from programmes [Our finding that referral source does not predict attrition is consistent with past studies that also report a null effect regarding referral source [If a relationship between referral source and attrition exists, it is possible the relationship is mediated by other factors. For example, research on why offenders dropout of psychological treatments indicates that younger, less educated men are more likely to remain in treatment if they are court mandated. In contrast, older, better-educated men may be more likely to remain in treatment if they are not court-ordered [Interestingly, we did not see an effect of treatment allocation on attrition. While this finding is consistent with Coccaro [It is possible that the unique nature of ReINVEST as a community-based trial that offered free access to follow-up appointments with research clinicians and a psychiatrist influenced retention, regardless of treatment allocation. It allowed participants, irrespective of their treatment allocation, to receive ongoing professional healthcare attention and support. This could be appealing, given services can be difficult to access and costly outside of the trial setting. Further, regular appointments provided an opportunity for participants to discuss any concerns or adverse effects, and to feel heard and validated. This sense of support may have enhanced motivation to remain in the trial regardless of treatment allocation. It is possible that for control participants regular appointments with clinicians and a psychiatrist reinforced any experienced placebo effect. The positive psychosocial benefits of attention and care offered as part of an effective treatment team may have been perceived as an improvement in their condition. This suggests that providing offenders access to frequent, consistent, high-quality healthcare can support retention in trials. Further, offenders may be more likely to remain committed to the study, regardless of treatment allocation, if offered empathetic communication that ensures they feel observed and cared for.Previous research indicated that Aboriginal status, relationship status, number of dependents, accommodation type, impulsivity, anger, irritability, and alcohol abuse predict offender dropout from research interventions and clinical trials [