SUD patients with a history of CAN present significant challenges to clinicians and the consequences of CAN have been related to poorer outcomes, lower treatment engagement and retention in this group (Bartholomew, Courtney, Rowan-Szal, & Simpson, 2005; Greenfield et al., 2002). With regard to specialized therapies for SUD patients with comorbidities related to CAN, preference is given to integrated treatments that conceptualize both disorders as related and plan treatment accordingly. While it is unclear if integrated treatments have a superior efficacy compared to one efficacious treatment alone (Torchalla, Nosen, Rostam, & Allen, 2012), the clinical needs of patients with SUD and PTSD often make such an integrated approach necessary. The most studied integrated treatment thus far is ‘Seeking Safety’ (SS; Najavits, 2002). This present-focused programme covers 25 topics that address the diverse consequences of CAN in four domains (cognitive, behavioural, interpersonal and case management) and has been shown to be effective in many SUD samples in the USA. The literature indicates, overall, positive outcomes on SUD and PTSD symptoms, as well as other consequences of CAN, in various populations (Najavits & Hien, 2013). A pilot study in Germany yielded positive results (Kaiser et al., 2015), suggesting that the programme could be a promising option also for European SUD settings, but no controlled studies on the efficacy of this treatment have been published in Europe so far.