In 2014–2016 a total of 596 multi-problem young adults were recruited in Rotterdam, The Netherlands. All participants were male, between 18 and 27 years old (mean age 21.7), and had sufficient knowledge of the Dutch language to understand the study procedure and the questionnaires. This study was part of a larger study in which participants were recruited from two sites. The first site was a municipal agency (Dutch: Jongerenloket) where young adults between the ages of 18 and 27 can apply for social welfare. Every year over 4000 intakes are carried out by so-called youth coaches . During this intake, the level of self-sufficiency of the young adult is assessed on eleven life domains with the validated Self-Sufficiency Matrix—Dutch version (SSM-D) [68–70], based on the American version of the SSM , on a five-point scale with scores ranging from 1 (acute problems) to 5 (completely self-sufficient). Participants were eligible when they adhered to the following definition: (a) a score of 1 or 2 on the domains Income and Daytime Activities, (b) a maximum score of 3 on at least one of the following domains: Addiction, Mental health, Social network, Justice and (c) a minimum score of 3 on the domain Physical health . Eligible young adults were asked to cooperate voluntarily. As a part of a larger study, N = 436 participants were recruited in this way . The second site was multimodal day treatment program New Opportunities (Dutch: De Nieuwe Kans; DNK). Multi-problem young adults also signed up to DNK themselves or were referred to DNK directly by youth care, probation services, mental health services or social organizations. Therefore, additional participants were recruited directly from DNK (N = 160). From the total study sample (N = 596), 99.3% (N = 592) gave informed consent to conduct the register and record research. Of the N = 592, 65.9% (N = 390) was matched to a record in the CPS system.