*4.3. Collaborative Approaches within the Contingency Contract Process*

One of the aims of the current study was to identify approaches to incorporate patients into the contingency contract process in order to motivate them and enhance compliance and autonomy. In concrete terms, patients (and parents for younger patients) can for example co-determine weight goals, choose consequences and write down the contingency contract in their own words. We found that about 30% of experts let their patients choose consequences or negotiate consequences with the patient and almost half of the experts negotiate weight goals with their patients. This seems promising especially considering that patients are often ambivalent to restore weight [25]. However,

letting patients co-determine weight goals can bare the risk of setting weight goals that are too small. Additionally, negotiating weight goals and weight contingencies with the patient instead of setting them oneself can be a wearisome task for the therapist.

In the literature covering the topic of collaboration in the field of AN, there is a clear preference for collaborative approaches by patients as well as therapists [26]. Furthermore, Williams and Reid [25] showed in their qualitative study that patients with AN feel low self-efficacy about changing behaviors. On one side, AN gives them a sense of control, but the disorder also causes strong feelings of loss of control. The authors conclude that this ambivalence patients experience should be targeted in a collaborative manner [25]. In line with this evidence and the systematic review, which shows an overall movement from the utilization of (directive) contingency management towards more collaborative contingency contracts [18], contingency contracts in Germany should intensify their focus on collaboration within the weight contract process.

## *4.4. Implications for Clinical Practice*

Motivational aspects are one of the main considerations for the improvement of treatment and care for patients with AN [27] and are taken into consideration for example by integrating motivation-based therapeutic styles into treatment [28,29]. Motivation of patients has been shown to play an essential role concerning dropout rates and treatment compliance [30]. Furthermore, internal motivation to change was identified as one of the positive predictors of clinically significant changes in eating disorder psychopathology in patients with AN quantitatively [12] as well as qualitatively in patients' reports [31]. It is therefore worth considering a shift in the treatment approach, from motivating the patients externally through a contingency contract, to enhancing internal motivation for example by incorporating a motivations-based treatment style. Indeed, some of the authors are currently developing a motivation-based intervention, incorporating motivational aspects into the inpatient treatment of patients with AN, which they plan to soon test against existing treatment options.
