This study investigated the cross- and longitudinal associations between cognitive motivation (COM), self-regulation (SR), and depressive symptoms (DS), to the best of our knowledge, for the first time in a clinical sample before and after treatment. Based on corresponding earlier findings on healthy samples, we tested, whether the reported associations also applied to the clinical field, and established a model that allowed to coherently analyze the mechanisms that were assumed to underlie the long-term interdependencies. As in healthy individuals, COM, and SR were positively related to each other, and negatively to DS. Longitudinally we observed DS to decrease, and COM and SR to increase over time. Further, increasing COM was found to partially mediate the negative association between decreasing DS and increasing SR. These findings thus demonstrate that DS determined the characteristics and, thus, the allocation of resources pertaining to COM and SR. They further point to COM as an important co-determining aspect in this resource (re)allocation process. Our findings add substantially to the current knowledge in personality and clinical psychology by showing that although clinical syndromes may temporarily compromise cognitive capacities, deficits are able to replenish and be enhanced by personal characteristics. This could guide future treatment of depression.