This thesis leads to empirical insights in the relationship between anger and aggression, on the one hand, and psychopathology, on the other hand, using robust study designs and a broad spectrum of... Show moreThis thesis leads to empirical insights in the relationship between anger and aggression, on the one hand, and psychopathology, on the other hand, using robust study designs and a broad spectrum of anger manifestations. It became clear that the occurrence of anger and aggression are common among both psychiatric outpatients, including individuals with depressive-, anxiety-, and bipolar disorders, and psychiatric inpatients, including individuals with psychotic- and personality disorders. Aggressive behaviour regularly leads to a referral to long-stay inpatient care. As supported by this thesis, the costs of aggression within long-stay wards are high. However, despite the increased awareness and efforts to reduce violence in clinical care among healthcare workers and policymakers, aggression incidents remain highly prevalent in psychiatric inpatient facilities. Research suggests diet to be a modifiable factor affecting mood and behaviour. Yet, the promising effects of nutritional supplementation on aggressive incidents found in previous studies were not replicated in psychiatric inpatients. These results strengthen the need for study of additional preventative and treatment options. Furthermore, our results underline the importance of including vulnerable populations, who are often underrepresented in RCTs, to provide evidence-based care for these groups. Show less