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
Since heterogeneity in depressed patients makes treatment decisions difficult and treatment often unsuccessful, we seek to identify certain subtypes of depression. 30 to 40% of depressed patients... Show moreSince heterogeneity in depressed patients makes treatment decisions difficult and treatment often unsuccessful, we seek to identify certain subtypes of depression. 30 to 40% of depressed patients have anger regulation problems; from irritability to anger attacks. What is the significance of anger in depression? Does it signify a subtype of depression? In the NESDA cohort, we compared a large sample of currently depressed patients with irritability to currently depressed patients without irritability. Irritable depressed patients had more symptoms of depression, more often had comorbid anxiety and had more often attempted suicide than non-irritable depressed patients. In a student sample, we investigated the role of the MAOA genotype and found that women with the high expression variant are possibly more vulnerable to anger or aggression during depression. Using acute tryptophan depletion we temporarily lowered serotonin in remitted depressed patients with and without anger regulation problems during their depression. We found no cognitive differences between the two groups, but the experiment did show us that depressed patients with anger regulation problems may be more serotonergically vulnerable. Further research is needed to elucidate best suited treatment strategies for anger regulation problems in depression Show less