background The importance of omega- 3 fatty acids for physical health is now well recognised. It is known to have beneficial effects in the prevention and treatment of cardiovascular disease, hypertension and possibly type 2 diabetes (Simopoulos 1999). There is increasing evidence that omega-3 fatty acids may also be important to mental health and psychiatric disorders. The beneficial effects of omega-3 fatty acids have been examined in schizophrenia, mood disorders, attention- deficit hyperactivity disorder, obsessivecompulsive disorder and borderline personality disorders. Few studies examined the effect of supplementation of omega-3 fatty acids on impulsivity among patients with personality disorder but those who did suggest a beneficial effect of supplementation of omega-3 fatty acids on impulsivity (Virkkunen e.a. 1987; Zanarini e.a. 2003).

aim The aim of this study is to further investigate the effect of omega-3 fatty acid dietary supplements on impulsivity in patients with personality disorders. The relevance of this study and other related studies lies in the fact that reduction in impulsivity (and other mental health problems) as a result of omega-3 supplementation would be an important contribution to public health and specifically to the pharmacological treatment of impulsivity in patients with personality disorders. Furthermore, the nutrients are inexpensive, nontoxic and readily available in specific foods (Hibbeln e.a. 2006).

method Seventy patients diagnosed with a personality disorder and impulsivity problems will enter a double-blind randomized controlled trial of omega-3 fatty acids (4 g fish oil) versus placebo.

results Impulsivity as determined by questionnaires and cognitive tasks will be measured at intake, after 1 week and 8 weeks.

conclusion Our hypothesis is that omega-3 fatty acids dietary supplementation will have a significant beneficial effect on impulsivity in patients with a personality disorder compared to placebo. Secondary outcome measures include other psychological symptoms such as anxiety, hostility and physical complaints.