Attributing the effects of marital rape in research is problematic as it is nearly impossible to find a large enough sample of spouses to study who have experienced sexual violence but have not also been physically assaulted by their spouse. Marital rape can spread sexually transmitted diseases and HIV, adversely affecting a victim's physical and psychological health. In sub-Saharan countries with very high prevalence rates of HIV, such as Lesotho, instances of multiple partnerships and marital rape exacerbate the spread of HIV.