It is well established that many common adult psychological difficulties have their origins in childhood and adolescence (Kim-Cohen et al., 2003). It is also known that the causes of psychological difficulties such as anxiety, depression, psychosis and attention deficit hyperactivity disorder include both inherited and environmental factors. For instance, stressful life events such as being victimised by peers or losing a loved one increase the risk of experiencing psychological difficulties. Similarly, molecular genetic studies have identified genetic variants that have a small but significant effect on the likelihood of developing common psychological disorders. Better cognitive ability and planning appear to protect individuals from developing psychological problems. This may be because better cognitive processing enables individuals to ‘cope’ more effectively with genetic and environmental risk by allowing them to employ compensatory strategies. Several recent studies support the view that cognitive ability may protect individuals from developing problems when they have either genetic or environmental risk factors (Kendler et al., 2014; Johnson, 2012; Davidovich et al., in press; Pargas et al., 2008; Riglin et al., 2016). In this study, we aim to examine whether cognitive ability and executive functioning protect individuals against developing psychological problems when they are exposed to environmental or genetic risk.