Predictors of serious criminality such as low autonomic arousal have been rigorously investigated. Other individual differences associated with criminality have, in comparison, been neglected in the scientific literature. Anecdotal evidence from practitioners, extreme cases presented in the media, and limited research on adults and undergraduates has suggested that 'sensational interests' (SI) may be a valuable predictor of criminality (SI are defmed as militaristic or occult interests). The present study is concerned with these interest patterns in normal adolescents. This thesis investigated the effects of sensational interests, intrasexual competition, and psychopathology on delinquency. The research also considered how personality interacted with these variables, and the impact these variables had on friendships and sociometric status. Study 1 employed a cross-sectional design using 645 adolescents. Structural equation modelling explained 43% of the variance in delinquent behaviour using the variables under investigation. The most significant variables were intrasexual competition and personality. SI and psychopathology were less predictive than anticipated. Study 2 considered sociometric status and friendships in 216 adolescents. Neither sociometric status nor number of friends was affected by SI or psychopathology. Of far greater importance were intrasexual competition and peer ratings of shyness. Study 3 was a one year follow-up which replicated the first study. This demonstrated SI varied over a one year period during adolescence and had no predictive value in terms of offending. The best predictors of future offending were intrasexual competition and personality. It is concluded that some previous accounts of SI have underestimated their complexity, with the result that SI have been unjustifiably associated with deviant, criminal behaviour. SI may have a role in criminality but their role is crucially dependent on personality and levels of mating effort. SIs alone should not be regarded'as criminogenic. The scope of the present study is assessed and directions for further research identified.