Thesis (MA)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This study investigated aggression types and beliefs about aggression among male psychiatric in-patients, using the Aggression Questionnaire (AQ) and the Expagg Questionnaire (Expagg). Two groups were compared: an aggressive group (.0= 40) and a non-aggressive group (n = 44). As expected, the aggressive group displayed significantly higher levels of self-reported aggression, as reflected by their total scores on the AQ and its four subscales (anger, hostility, physical and verbal aggression). The non-aggressive group scored significantly higher on the Expagg than the aggressive group. This indicates a tendency towards expressive beliefs about aggression where aggression is being viewed as an expression of negative feelings and thus as a temporarily loss of control. The relatively lower Expagg scores for the aggressive group shows a tendency towards instrumental beliefs about aggression where aggression is seen as a means to reach a desired goal and thus as an effort to temporarily gain control over the situation. The total scores on the Expagg correlated negatively with self-reported aggression. The implications for prevention and intervention programs are discussed. / AFRIKAANSE OPSOMMING: Die studie het verskillende aggressietipes asook oortuigings aangaande aggressie van manlike psigiatriese binnepasiënte ondersoek, deur gebruik te maak van die Aggression Questionnaire (AQ) en die Expagg Questionnaire (Expagg). Twee groepe is vergelyk: 'n aggressiewe groep (n=40) en 'n nie-aggressiewe groep (n=44). Die aggressiewe groep het, soos verwag, beduidend hoër vlakke van selfgerapporteerde aggressie behaal. Dit blyk uit die betrokke groep se totale tellings op die AQ en sy vier subskale (woede, vyandigheid, fisiese en verbale aggressie). Die nie-aggressiewe groep het beduidend hoër tellings as die aggressiewe groep op die Expagg behaal. Dit dui op 'n neiging tot die huldiging van 'n stel ekspressiewe oortuigings ten opsigte van aggressie by die nie-aggressiewe groep. Aggressie word dus beskou as die uitdrukking van negatiewe gevoelens en dus as 'n tydelike verlies van kontrole. By die aggressiewe groep dui die relatief laer Expagg-tellings op die huldiging van instrumentele oortuigings ten opsigte van aggressie. Aggressie word dus beskou as 'n poging om 'n verlangde doelwit te bereik en word ervaar as 'n poging om tydelike kontrole oor die situasie te verkry. Die Expagg-totaaltellings het negatief gekorreleer met selfgerapporteerde aggressie. Die implikasies vir voorkomende en intervensieprogramme word bespreek.