Severe morbid onychophagia: the classification as self-mutilation and a proposed model of maintenance.

OBJECTIVES: The aim of this review is to make a distinction between a mild and a severe form of onychophagia (nailbiting) that has not been adequately recognised in clinical research. Furthermore, the aim is to emphasise the need for greater understanding of the motivation for such self-injury as occurs in the severe form. The purpose of making the distinction is to evaluate whether a label of self-mutilation can be applied to the severe form. If this is the case, the tension-reduction model of self-mutilation can be proposed as the mechanism which may maintain the behaviour in the face of serious social and physical consequences.

METHOD: Examination was made of the literature relating to onychophagia and to self-mutilation. Treatment studies of onychophagia were examined to evaluate the mechanisms by which the behaviour may be maintained.

RESULTS: Considering the self-mutilative nature of the severe form and the common theme of tension reduction in the literature on onychophagia, application of the tension-reduction model of self-mutilation is warranted.

CONCLUSION: There is a need for empirical research as to the tension-reducing nature of severe onychophagia.