I read with interest David Kingdon's contribution (letters, 14 January). He is right that the term 'psychopathic disorder' is often used too broadly. However, in my previous correspondence I intended it to be synonymous with anti-social personality disorder, but stuck to the term used by politicians. His conclusions seem to be consistent with some recommendations from the Ashworth inquiry.

But Mr Howlett's arguments (letters, 14 January) are less convincing.

The term 'forensic' defines the patient group and service framework, not therapeutic intervention. Psychotherapy can take different forms but none is a panacea. Each can be effective in different situations for different problems, and offences involving sex and violence may have numerous causes, some of which may be amenable to specific therapy. But it does not follow that the fundamental characteristics of someone who has anti-social personality disorder can be changed by such measures. There is no such convincing evidence.

The American classification system Mr Howlett quotes is well known and respected and the definition is accurate;

unfortunately, the presence of traits that begin in 'childhood or early adolescence and continue into adulthood' is what defines personality characteristics of all kinds, and is part of the WHO definition of normal personality.

It does not follow that therapy will lead to change. But he is right that the best prospects of therapeutic gain in most situations follow interventions at the earliest opportunity.

Nevertheless, the causes of anti-social personality disorder are multi-factorial, and thus interventions need to be complex. Therapy alone does not seem to provide the solutions which, if they exist, may include social, family, economic and psychological measures.

Sustained anti-social behaviour requires a broad understanding and response from society, and it should not merely be abandoned to mental health services.

Dr Hugh Griffiths Medical director/consultant psychiatrist Northumberland Mental Health trust