There are many different schools of psychotherapy from Freud onwards, which aimed at more fundamental change in the person than the symptom focus of Cognitive Behaviour Therapy. The downside to this is that therapy can last many months, often years. Whilst approaches differ, as in counselling, the therapists-patient relationship is regarded as crucial and there is a greater attempt to understand the links between current problems and symptoms and early childhood factors which might lie behind their problems. Such understanding and insight can bring great relief.
The science base of Psychotherapy is not as strong as Cognitive Behaviour Therapy and in an evidence-based NHS its role in standard NHS treatment has diminished over the years. Also it is not regarded as cost effective compared to CBT or counselling. However, it has a long and distinguished history and there is much general scientific evidence demonstrating the link between childhood upbringing and psychological disorder .
I personally think the argument for the childhood and teenage roots of disorders is compelling (Books) and weave this dimension into my therapy where it is appropriate. Often, say in the case of depression, the immediate issue is to remove the distressing and disabling symptoms (which is more CBT focussed) but later developing an understanding of the emotional and early roots of these problems can be very helpful and produce a more rounded recovery.
As with Counsellors, Psychotherapists should be registered with the British Association for Counselling and Psychotherapy or the United Kingdom Council for Psychotherapists.