I consider severe cases...DID...suicidal tendencies, self harm, etc.
I've experienced both long term and short term therapy.
My long term therapy lasted 16 years with one therapist. That's not a typo! I had DID when I started seeing the therapist. I was very involved in my therapy, keeping journals and reading anything I could get my hands on about healing from abuse and dealing with DID. In addition I started and ran support groups for survivors of abuse.
At all times the therapist encouraged self-sustainability rather than reliance on him. For instance, an alter had a crisis and needed intervention. I was taught over the phone how to deal with the situation on my own. I'm always grateful that the therapist had taught me self reliance.
I was a high functioning DID. I had a history of sexual abuse and emotional/mental abuse in my FOO. My mother had NPD and OCPD (not obsessive compulsive disorder).
During the long term therapy, I didn't know my father was a psychopath. Of course that added another dimension to therapy. When I stopped seeing that therapist I had integrated the huge internal system I had developed as a child and no longer had DID. All of the integration occurred away from therapy
not during sessions. I was told that rarely happens.
I stopped seeing a therapist for five years.
Then my mother died and a whole new slew of memories surfaced. This is when I figured out that my father was a pedophiliac, serial killer. I entered therapy with a different therapist due to suicidal depression. I stayed with her for only a year because she was ineffectual. Before I left, I gave her a review of her services. She wasn't pleased with hearing what I had to say. I'm certain no one had ever done one in person for her. I've read that it's rare for a client to ever do it. I felt right about doing it, and I didn't care if she denied everything I said. The best thing I did during this therapy was report my father's criminal acts to the police.
I found another therapist and stayed with him for less than 3 years. The thing I learned from him was that grieving didn't have a right or wrong way and would continue for the rest of my life, waxing and waning. I thought grieving had a specific end. It's a journey. I learned that new memories would surface from time to time, and I had a choice what to do with them. When I left therapy I felt I learned the most during my last 3 years. Though the concentration of therapy was different; we focused on my writing assignments and moving forward with my life. They were interesting ones such as writing from my father's point of view. It was done to teach me that I wasn't my father. Or selecting an object in my home which represented my mother. I chose a can of WD-40. I loved writing about that choice. ;)
The second focus of therapy couldn't have happened without the first focus of therapy—integrating alters. I needed both.