Consecutive referrals to a specialist psychotherapy service were analysed for complexity. Some 71% had a severe enduring mental illness or personality disorder. Two-thirds of the rest had added psychosocial or behavioural complexity. Only 9% had no severe enduring mental illness, personality disorder, or added complexity; nearly half of these had somatoform disorder. Only 2% of the patients had uncomplicated depression or anxiety disorders.

Patients treated in this psychotherapy service are substantially different from those on whom NICE bases its guidance for the treatment of depression and anxiety, and for whom IAPT was conceived, it functions as a de facto complex case service.