Step 4 provides specialist treatments within NICE guidelines. In comparison to other steps, Step 4 treats a small minority of people. This is usually because the treatments in steps 2 and 3 haven't helped them enough, or because they are at risk of self-neglect or harm, functional impairment or are dealing with more complex conditions, which possibly include other social factors or chronic, multiple diagnoses.

Step 4 is usually made up of a range of highly qualified therapists such as experienced Cognitive Behavioural Therapists and EMDR therapists.

The needs of people receiving Step 4 services are likely to be more complex, so it is probable that people will be receiving a combination of medication and other treatments. Although some treatments may be similar to those in Steps 2 and 3, the treatment is likely to be more intense or for a longer duration.