Answer:
Identity diffusion
Explanation:
According to Erikson, adolescents are going through a crisis that has to do with finding their own identity.
Marcia, specifically, identified 4 types of identity (involving exploration and commitment) that adolescents can go through during this stage:
In the example, Julian has gone through mechanics, photography and Buddhism but nothing has held his interest and he hasn't made a commitment with any of those. It could seem that Julian is in the Moratorium stage (because he's been through many interests) but he actually is not exploring alternatives actively or considered to reach a decision for his future.
Therefore, he's in the identity diffusion stage.