Triggers and flashbacks
A trigger is a reminder of something traumatic from the past, which can cause you to experience dissociation or other reactions. It could be a sight, sound, taste, smell or touch. It could be a situation or way of moving your body. Many different things can be or become triggers.
In a flashback you may suddenly experience traumatic sensations or feelings from the past. This might be prompted by encountering a trigger. You may experience the flashback as reliving a traumatic event in the present. A flashback may cause you to switch to another part of your identity.