The DSM ( Diagnostic and Statistical Manual of Mental Disorders ) lists different categories of disorders. One of these categories is anxiety disorders, An anxiety disorder is a neurosis a clinical term that refers to a class of functional mental disorders involving distress, and wherein there is a disturbance due to a struggle between one’s personality and his or her patterns of behaviour.  

Anxiety disorder differs from occasional anxiety, as anxiety disorders involve more than just temporary worry or fear.

The different types of anxiety disorders

• Generalised anxiety disorder is characterized by chronic anxiety, exaggerated worry, and tension, even when there is little or nothing to provoke it.
• Phobias are a persistent and irrational fear leading to disturbances due to excessive and maladaptive safety-seeking behaviour toward particular situations (e.g., heights) or objects (e.g., spiders). Within this subsection of the DSM IV, there are other disorders considered phobias, including Social Anxiety Disorder characterized by overwhelming anxiety and excessive self-consciousness in social situations, such as a fear of speaking in front of an audience.
• Panic disorder is characterized by unexpected and repeated episodes of intense fear (e.g., fear of death) accompanied by physical symptoms (chest pain, heart palpitations, shortness of breath) in the absence of real danger.
• Obsessive-Compulsive Disorder, or OCD, is characterized by recurrent, persistent unwanted thoughts leading to compulsive “rituals,” common examples of which include hand washing, counting, checking things, or cleaning. 
• Post-Traumatic Stress Disorder, PTSD, can develop after exposure to traumatic events, (violent assaults, accidents…)

There is good evidence that Anxiety disorders are well-treated by hypnotherapy. 

Relaxation techniques are an approach that makes a good starting point for most anxiety disorders, though it is particularly effective at treating panic disorders in conjunction with GAD to reduce physiological arousal. But in the case of phobias and specific fears, exposure hypnotherapy is the primary approach for reducing anxiety via habituation. In some situations of social anxiety, attentional biases like self-awareness will need to be addressed.