Panic disorder

Panic disorder refers to a condition whereby an individual suffers from unexpected attacks of panic symptoms, including: palpitations, sweating, trembling, shortness of breath, choking feelings, chest pain or discomfort, nausea, dizziness, chills, numbness or tingling, derealisation or depersonalisation, fear of losing control, or fear of dying.^{[APA, 2013, pg. 209]} The severity and frequency of the attacks can vary from person to person, from daily to monthly.^{[APA, 2013, pg. 209]} Panic attacks are known to co-occur with other psychiatric conditions, including psychotic disorders, and, when they do, they are associated with increased symptom severity and poorer treatment response.^{[APA, 2013, pg. 217]} In order to differentiate the diagnosis, the cause of the panic attacks must be considered; for a diagnosis of panic disorder, the panic attacks must be unexpected, if the attacks become associated with another disorder then they are no longer unexpected.^{[APA, 2013, pg. 213]}

References:
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition (DSM-5™). © American Psychiatric Association, 2013.

Buckley PF, Miller BJ, Lehrer DS, Castle DJ. Psychiatric comorbidities and schizophrenia. Schizophr Bull 2009; 35 (2): 383–402.

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Rapp EK, White-Ajmani ML, Antonius D, et al. Schizophrenia comorbid with panic disorder: evidence for distinct cognitive profiles. Psychiatry Res 2012; 197 (3): 206–211.