Posttraumatic Stress Disorder, Comorbidity

The term comorbidity refers to co-occurring psychological diagnoses. Posttraumatic stress disorder (PTSD) certainly can exist in the absence of any other psychological syndromes. However, it is very common for people meeting diagnostic criteria for PTSD to simultaneously manifest one or more other diagnoses. Where PTSD is accompanied by other diagnoses, their detection is essential in the development of an appropriate treatment plan. Such a plan can either be primarily behavioral health treatment approaches that are evidence-based or based on a theory that is evidence-based if no treatment exists.

According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR), PTSD comorbidity includes co-occurring anxiety in the form of a specific phobia (diagnostic code 300.29), agoraphobia (300.22), or panic disorder with (300.21) or without agoraphobia (300.01). The same designations are used in the Classification of Mental and Behavioural Disorders: Clinical Descriptions and Diagnostic Guidelines (ICD-10), used since 1994 by the World Health Organization (WHO). For example, in ICD-10, the [Page 453]diagnostic code for PTSD is F43.1 Posttraumatic Stress Disorder.

With the exception of the United States and other countries influenced by the United States, ICD is the international standard diagnostic classification for most general epidemiological purposes. The ICD-10 provides international guidelines for the diagnosis of PTSD. This is largely because of the influence of the American Psychiatric Association and partly because of strong ties with the pharmaceutical industry, which has tied many of its products to the DSM nomenclature.

The DSM-IV-TR and ICD −10 criteria for diagnosis of PTSD are similar, but some differences may affect the determination of comorbidity.

According to Bradley Grinage, who reviewed the research literature of the PTSD diagnosis and its management, the most common comorbid disorders include depression, alcohol abuse, and drug abuse. All, therefore, can at times be considered a consequence of the collection of symptoms expressed in the PTSD patient. For example, the ongoing anxiety and intrusion symptoms of PTSD can be so demoralizing that they lead to depression. Similarly, difficulty tolerating these symptoms of PTSD can lead the individual to try to suppress them by abusing alcohol or drugs. For this reason, when depression, alcohol abuse, or drug abuse is the primary diagnosis, it is important for practitioners to also assess for the possible presence of trauma in the background of the client. This is especially true for women, who tend to internalize their trauma in contrast to men who externalize their trauma in the form of aggression toward others and self. The research literature suggests, however, that in some forms of trauma, depression may be a more common consequence than PTSD and may occur in the absence of PTSD. It is also clear that depressive disorder can be a common and independent sequela of exposure to trauma and having a previous depressive disorder is a risk factor for the development of PTSD once exposure to a trauma occurs.

Some have argued that diagnosing a behavioral or mental health patient or client is more an art than a science. One paper notes, as others have, that the topic of psychiatric comorbidity is complex, and the diagnosis depends highly on the culture. In any event, it is helpful to be alert to the likelihood of the presence of comorbidity when a client reports a trauma history. The more extensive that history is, the more likely it is that more than one syndrome will manifest itself.

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