Accurate Diagnosis of Psychosis

(((I am currently studying for a licensure exam & completing an internship.  This blog post is intended as a study exercise.  In it, I review information from a paper on the accurate diagnosis of psychosis.  It is not intended as a substitute for mental health counseling or diagnosis…)))

Key features of schizophrenia and other psychotic disorders are: (1) delusions; (2) hallucinations; (3) disorganized thinking and speech; (4) disorganized behavior, and; (5) negative symptoms such as anhedonia (American Psychiatric Association, 2013).  This accurate diagnosis of psychotic disorders requires a thorough assessment of longitudinal and cross-sectional information. Many of these disorders are associated with time-related criteria that require close longitudinal observation. For example, brief psychotic disorder has a requirement that symptoms occur between one day and one month (American Psychiatric Association, 2013). Additionally, Schizophreniform disorder has a one to six month requirement, while schizophrenia applies to cases in which symptoms are present for at least six months (American Psychiatric Association, 2013). Other considerations confounding the diagnostic process include an array of comorbid diagnoses that must also be ruled out. For example, in order differentiate between schizoaffective disorder and a mood disorder with psychotic features, the temporal relationship between psychosis and mood is important (American Psychiatric Association, 2013). Finally, since substance use and medical diagnoses produce psychotic symptoms, they must also be ruled out (American Psychiatric Association, 2013). What follows are a list of considerations that can aid in the accurate diagnosis of schizophrenia and other psychotic disorders.

Information Required

There are two important considerations when accurately diagnosing psychotic disorders. Firstly, cross-sectional information and longitudinal observations should be thoroughly gathered (Morrison, 2014). Secondly, diagnostic principles can aid in the effective utilization of this information when sorting through differential diagnoses (Morrison, 2014). This section provides an overview of information necessary for the diagnosis of psychotic symptoms.

Cross-Sectional Information

Utility of the MSE.

Morrison, (2013) describes the Mental Status Exam (MSE) as a cross-sectional snapshot of an individual’s mental status at a particular point in time (p119). With this in mind, it is important to note the limitations of a MSE from a diagnostic perspective. Individually, MSE’s provide little temporally relevant data, vital to the accurate diagnosis of psychotic symptoms (Morrison, 2013). Nonetheless, several MSE’s over period of time can indicate the temporal occurrence of various symptoms as it pertains to diagnostic criteria. Additionally, an individual MSE provides “red flags” that indicate potential issues that require further assessment (Morrison, 2013; Robinson 2002). For example, symptoms in an MSE indicative of psychosis include: (1) hallucinations, (2) delusions, (3) disorganized speech (4) bizarre behavior, and (5) negative symptoms (American Psychiatric Association, 2013).   The utility of these symptoms as a “red flag” for psychosis are supported in Morrison’s (2013) “Diagnostic Tree For Psychotic Symptoms”. In this tool, Morrison (2013) excludes normality as a potential consideration by noting that “even the briefest psychoses warrant some sort of diagnosis” (p187).

Collateral information.

Alongside data from a MSE, collateral information such as a client’s medical history and interviews with family members, are also essential (Morrison, 2014). This collateral information provides a background against which to contextualize observations gathered in a MSE. This aids in the development of a differential diagnosis list that will guide the longitudinal observations required for final diagnosis of a psychotic disorder.

Longitudinal Observations

As stated earlier, the cross-sectional information discussed above, provides “red flags” that indicate potential issues in a client’s underlying symptomatology (Morrison, 2014; Robinson, 2002). Longitudinal observations are also vital to the diagnosis of the psychotic disorders since these diagnoses comprise temporally specific diagnostic criteria (American Psychiatric Association, 2013). What follows is a discussion of key considerations relevant to the longitudinal observations required in the diagnosis of psychotic disorders.

Differential Diagnosis.

The information described earlier, is useful in providing an overall impression of key issues present in a client’s underlying symptomatology (Weigel, March 30, 2015). Utilizing these concerns, a therapist can review diagnostic criteria for various diagnoses to produce a list of differential diagnoses (Weigel, March 30, 2015). These differential diagnoses are helpful as a guide in the longitudinal observations required for psychotic symptoms (Morrison, 2014). This differential diagnosis process begins from an inclusive perspective, as therapists consider “all alternative explanations” (Morrison, 2014, p14).

Assessing Negative Symptoms.

Morrison defines negative symptoms as observable functional deficits in individuals with a psychotic disorder (2014). These negative symptoms include: (1) diminished interests, (2) social isolation, (3) lack of motivation, (4) flattened affect, (5) diminished communication and (6) psychomotor activity (American Psychiatric Association, 2013). It is important to monitor negative symptoms on an ongoing basis since psychotic disorders are associated with a higher risk for depression and substance use (Morrison, 2014). Additionally, this information can aid in the assessment of comorbid diagnoses that alter the long-term prognosis of these patients (Morrison, 2014).

Onset & Duration of Symptoms.

Observations regarding the onset and duration of psychotic symptoms are helpful in differentiating between various psychotic disorders.  For example, while schizophrenia develops slowly, schizophreniform psychosis is associated with a rapid onset (Morrison, 2014). Additionally, while schizophrenia tends to emerge in late teens and twenties, psychotic disorders due to a medical condition aren’t associated with an age of onset (American Psychiatric Association, 2013). Finally, the duration of psychotic symptoms is also useful in differentiating between psychotic disorders.   As stated earlier, many psychotic disorders contain temporally specific criteria that aid in their differentiation (American Psychiatric Association, 2013).

Temporal Relationships.

The observation of temporal relationships between psychosis and other factors can also help rule out disorders in a list of differential diagnoses (Morrison, 2014). For example, differentiating between schizoaffective disorder and a mood disorder with psychosis, requires a careful observation of the relationship between psychosis and affective symptoms (Morrison 2014). Additionally, in order to determine if substance use underlies a psychotic episode, the causal relationship between these factors must be determined (Morrison, 2014). This can occur by simply observing if psychotic symptoms occurring independently of exposure to a substance.

Utilizing Information Diagnostically

In addition to gathering the information described above, knowledge of a few key principles and tools can aid in the accurate diagnosis of psychotic disorders. I briefly discuss these principles and tools described next.

The Diagnostic Tree

Morrison, (2014) provides a diagnostic tree for patients with psychotic symptoms that I found very beneficial in clearing much of my confusion (p189). The logic, which underlies the steps in this diagnostic tree, can help sort through observations diagnostically. A thorough review of this tool is beyond the scope of this paper.   Therefore, I will only review the initial steps in this tool to highlight the inherent logic within it.

  1. STEP ONE – Step one of Morrison’s (2014) diagnostic tree first suggests ruling out psychotic symptoms caused by underlying medical diagnoses (p189). This step relates to a diagnostic principle discussed by Morrison (2014), that states: “Physical symptoms and their treatment can produce or worsen mental symptoms” (p16).
  2. STEP TWO – Step two suggests therapists assess for a history of substance use in order to rule this out as an underlying cause of psychosis (Morrison, 2014). This suggestion relates to the fact that a substance induced psychotic disorder can appear cross-sectionally similar to psychosis (American Psychiatric Association, 2013).
  3. STEP THREE – The DSM-5 manual states that many neurocognitive disorders can present with behavioral disturbances that have psychotic features (American Psychiatric Association, 2013). In light of this fact, the diagnostic tree suggests looking out for a history of dementia or delirium and rule out differential diagnoses accordingly (Morrison, 2014).
  4. STEP FOUR – Morrison (2014) states that “somatizing patients report hallucinations or delusions that superficially resemble those of schizophrenia” (p188). The DSM-5 states that differences in the relative strength of these symptoms can help differentiate psychotic disorders from somatizing symptoms (American Psychiatric Association, 2013).   In light of these facts, the diagnostic tree suggests considering somatic symptoms when attempting to rule out disorders in a differential diagnosis list (Morrison, 2013).

Diagnostic Principles  

Other principles can be found in the DSM-5 that can help in utilizing information effectively from a diagnostic perspective.   The DSM-5 states that clinicians should first consider “diagnoses that do not reach full criteria for a psychotic disorder or are limited to on domain of psychopathology” (American Psychiatric Association, 2013, p88). After these diagnoses are ruled out, the DSM-5 then suggests that time-limited conditions be considered next (American Psychiatric Association, 2013). Finally schizophrenia is determined only after all other possibilities have been excluded (American Psychiatric Association, 2013). This insight reflects an early observation of the DSM-5 that much thought has gone into the organization of diagnoses in each chapter.

Assessment Plan for Substance Use & Psychosis

The final question posed for this assignment asks us to consider how we would assess individuals with psychotic symptoms and a substance use history. What follows is an overview of important considerations that can aid in this process.

Understanding The Problem

            Several facts shed light on the importance of assessing for a substance use history in individuals with psychotic symptoms. Firstly, rates of comorbidity for substance use are high in individuals with a diagnosis of schizophrenia (Morrison, 2014). Additionally, substance use is associated with a poorer prognosis for individuals with a psychotic disorder (Rosenthal & Miner, 1997; Schanzer, 2006). Finally, inappropriate treatment regimens are often the consequence of a failure to recognize a substance use issue (Rosenthal & Miner, 1997; Schanzer, 2006). These problems are also frequently exacerbated by the fact that these co-occurring symptoms are difficult to sort through emergently (Schanzer, 2006).   This is especially concerning since 17-37% of individuals with a first-episode of psychosis are found to have symptoms of substance use (Schanzer, 2006).

Developing a Solution

Creating a differential diagnosis list that addresses all presenting concerns can be helpful in addressing the issues discussed above (Morrison, 2014). As stated earlier, many psychotic episodes in patients with a substance use disorder appear cross-sectionally similar to psychotic disorders (American Psychiatric Association, 2013). This fact sheds light on the importance of carefully assessing an individual’s substance use history from the outset. In addition to obtaining a substance use history from the client, collateral data from medical records and family members can aid in the clarification of matters.   Following these clients closely and noting the temporal relationship between psychotic features and substance use aid therapists in determining a final diagnosis (Morrison, 2014; Rosenthal & Miner, 1997; Schanzer, 2006). In the interim, diagnostic uncertainty can be addressed by listing substance use concerns either as a provisional diagnosis, or disorder to rule out (Weigel, March 30, 2015). This can ensure a patient receives the substance abuse treatment they need, while a final diagnose is determined (Weigel, March, 30, 2015).

Understanding Diagnostic Criteria  

One final consideration that can aid in a plan to assess the co-occurring substance use and psychosis symptoms, is a thorough review of all relevant diagnostic criteria.   A review of insights from the DSM-5 pertaining to the assessment of substance use and psychosis is next (American Psychiatric Association, 2013). Overall, longitudinal observations are vital to determining the temporal relationship between substance use and psychosis (Morrison, 2014).

  1. Substance/Medication-Induced Psychotic Disorder (SMIPD): This disorder is indicated when hallucinations and delusions occur upon ingestion of a substance with resolution of symptoms after withdrawal (American Psychiatric Association, 2013). Atypical features, not generally associated with a psychotic disorder can also be supportive this diagnosis (American Psychiatric Association, 2013).
  2. Substance Abuse & Withdrawal: Altered perceptions are commonly associated with substance abuse withdrawal. Nonetheless, this issue is differentiated from SMIPD and psychosis due to the presence of reality testing abilities during the experience of altered perceptions (American Psychiatric Association, 2013).
  3. Dual-Diagnosis (Vern & Ted): Morrison, (2014), provides two case studies that show how a dual diagnosis can be differentiated from either SMIPD or substance withdrawal. In the case study of Vern, there exists a long-term history of schizophrenia that has been well managed. A sudden worsening of psychotic symptoms is observed alongside a known ingestion of substance. In contrast, the case study of Ted shows an individual with a long substance use history alongside a recent diagnosis of schizophrenia. After reviewing these cases, Morrison, (2013), stresses the importance of addressing all symptoms. Dr. Weigel, (April 10, 2015), states that if symptoms are “left over” from one diagnosis and unaddressed then comorbidity is indicated and a dual diagnosis should be considered.


American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.
Morrison, J. (2014). Diagnosis made easier: Principles and techniques for mental health clinicians, 2nd ed. New York: The Guildford Press.
Robinson, D (2002). Mental Status Exam Explained, 2nd ed. Rapid Psychler.
Rosenthal, R. N., & Miner, C. R. (1997). Differential diagnosis of substance-induced psychosis and schizophrenia in patients with substance use disorders. Schizophrenia Bulletin, 23(2), 187-193.
Schanzer, B. M., First, M. B., Dominguez, B., Hasin, D. S., & Caton, C. L. M. (2006).  Diagnosing psychotic disorders in the emergency department in the context of substance use. Psychiatric Services, 57(10), 1468-73. Retrieved from
Weigel, S. (March 30, 2015). First set of cases [Online Forum] Retrieved from:
Weigel, S. (April 10, 2015). Re-using symptoms [Online Forum] Retrieved from:


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