Yes, schizophrenia can still be diagnosed even if the patient does not exhibit obvious "first-rank" symptoms. First-rank symptoms, also known as Schneiderian first-rank symptoms, were described by German psychiatrist Kurt Schneider and include specific types of hallucinations, delusions, and thought disorders that were once thought to be highly indicative of schizophrenia.
However, the diagnostic criteria for schizophrenia have evolved over time, and the presence of first-rank symptoms is no longer a strict requirement for making a diagnosis. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the criteria for diagnosing schizophrenia are primarily based on the presence of a combination of positive symptoms (e.g., hallucinations, delusions, disorganized thinking), negative symptoms (e.g., lack of motivation, social withdrawal, reduced emotional expression), and/or cognitive symptoms (e.g., problems with memory, attention, and executive functioning).
The DSM-5 outlines the following diagnostic criteria for schizophrenia:
A. Two or more of the following, each present for a significant portion of time during a one-month period (or less if successfully treated):
- Delusions
- Hallucinations
- Disorganized speech (e.g., frequent derailment or incoherence)
- Grossly disorganized or catatonic behavior
- Negative symptoms (i.e., diminished emotional expression or avolition)
B. Social/occupational dysfunction: For a significant portion of the time since the onset of the disturbance, one or more major areas of functioning, such as work, interpersonal relations, or self-care, are markedly below the level achieved before the onset (or when the onset is in childhood or adolescence, there is a failure to achieve expected level of interpersonal, academic, or occupational functioning).
C. Duration: Continuous signs of the disturbance persist for at least six months. This six-month period must include at least one month of symptoms (or less if successfully treated) that meet Criterion A.
D. Exclusion: Schizoaffective disorder and depressive or bipolar disorder with psychotic features have been ruled out because either (1) no major depressive or manic episodes have occurred concurrently with the active-phase symptoms or (2) if mood episodes have occurred during active-phase symptoms, they have been present for a minority of the total duration of the active and residual periods of the illness.
E. Substance/general medical condition exclusion: The disturbance is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication) or another medical condition.
The diagnosis of schizophrenia requires a thorough evaluation by a qualified mental health professional, who will take into account the patient's history, symptoms, and functional impairment to make an accurate diagnosis. It is essential to consider other potential causes of the patient's symptoms and rule out other medical or psychiatric conditions before arriving at a schizophrenia diagnosis.