Positive and Negative Symptoms in Schizophrenia
Direct Answer
Positive symptoms include hallucinations, delusions, and disorganized thought/speech, while negative symptoms encompass flat affect, avolition (lack of motivation), anhedonia (inability to experience pleasure), asociality (social withdrawal), alogia (poverty of speech), and anergy (lack of energy). 1, 2
Positive Symptoms: Symptoms Present in Excess
Positive symptoms represent features that are "added" or present in excess compared to individuals without schizophrenia:
- Hallucinations (most commonly auditory voices that comment on behavior or converse with each other) 2, 3
- Delusions (fixed false beliefs) 1, 4
- Disorganized speech/thought disorder (loose associations, illogical thinking, impaired discourse skills) 1, 5
- Bizarre or disorganized behavior 2, 4
These florid symptoms are typically obvious during acute phases and increase linearly with age in early-onset cases. 1
Negative Symptoms: Symptoms of Deficit
Negative symptoms represent deficits or absence of normal functions:
- Flat/blunted affect (reduced emotional expression) 1, 2, 6
- Avolition/apathy (decreased motivation and goal-directed activity) 2, 6, 4
- Anhedonia (inability to experience pleasure) 2, 6
- Asociality (social withdrawal) 2, 4
- Alogia (poverty of speech and thought content) 1, 2
- Anergy (lack of energy) 1
These symptoms persist in 35-70% of patients after acute episodes resolve and are associated with significantly poorer functional outcomes. 2
The Third Dimension: Disorganized Symptoms
Recent research identifies disorganized behavior as an independent third symptom cluster, distinct from positive and negative symptoms:
- Disorganized speech (thought disorder with loose associations and illogical thinking) 1, 5
- Bizarre behavior 1
- Poor attention and cognitive dysfunction 1, 2
This cluster reflects primarily a disorganization of thought independent of the traditional positive/negative construct. 7
Critical Clinical Distinctions
Developmental Considerations
When assessing children and adolescents, you must differentiate true thought disorder from developmental delays or language disorders, as developmental differences in language and cognition affect symptom presentation quality. 1, 5
Primary vs. Secondary Negative Symptoms
Primary negative symptoms are intrinsic to schizophrenia and persist over time, while secondary negative symptoms result from unrelieved positive symptoms, medication side effects, or depression and may be reversible. 2, 6 This distinction is critical because antipsychotic monotherapy has limited efficacy on primary negative symptoms. 2
Common Diagnostic Pitfalls
- Negative symptoms are subtler and more difficult to recognize than florid positive symptoms, leading to underdiagnosis. 2, 6
- Patients lack insight into the extent and impact of their negative symptoms, and clinicians often prioritize positive symptoms. 2
- Cultural or religious beliefs may be misinterpreted as psychotic symptoms. 2
- Auditory hallucinations alone do not necessarily indicate a psychotic disorder and may result from PTSD, borderline personality disorder, hearing loss, or other causes. 8