Due to similarity and association of depression with negative symptoms of schizophrenia, many doctors prescribe anti-depressants to patients with negative schizophrenic symptoms.
According to meta-analysis published in British Journal of Psychiatry (Efficacy of anti-depressants in treating the negative symptoms of chronic schizophrenia: Meta-analysis by Surendra p. Singh, Vidhi Sinh, Nilamadhab Kar and Kelvin Chan) there is a good reason to believe that above practice has good evidence base.
Above meta-analysis went through 22 randomized placebo controlled clinical trials. It found that there is a statistically significant symptom relief when anti-depressants were co - prescribed with antipsychotics for negative schizophrenic symptoms.
What are the common negative schizophrenic symptoms?
• Social withdrawal
• Lack of speech
• Lack of drive
Above symptoms are the most common symptoms seen in negative schizophrenia. They are very difficult to treat. Co prescribing Antidepressants are found to be effective in treating negative schizophrenia.
Individual antidepressants that are found to be effective in treating negative symptoms
It seems Ritanserin and Trazadone is more effective in treating negative schizophrenic symptoms. Ritanserin > Trazadone > Fluoxetine
Ritanserin is the generic name of Tisterton. Trazadone is generic name of Desyrel. Fluoxetine is the generic of Prozac. Fluoxetine had minimal effects in treating negative schizophrenia.
Limitations of above meta-analysis
• Numbers of trials are relatively small.
• Number of trials are not adequate in interpreting individual anti-depressant effects.
• Three studies with very large effect size shift whole study to that direction
• No RCTs available for tricyclics, venlafaxine, and mono amine oxidase inhibitors.
1. Efficacy of anti-depressants in treating the negative symptoms of chronic schizophrenia: Meta-analysis by Surendra p. Singh, Vidhi Sinh, Nilamadhab Kar and Kelvin Chan