Negative symptoms of schizophrenia—such as social withdrawal, avolition, avoidance, lack of spontaneity, anhedonia, poverty of speech, and blunted affect—often persist after successful treatment of positive symptoms, such as hallucinations and delusions.1 Negative symptoms can be debilitating and are associated with poor social and occupational outcomes, as well as cognitive dysfunction. Currently, treatments for negative symptoms are not nearly as effective as treatments for positive symptoms. The mnemonic COMBS can be used to easily recall 3 treatment modalities often used to address negative symptoms.
COgnitive-behavioral therapy
Cognitive-behavioral therapy (CBT) and other psychosocial therapies derived from it, such as social skills training, recovery-oriented cognitive therapy, motivation and enhancement therapy, and cognitive-behavioral social skills training (CBSST), have shown to be effective for treating negative symptoms.2 In a study of 149 patients with schizophrenia, CBSST reduced symptoms of avolition and apathy and improved functioning outcomes.2
Medications
Antipsychotics. Although second-generation antipsychotics (SGAs) were initially promising, accumulating clinical experience and research have shown that these agents have limited efficacy for treating negative symptoms.1 Unlike first-generation antipsychotics, SGAs do not cause affective blunting, and are effective at treating depressive symptoms; however, depressive symptoms can sometimes be difficult to distinguish from negative symptoms. Improvement of depressive symptoms observed with SGA treatment could be mistakenly interpreted as alleviation of negative symptoms; however, clinical trials that focused specifically on treating negative symptoms have found no specific efficacy of SGAs.1
Antidepressants. Although clinical trials and meta-analyses have had mixed results,1 antidepressants appear to be safe add-on treatments with small efficacy for negative symptoms.
Anticonvulsants have long been used as augmentation to antipsychotics for patients with treatment-resistant schizophrenia; however, there is no evidence that these medications can improve negative symptoms.1
Stimulants. There is no strong evidence that stimulants could be an efficacious treatment for negative symptoms.1
Other pharmacologic agents,1 such as acetylcholine-related medications, oxytocin, and medications with a mechanism of action that is related to an inflammatory response and immunologic pathways (ie, minocycline), are being evaluated for treating negative symptoms. Research into the efficacy of glutamate-related agents also appears to be continuing.1
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