This systematic review and meta-analysis evaluates the efficacy of nonpharmacological therapies (NPTs) in Alzheimer's disease (AD) and related disorders (ADRD). The study included 179 randomized controlled trials (RCTs) across 26 intervention categories, focusing on cognitive deterioration and degenerative etiology. Key findings include: 1. **Institutionalization Delay**: Multicomponent interventions for caregivers (CGs) significantly delayed institutionalization rates for AD patients. 2. **Cognition Improvement**: Cognitive training and stimulation improved specific cognitive skills, with positive effects observed in verbal and visual learning, attention, memory, orientation, language, and general cognition. 3. **Activities of Daily Living (ADLs)**: ADL training improved performance in urinary incontinence, eating independence, and way-finding. 4. **Behavioral Improvements**: Cognitive stimulation and behavioral interventions reduced problem behaviors and agitation in AD patients. 5. **Mood Enhancement**: Multicomponent interventions for AD patients improved affective symptoms, particularly depression and anxiety. 6. **CG Quality of Life (QoL)**: Multicomponent interventions for AD patients and CGs improved CG QoL through home environment adaptation and continuous counseling. 7. **CG Psychological Well-being (PWB)**: Cognitive stimulation improved CG PWB, particularly in those with high levels of depression or anxiety. 8. **CG QoL**: Comprehensive interventions for AD patients and CGs improved CG QoL through in-home counseling and support groups. The review highlights the potential of NPTs as a cost-effective and versatile approach to improve outcomes and QoL in ADRD, complementing pharmacological treatments. However, methodological issues such as small sample sizes, lack of theoretical models, and inadequate outcome measures were noted. Future research should focus on high-quality RCTs, particularly in areas with theoretical frameworks and low intervention costs.This systematic review and meta-analysis evaluates the efficacy of nonpharmacological therapies (NPTs) in Alzheimer's disease (AD) and related disorders (ADRD). The study included 179 randomized controlled trials (RCTs) across 26 intervention categories, focusing on cognitive deterioration and degenerative etiology. Key findings include: 1. **Institutionalization Delay**: Multicomponent interventions for caregivers (CGs) significantly delayed institutionalization rates for AD patients. 2. **Cognition Improvement**: Cognitive training and stimulation improved specific cognitive skills, with positive effects observed in verbal and visual learning, attention, memory, orientation, language, and general cognition. 3. **Activities of Daily Living (ADLs)**: ADL training improved performance in urinary incontinence, eating independence, and way-finding. 4. **Behavioral Improvements**: Cognitive stimulation and behavioral interventions reduced problem behaviors and agitation in AD patients. 5. **Mood Enhancement**: Multicomponent interventions for AD patients improved affective symptoms, particularly depression and anxiety. 6. **CG Quality of Life (QoL)**: Multicomponent interventions for AD patients and CGs improved CG QoL through home environment adaptation and continuous counseling. 7. **CG Psychological Well-being (PWB)**: Cognitive stimulation improved CG PWB, particularly in those with high levels of depression or anxiety. 8. **CG QoL**: Comprehensive interventions for AD patients and CGs improved CG QoL through in-home counseling and support groups. The review highlights the potential of NPTs as a cost-effective and versatile approach to improve outcomes and QoL in ADRD, complementing pharmacological treatments. However, methodological issues such as small sample sizes, lack of theoretical models, and inadequate outcome measures were noted. Future research should focus on high-quality RCTs, particularly in areas with theoretical frameworks and low intervention costs.