Discussion
This transdiagnostic study found reduced grip strength in schizophrenia, current depression , and remitted depression compared with healthy controls. Depression groups showed lower grip strength than schizophrenia, but with no difference between them.
These findings suggest that reduced grip strength reflects transdiagnostic mechanisms involving motor control, sensory integration, and motivation.3,4 In depression, persistent reductions during remission may reflect residual symptoms, such as psychomotor or executive dysfunction, indicating that remission does not fully normalize psychomotor performance.5 In schizophrenia, associations with negative symptoms, particularly in avolition, affect, and alogia domains, might highlight the role of disrupted frontal–striatal circuits and dopaminergic dysfunction in translating motivational drive into motor output.
The sex-specific pattern, with associations primarily in males, underscores the need to consider sex differences in both symptom expression and motor performance when interpreting biomarker data.6
Limitations include not adjusting for body mass index, occupation, physical activity, hormonal status, and medication use, the cross-sectional study design, and pooling data from 2 study sites.
Nevertheless, the results highlight low grip strength as a potential transdiagnostic biomarker, reflecting motor and motivational dysfunction, persisting into remission, and showing diagnosis and sex-specific symptom associations.
This underscores the value of grip strength for early detection and intervention that should be examined in other psychiatric disorders beyond schizophrenia and depression.
