<p>Depression is a severe mental health disorder that profoundly affects individuals, characterized by persistent sadness, reduced enthusiasm, and impaired concentration, ultimately impacting daily life. Early and precise diagnosis is essential yet challenging, as traditional approaches rely heavily on subjective evaluations by mental health professionals, often resulting in delayed intervention. Recent advancements have explored the use of machine learning techniques to automatically estimate depression severity through speech analysis. Although prior methods have demonstrated effectiveness, there remains potential for further performance improvement. This paper introduces a novel deep spectrotemporal network designed to estimate depression severity scores from vocal cues. Specifically, we propose extracting holistic and localized spectral features using the pre-trained EfficientNet-B3 model from Mel spectrogram sequences and capturing spatiotemporal dynamics through our novel Volume Local Neighborhood Encoded Pattern (VLNEP) descriptor. Finally, a dual-stream transformer model is designed to effectively fuse and learn these extracted spectral and spatiotemporal features. Experimental results on the benchmark AVEC2013 and AVEC2014 datasets demonstrate the superiority of our proposed framework compared to state-of-the-art methods.</p>