Mental health conditions are a significant contributor to the global burden of disease. The aim of this study was to explore the association between psychological disorders, Mediterranean diet (MD), and chronotype. A total of 344 participants (74% women) with a mean age of 33.5 ± 13 years were recruited. According to the Depression Anxiety Stress Scale (DASS-21) score, 22% of participants had symptoms of depression, 23% anxiety, and 10% stress. The assessment of MD adherence through the Medi-Lite score revealed that participants with psychological disorders had significantly (p < 0.05) lower MD adherence than those without these conditions. Furthermore, less than 10% of the subjects with at least one symptom reported consuming the optimal amount of fruit and vegetables, while 72% showed excessive consumption of meat and meat products. Regarding chronotype, evening subjects reported the lowest MD adherence and the highest prevalence of all three psychological disorders analyzed. A multivariate analysis showed that female gender, age, being unmarried/single, sedentary lifestyle, and low MD adherence were associated with a significantly higher risk of depression, anxiety, and stress. Future studies are needed to explore the relationship between mental health and risk factors to improve personal and global population health.