BackgroundBernstein’s heuristic model of personal strengths describes 16 positive attributes of the healthy adult self, grouped into four higher-order factors: self-directedness (identity, self-reflection, self-confidence, self-assertion, imagination/creativity), self-regulation (emotional balance, resilience, self-control, self-care, reality testing), connection (empathy, compassion, humour, responsibility), and transcendence (gratitude and wisdom). The study aimed to explore the factorial validity of Bernstein’s Strengths Scale developed for the assessment of these constructs. Furthermore, we explored the association of strengths with attention-deficit hyperactivity (ADHD) symptoms and mental health in a nonclinical sample using a network approach.MethodsFive hundred and twenty-eight adults filled out an online questionnaire, including Bernstein’s Strengths Scale (BSS), the Mental Health Continuum – Short Form (MHC-SF), and the Adult ADHD Self-Report Scale (ASRS).ResultsThough our data showed an acceptable fit to the 16-factor model, the Self-control subscale and item 28 of the Compassion subscale were excluded because of reliability issues. The final model with 15 factors and 44 items showed excellent fit, χ2(797) = 1130.149, p < .001, RMSEA = 0.028, 90% CI [0.024, 0.032], SRMS = 0.049, CFI = 0.993, TLI = 0.991. Principal component analysis revealed three instead of four second-order factors. In the network model, Self-confidence and Wisdom emerged as the most influential nodes. ADHD symptoms were negatively connected to Responsibility, Self-care, Identity, Emotional balance, Self-confidence, and mental health, while they had positive edges with Humor, Self-reflection, and Imagination/creativity. Mental health was positively related to several strengths, with the strongest association being between mental health and Gratitude.ConclusionThe BSS has acceptable factorial validity and is a reliable tool for assessing the personal strengths of the healthy adult self. ADHD symptoms in adults may be associated with deficits in personal strengths, but protective factors could also be identified. Addressing personal strengths in psychosocial interventions for ADHD in adults may improve patients’ emotional well-being and everyday functioning.