How many specialists and residents in Clinical Psychology are required in the Spanish National Health System? A needs-based study

Abstract Background The Spanish National Health System (NHS) faces a significant shortage of clinical psychologists with only 5.58 per 100,000 inhabitants. This study aimed to estimate the required number of specialists and residents in Clinical Psychology to provide adequate psychological treatments to the population in the NHS. Methods A needs-based model was adapted to forecast the required total number of clinical psychologists and the annual increase in the positions of residents in Clinical Psychology (PIR). This model followed five steps: (1) obtaining Spanish prevalence rates for three broad mental disorder categories (depression, anxiety, and others or severe mental disorders) from the 2017 National Health Survey (ENSE); (2) multiplying the prevalence rates by the Spanish population aged ≥ 15 years; (3) defining the percentage of cases eligible for treatment under three predefined scenarios (protocolized, intermediate, and adjusted); (4) operationalizing the characteristics of the three treatment scenarios (session number and duration); and (5) calculating the total number of clinical psychologists and the annual increase required for PIR positions. Results Depending on the treatment scenario, the estimations show a need for clinical psychologists ranging from 1665 to 13,527 for treating depressive disorders, 1792–9799 for anxiety disorders, and 2074–8294 specifically for severe mental disorders. On the other hand, depending on the treatment scenario and the timeframe to achieve the estimated number of professionals (within 3, 5, 8, or 10 years), for example, to achieve those estimations of professionals within 3 years, and according to the adjusted treatment scenario, the Spanish health system should offer approximately 481 PIR positions yearly during 3 years. Conclusions A significant increase in the number of PIR positions is necessary to meet the growing demand for psychological treatment in the Spanish NHS. Investing in a mental-health workforce can lead to substantial health and economic benefits. This study provides valuable insights for workforce planning and highlights the importance of addressing the shortage of clinical psychologists in the NHS.