This book chapter explores the development of an expert system for diagnosing mental health disorders, aimed at assisting psychology professionals in identifying a variety of psychological conditions. The system evaluates both physical and emotional symptoms to provide accurate diagnoses of disorders such as anxiety, adjustment, impulse control, mood, and neurocognitive disorders, which can cause significant micro-level impacts on individuals. The chapter introduces an innovative approach using three artificial intelligence techniques: fuzzy generator, fuzzy logic, and rule-based reasoning. A key feature is the design of a weighted fuzzy rule system, where the IF part directly influences the THEN outcome in a causal manner. Human expert knowledge in the field of mental health is encoded into the system’s knowledge base using fuzzy logic, allowing the system to assess the severity of different disorders. The objective of this chapter is to provide an in-depth understanding of how AI-based expert systems can be applied to the diagnosis and management of psychological disorders, offering a new method for enhancing clinical decision-making in mental health.