Which behavior was most significant in diagnosing a client with alcohol dependency?

The most significant behavior in diagnosing a client with alcohol dependency is the reports of increased alcohol use and memory loss. This option highlights two critical components typically associated with alcohol dependency: a pattern of escalating consumption and cognitive impairment.

Increased alcohol use is a direct indicator of problematic drinking behavior and is a key criterion in many diagnostic frameworks, such as the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders). This pattern of escalating use often points to the development of tolerance and potential physiological dependence, which are hallmarks of alcohol use disorder.

Memory loss, often referred to as blackouts or cognitive impairment in this context, indicates the detrimental effects of chronic alcohol consumption on the brain. Cognitive issues signal not only impaired functioning but also the potential for significant negative consequences stemming from alcohol use, further supporting a diagnosis of dependency.

While the other options may indicate problematic behaviors related to alcohol consumption, they do not directly encapsulate the core components of alcohol dependency as clearly as increased use and associated cognitive decline do. Legal problems and DUI convictions are serious but often reflect the consequences of alcohol use rather than the health implications or extent of dependency itself. Denial of prescription medication use, while potentially relevant, focuses on a separate issue and does not directly address alcohol dependency.