What is the most likely diagnosis for a medical student who has difficulty falling and staying asleep, with a history of anxiety and depression?

The most likely diagnosis in this scenario is insomnia, which is characterized by difficulty initiating or maintaining sleep. Given the history of anxiety and depression, it is particularly relevant as these conditions are commonly associated with sleep disturbances, including insomnia. Individuals with anxiety often find it hard to relax, leading to racing thoughts that can hinder their ability to fall asleep. Likewise, depression can result in sleep issues, whether it be insomnia or hypersomnia, but in this context, the problem is specified as difficulty falling and staying asleep.

Insomnia itself can manifest in various forms, and treatment typically involves addressing both the behavioral components and any underlying psychological issues, such as anxiety and depression. Recognizing insomnia in the context of comorbid mental health conditions is crucial for proper management.

Other choices, such as behaviorally induced insufficient sleep syndrome, obstructive sleep apnea, and merely attributing the symptoms to anxiety and depression alone, do not fully encapsulate the specific sleep problems presented. For instance, while obstructive sleep apnea might also cause sleep disruption, it is characterized more by physical symptoms such as snoring and choking during sleep, which are not mentioned here. Therefore, insomnia is the most fitting diagnosis in this situation.