Differential Diagnosis for Depression, Fatigue, and Substance Use
Single Most Likely Diagnosis
- Major Depressive Disorder (MDD): Given the combination of depression, fatigue, and substance use, MDD is a highly plausible diagnosis. Substance use can be both a contributing factor to and a result of depression, and fatigue is a common symptom of MDD.
Other Likely Diagnoses
- Substance Use Disorder: The presence of substance use alongside depression and fatigue suggests that a substance use disorder could be a primary or contributing diagnosis. Substance use can lead to or exacerbate feelings of depression and fatigue.
- Bipolar Disorder: Fatigue and depression can be part of the depressive phase of bipolar disorder, and substance use is common among individuals with bipolar disorder as a form of self-medication.
- Anxiety Disorders: Anxiety can manifest with symptoms of depression and fatigue, and substance use may be an attempt to self-medicate anxiety symptoms.
- Post-Traumatic Stress Disorder (PTSD): PTSD can lead to symptoms of depression, fatigue, and substance use as a coping mechanism for trauma.
Do Not Miss Diagnoses
- Hypothyroidism: Although less likely, hypothyroidism can cause depression, fatigue, and potentially contribute to substance use as a way to cope with symptoms. Missing this diagnosis could lead to prolonged suffering and potential worsening of symptoms.
- Sleep Apnea: Sleep disorders like sleep apnea can cause significant fatigue and contribute to depression and substance use. Untreated sleep apnea can have serious health consequences.
- Chronic Fatigue Syndrome (Myalgic Encephalomyelitis): This condition is characterized by profound fatigue that is not improved by rest and can be accompanied by depression and potentially substance use as a coping mechanism.
Rare Diagnoses
- Wilson's Disease: A rare genetic disorder that can lead to psychiatric symptoms including depression, and fatigue, among other systemic symptoms. It's crucial to consider in younger patients with unexplained psychiatric and neurological symptoms.
- Mitochondrial Disorders: These are a group of rare genetic disorders that can affect various parts of the body, including the brain, and may present with symptoms of depression, fatigue, and potentially substance use as a way to cope with chronic illness.
- Chronic Infectious Diseases (e.g., Lyme Disease, HIV): Certain chronic infections can present with a wide range of symptoms including depression, fatigue, and substance use, either as a direct effect of the infection or as a result of the chronic stress and disability associated with the illness.