Cortical Thickness of the Salience Network and Change in Apathy Following Antidepressant Treatment for Late-Life Depression.

OBJECTIVE: Apathy is common in late-life depression and is associated with poor response to antidepressant drugs. In depressed older adults, apathy may be characterized by neuroanatomical abnormalities of the salience network. The current study examined whether cortical thickness of select salience network structures predicted change in apathy following a 12-week treatment with escitalopram. METHODS: A sample of 46 older adults with major depressive disorder received 12 weeks of escitalopram treatment at a daily target dose of 20 mg. All participants underwent a structural brain MRI scan at baseline, and cortical thickness was estimated in key cortical nodes of the salience network: the caudal anterior cingulate cortex and the insula. We measured baseline and post-treatment symptoms using the Apathy Evaluation Scale and the Hamilton Depression Rating Scale. RESULTS: A thicker insula at baseline predicted reduction in apathy symptoms following 12 weeks of treatment with escitalopram, even when controlling for age, baseline depression severity and change in depressive symptoms. CONCLUSION: Reduced insular thickness predicted residual apathetic symptoms following escitalopram treatment. These results converge with our previous findings of abnormal functional connectivity of the insular cortex in older depressed individuals with apathy. Older depressed adults with apathy may benefit from alternative treatment approaches or augmentative interventions that target abnormalities of the salience network.

Cannabis use and psychiatric illness in the context of medical marijuana legalization: A clinical perspective.

OBJECTIVE: More than half of the U.S. states have legalized medical marijuana. Emerging evidence suggests that medical marijuana legalization may increase marijuana use and cannabis use disorder (CUD). CUD is comorbid with, and exacerbates, numerous psychiatric conditions, including misuse of other substances. It is unclear if marijuana is a gateway to other drug use, if it is simply a marker of another variable or shared experiences. Thus, we aim to present a perspective of the potential impact of medical marijuana legalization on CUD, focusing on the relationship of CUD to other psychiatric disorders. FINDINGS: Medical marijuana legalization may lead to problematic cannabis use in patients with depressive symptoms, individuals with genetic predispositions, and those with certain early life stressors or who use in order to cope. Past positive experience with marijuana use may contribute to patient desire to seek medical marijuana treatment. Despite approved indications, medical marijuana often only leads to partial relief of its intended target symptom. While recreational marijuana use increases likelihood of using other drugs and is detrimental to recovery from other substance use disorders, the relationship between medical marijuana use and polysubstance use or risk of addiction relapse is uncertain. CONCLUSIONS AND RELEVANCE: Legalized medical marijuana use may increase rates of CUD, although further research is needed to clarify this association. Based on the literature, it is our perspective that patients with affective symptoms and those with other substance use disorders are at increased risk of developing CUD and its sequelae. Given the uncertainty surrounding how prescribed marijuana may interact with other disorders, it is paramount that clinicians make patient-specific judgments as to the risks and benefits of the treatment.

Executive functioning complaints and escitalopram treatment response in late-life depression.

OBJECTIVE: Executive dysfunction may play a key role in the pathophysiology of late-life depression. Executive dysfunction can be assessed with cognitive tests and subjective report of difficulties with executive skills. The present study investigated the association between subjective report of executive functioning complaints and time to escitalopram treatment response in older adults with major depressive disorder (MDD). METHODS: 100 older adults with MDD (58 with executive functioning complaints and 42 without executive functioning complaints) completed a 12-week trial of escitalopram. Treatment response over 12 weeks, as measured by repeated Hamilton Depression Rating Scale scores, was compared for adults with and without executive complaints using mixed-effects modeling. RESULTS: Mixed effects analysis revealed a significant group × time interaction, F(1, 523.34) = 6.00, p = 0.01. Depressed older adults who reported executive functioning complaints at baseline demonstrated a slower response to escitalopram treatment than those without executive functioning complaints. CONCLUSION: Self-report of executive functioning difficulties may be a useful prognostic indicator for subsequent speed of response to antidepressant medication.