The Long-Term Outcomes of Prepubertal Depression and Internalizing Problems: A Scoping Review.

LEARNING OBJECTIVES: After participating in this activity, learners should be better able to:• Discuss whether prepubertal depression shows longitudinal continuity with depression in adulthood.• Summarize existing literature on adult emotional and functional outcomes of prepubertal depression and internalizing problems. BACKGROUND: Adolescent- and young adult-onset depression are common, recurrent, and can cause significant distress and psychosocial impairment across the life span, but recognition of prepubertal internalizing problems and depression, along with their prevalence, clinical course, and long-term outcomes, remains elusive. OBJECTIVE: To examine whether prepubertal depression, which can manifest differently from adult depression, shows longitudinal continuity with depression in adulthood, and to summarize existing literature on adult emotional and functional outcomes of prepubertal depression and internalizing problems. METHODS: A scoping review was conducted for peer-reviewed cohort articles published between 2000 and 2020 using PubMed and PsycINFO. From 4309 identified references, 17 articles were included. RESULTS: Prepubertal depression confers increased risk of recurrence of depression in adulthood, with similar findings for prepubertal internalizing problems. No studies found prepubertal depression or internalizing problems predicting adult substance abuse, and no studies asked about adult bipolar diagnoses. More research is needed to draw clear conclusions regarding their implications for other psychiatric, medical, or psychosocial outcomes. CONCLUSION: The reviewed studies provide limited evidence that prepubertal depression onset predicts adult depression. The small evidence base and heterogeneous methodological assessments may limit, however, the ability to draw meaningful conclusions about the long-term course of prepubertal-onset depression. Well-designed studies with longer follow-up and multiple assessments in adulthood are needed to clarify and assess the potential effects of prepubertal depression on adult health and functioning. This information will eventually become available as the samples in recently initiated longitudinal cohort studies of children mature further.

Methylphenidate-induced dendritic spine formation and DeltaFosB expression in nucleus accumbens.

Methylphenidate is the psychostimulant medication most commonly prescribed to treat attention deficit hyperactivity disorder (ADHD). Recent trends in the high usage of methylphenidate for both therapeutic and nontherapeutic purposes prompted us to investigate the long-term effects of exposure to the drug on neuronal adaptation. We compared the effects of chronic methylphenidate or cocaine (15 mg/kg, 14 days for both) exposure in mice on dendritic spine morphology and DeltaFosB expression in medium-sized spiny neurons (MSN) from ventral and dorsal striatum. Chronic methylphenidate increased the density of dendritic spines in MSN-D1 (MSN-expressing dopamine D1 receptors) from the core and shell of nucleus accumbens (NAcc) as well as MSN-D2 (MSN-expressing dopamine D2 receptors) from the shell of NAcc. In contrast, cocaine increased the density of spines in both populations of MSN from all regions of striatum. In general, the effect of methylphenidate on the increase of shorter spines (class 2) was less than that of cocaine. Interestingly, the methylphenidate-induced increase in the density of relatively longer spines (class 3) in the shell of NAcc was bigger than that induced by cocaine. Furthermore, methylphenidate exposure increased expression of DeltaFosB only in MSN-D1 from all areas of striatum, and surprisingly, the increase was greater than that induced by cocaine. Thus, our results show differential effects of methylphenidate and cocaine on neuronal adaptation in specific types of MSN in reward-related brain regions.