証拠の質 4.88/5
8次元のレビュー評価。基準は 品質ルーブリック 。各次元は1〜5で評価。
- D1 出典への根拠
- 5/5
- D2 出典の権威性
- 5/5
- D3 算術
- 5/5
- D4 不確実性
- 5/5
- D5 範囲
- 5/5
- D6 文章
- 5/5
- D7 認識の誠実性
- 4/5
- D8 注意事項の完全性
- 5/5
リスクはどう変わるか
見出しの数値は大きく異なる状況の平均です。シナリオや文脈による確率の違いは以下の通りです:
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No reliable per-user probability can be assigned. Correlational studies find small negative associations with well-being (r ≈ 0.035-0.15), but these are measured on continuous scales, not as binary harm incidence. For the typical teen user at moderate usage levels, the population-level effect size is too small and too heterogeneous to convert into a meaningful individual risk number.
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Heavy use is associated with larger negative effects in most studies, but the dose-response curve is inconsistent across datasets and may reflect reverse causation (teens who are already struggling use social media more). No study has produced a reliable incidence rate for clinical-level harm among heavy users specifically.
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The largest documented subgroup effects in the literature. Facebook/Instagram internal research (2021) and several external studies find that girls with pre-existing internalising symptoms report the most negative experiences. Effect sizes are larger than the population average but still measured on well-being scales rather than as binary harm rates. This is the subgroup where the case for a clinically meaningful effect is strongest and where a per-user probability would be most useful — but the evidence does not yet support one.
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Most studies find smaller or null associations between social media use and well-being outcomes in boys compared to girls. Some studies find positive associations with social connection. The gender difference is one of the more consistent findings in the literature, though it may partly reflect differences in platform use patterns (visual comparison-based content vs. gaming/interest-based content) rather than a biological sex difference.
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A distinct and newer exposure from feed-based social media. Common Sense Media (2025) found 72% of US teens have used an AI companion and about half use them regularly, but adoption rate is not a harm rate. The hypothesised mechanism — a private, always-available, sycophantic chat that can isolate a teen and fail to interrupt an escalating crisis — is drawn from individual cases (the Sewell Setzer III suicide and Garcia v. Character.AI; the OpenAI/Adam Raine case) and litigation now settling (the Google/Character.AI settlement in principle, January 2026), not from any cohort study with an incidence rate. No reliable per-user probability exists for crisis or self-harm outcomes tied to companion-bot use; the evidence base is adoption surveys and case reports, not population data.
バーの長さと濃淡は、これらのシナリオを他のリスクとではなく、互いに比較して順位付けしたものです。正確な確率は各項目の横に表示されています。
このリスクが関わる決断
このリスク次第で変わる選択。そのトレードオフをどう見るか。
比較対象を選択
この項目には「信頼できる推定値なし」のフラグが付いており、その理由は明確にする価値があります。ソーシャルメディアとティーンの精神衛生に関する研究文献は、数千もの研究、複数の政府勧告、そして少なくとも1冊のベストセラー本を生み出してきましたが、「深刻な心理的危害」のユーザーごとの防御可能な確率を生み出すには至っていません。最も強力な相関分析、すなわちOrbenとPrzybylskiによる350,000人以上の青少年を対象とした2019年の仕様曲線研究、およびOdgersとJensenによって統合された2023年以降のレビューでは、r = 0.035からr = 0.15の範囲の関連性が見られます。これらの数値はゼロではありません。しかし、「X人のティーンのうち1人が深刻な危害を受ける」といった意味のある記述に変換できるほど大きくもありません。成果指標は連続的な幸福度尺度であり、二値的な危害の閾値ではありません。「生活満足度調査でわずかに低いスコアを記録した」と「Instagramが原因で臨床的な不安障害を発症した」との間の隔たりは、データでは埋めることができません。
ここでの認識のギャップは、通常とは異なる方向に生じています。米国公衆衛生局長官の2023年勧告(このトピックに関する最も権威ある単一文書)は、「ソーシャルメディアが子供や青少年に十分安全であると判断するのに十分な証拠はまだない」と明示的に述べています。この表現は、Facebook/Instagramの内部研究漏洩やHaidtのThe Anxious Generationと相まって、ソーシャルメディアがほとんどのティーンエイジャーにとって明白かつ差し迫った危険であると見なす方向へ世間の直感を動かしました。相関関係の文献は、より弱い主張を支持しています。それは、実在するものの小さな集団レベルの関連性であり、より大きな影響は特定のサブグループ(13~15歳の女子、既存の内向的症状を持つティーン、1日3~4時間以上のヘビーユーザー)に集中しているというものです。これらのサブグループ効果が因果的な精神衛生上の危機を構成するのか、それとも逆因果関係や交絡を反映しているのかが中心的な未解決問題であり、2026年時点での正直な答えは、この分野ではまだ解決されていないということです。
この数値が最も重要となるであろう場所、つまりすでに不安を抱え、1日4時間Instagramを利用している14歳の少女の親にとっては、まさに証拠が最も示唆的でありながら最も不正確な場所です。Facebookの内部研究では、すでに自分の体について気分が悪かったティーンの女子の32%がInstagramによってそれが悪化したと回答しましたが、内部調査における「気分が悪くなった」は「診断可能な状態を発症した」とは異なり、その調査は母集団を代表するものではありませんでした。この分野が臨床的成果の定義に合意し、大規模な代表コホートでそれを前向きに測定するまで、この項目は信頼できる推定値がないものとしてフラグが立てられたままになります。それはソーシャルメディアが安全であるという声明ではありません。それは、現状の証拠が特定の数値を支持していないという声明です。
関連する豆知識
根拠台帳
以下の各数値は各出典が報告した内容であり、引用した原文の抜粋と算出方法を記載しています。リンクをクリックして直接確認できます。
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[1] Office of the U.S. Surgeon General (2023) — Social Media and Youth Mental Health: The U.S. Surgeon General's Advisory
Social Media and Youth Mental Health: The U.S. Surgeon General's Advisory- 統計値
The advisory states there is 'not enough evidence to determine that social media is sufficiently safe for children and adolescents' and calls for urgent action, while noting the evidence base is insufficient to establish causation or quantify per-user risk- 抜粋
“"We do not yet have enough evidence to determine that social media is sufficiently safe for children and adolescents." ”
- 出典データ
- 2023-05-23
- アクセス日
- 2026-04-18 · アーカイブ版
- 計算過程
- The Surgeon General's Advisory is the highest-profile US government statement on teen social media risk. It is cited here as an authoritative framing document, not as a source of a specific probability. The advisory explicitly avoids stating a per-user risk figure and notes the evidence base is insufficient to determine whether social media is safe. It summarises the correlational literature and calls for more research, platform transparency, and legislative action. No native or normalized probability is derived from this source because the entry is flagged no_reliable_estimate.
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[2] Nature Human Behaviour (Orben & Przybylski 2019) — The association between adolescent well-being and digital technology use
The association between adolescent well-being and digital technology useSee all 2 Likelier entries citing this source →
- 統計値
Across three large-scale datasets (total N > 350,000), the association between digital technology use and adolescent well-being was negative but small: r = −0.035 for social media use specifically, explaining about 0.4% of the variance in well-being — less than the negative association with wearing glasses or eating potatoes- 抜粋
“"The negative effect of technology use on adolescent well-being is small — explaining at most 0.4% of the variation in well-being." ”
- 出典データ
- 2019-01-14
- アクセス日
- 2026-04-18 · アーカイブ版
- 計算過程
- Orben & Przybylski 2019 is the most-cited methodological counterweight to the crisis narrative. The specification-curve analysis across all defensible analytic choices produces effect sizes that are statistically significant (large N) but tiny in practical terms. r = −0.035 for social media use means the association explains roughly 0.12% of the variance in well-being. This is not zero, but it is far too small to convert into a per-user probability of "serious psychological harm" — the outcome variable is a continuous well-being scale, not a binary harm threshold. This source is the primary basis for the no_reliable_estimate designation: the effect is real but not meaningfully translatable into individual risk.
- 独立性
- Fully independent of the Surgeon General's Advisory and the Facebook internal research. Uses UK Understanding Society, YRBS, and MCS datasets.
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[3] American Psychological Association (2023) — Health Advisory on Social Media Use in Adolescence
Health Advisory on Social Media Use in AdolescenceSee all 2 Likelier entries citing this source →
- 統計値
The APA identifies social media as neither uniformly beneficial nor uniformly harmful, and notes that effects depend on the content, the adolescent's individual characteristics, and the amount of time spent; it provides no per-user probability of harm- 抜粋
“"Science demonstrates that social media use, in and of itself, is not sufficient to be helpful or harmful to young people." ”
- 出典データ
- 2023-05-09
- アクセス日
- 2026-04-18 · アーカイブ版
- 計算過程
- The APA health advisory is included as a second authoritative institutional statement. Like the Surgeon General's Advisory, it summarises the correlational literature without producing a probability figure. Its key contribution to this entry is the explicit statement that social media use "in and of itself" is insufficient to cause harm — effects depend on content type, individual vulnerability, and usage patterns. This supports the no_reliable_estimate framing: there is no single population-level probability that applies to "a teenager using social media."
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[4] Wall Street Journal (Wells, Horwitz, Seetharaman 2021) — Facebook Knows Instagram Is Toxic for Teen Girls, Company Documents Show
Facebook Knows Instagram Is Toxic for Teen Girls, Company Documents Show- 統計値
Internal Facebook research found that 32% of teen girls surveyed said Instagram made them feel worse about their body when they already felt bad about it; the research also found Instagram was cited as a contributor to anxiety and depression in a subset of teen users- 抜粋
“"Thirty-two percent of teen girls said that when they felt bad about their bodies, Instagram made them feel worse." ”
- 出典データ
- 2021-09-14
- アクセス日
- 2026-04-18 · アーカイブ版
- 計算過程
- The WSJ Facebook Files series leaked internal Instagram research that became the public catalyst for legislative and regulatory action. The "32% of teen girls" figure is widely cited but refers to a specific question — "when you already feel bad about your body, does Instagram make it worse?" — not to a base rate of developing a clinical condition. The leaked research used convenience-sampled internal surveys, not population-representative methods, and "felt worse" is a subjective self-report, not a clinical diagnosis of serious psychological harm. Included because it drove the public perception shift, not because it anchors a probability.
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[5] Journal of Child Psychology and Psychiatry (Odgers & Jensen 2020) — Annual Research Review: Adolescent mental health in the digital age: facts, fears, and future directions
Annual Research Review: Adolescent mental health in the digital age: facts, fears, and future directions- 統計値
Synthesising six prior reviews/meta-analyses plus large-scale preregistered cohort and momentary-assessment studies, the review finds the link between digital technology use and adolescent mental health to be a mix of conflicting small positive, negative, and null associations (e.g. Huang 2017 meta-analysis r = −0.07 overall, depression r ≈ −0.11; McCrae 2017 r = 0.13), with no support for causal claims at the population level- 抜粋
“"At present, narrative reviews and meta-analytic work do not support causal claims, or even strong and consistent correlational patterns, linking adolescents' digital technology usage with mental health problems." ”
- 出典データ
- 2020-01-17
- アクセス日
- 2026-04-18 · アーカイブ版
- 計算過程
- Odgers & Jensen 2020 (J Child Psychol Psychiatry Annual Research Review) synthesises three evidence streams: narrative reviews and meta-analyses (2014-2019), large-scale preregistered cohort studies, and intensive longitudinal / ecological-momentary-assessment studies. Across them the reported associations are small and inconsistent in direction — the Huang (2017) meta-analysis (N = 19,652) found a mean SNS-well-being correlation of r = −0.07 (depression r ≈ −0.11), and the McCrae (2017) meta-analysis found r = 0.13 for depressive symptoms. The review's key contribution to this entry is its conclusion that the evidence base does not support causal claims, "or even strong and consistent correlational patterns," and does not warrant the widespread panic — while the outcome measures remain continuous well-being and symptom scales, not binary harm thresholds. (Earlier drafts of this entry mis-cited this review under a Clinical Psychological Science DOI that in fact resolves to Vuorre & Przybylski 2023, "Global Well-Being and Mental Health in the Internet Age" — a separate paper; the identifier was corrected to the real Odgers & Jensen 2020 DOI 10.1111/jcpp.13190 in 2026.)
- 独立性
- Independent review drawing on a broader evidence base than Orben & Przybylski 2019, including six prior systematic reviews/meta-analyses, large-scale preregistered cohort studies (e.g. Understanding Society, N = 12,672), and diary/EMA designs.
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[6] Common Sense Media (2025) — Talk, Trust, and Trade-Offs: How and Why Teens Use AI Companions
Talk, Trust, and Trade-Offs: How and Why Teens Use AI Companions- 統計値
In a nationally representative survey of 1,060 US teens aged 13-17 (April-May 2025), nearly three in four teens (72%) had used an AI companion at least once and roughly half were regular users; the figure is an adoption rate, not a rate of resulting psychological harm- 抜粋
“"Our new research reveals that nearly three in four teens have used AI companions, and half use them regularly." ”
- 出典データ
- 2025-07-16
- アクセス日
- 2026-06-14 · アーカイブ版
- 計算過程
- Added 2026-06-14 to document AI companion chatbots as a distinct emerging teen-harm vector separate from feed-based social media. Common Sense Media's nationally representative survey establishes that the exposure is now mainstream (72% of teens have tried one; ~half are regular users). It is cited strictly as an adoption-prevalence figure: the survey measures how many teens use companion bots, not how many are harmed by them. No native or normalized probability is derived because the entry remains no_reliable_estimate — surveys report adoption, not crisis incidence.
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[7] UNICEF (2026) — 'Deepfake abuse is abuse' — Statement by UNICEF on AI-generated sexualised images of children
'Deepfake abuse is abuse' — Statement by UNICEF on AI-generated sexualised images of children- 統計値
In a UNICEF, ECPAT and INTERPOL study across 11 countries (Disrupting Harm Phase 2, ~1,000 internet-using children aged 12-17 surveyed per country), at least 1.2 million children disclosed having had their images manipulated into sexually explicit deepfakes in the past year; in some countries this represents 1 in 25 children- 抜粋
“"In a UNICEF, ECPAT and INTERPOL study across 11 countries, at least 1.2 million children disclosed having had their images manipulated into sexually explicit deepfakes in the past year. In some countries, this represents 1 in 25 children — the equivalent of one child in a typical classroom." ”
- 出典データ
- 2026-02-04
- アクセス日
- 2026-06-14 · アーカイブ版
- 計算過程
- Added 2026-06-14 to ground the AI-synthetic-media caveat. The original change brief attributed this 1.2-million figure to Thorn; that attribution could not be verified. The figure is actually from the UNICEF/ECPAT/INTERPOL Disrupting Harm Phase 2 study, cited here from the verbatim UNICEF statement. It is a cross-national exposure-disclosure rate (children reporting their images were manipulated into sexual deepfakes), not a per-user probability of psychological harm, so it does not change the no_reliable_estimate status. It documents that generative-AI synthetic media is a victimisation channel distinct from, and sometimes embedded within, social-media platforms.

